bio 180 final

HIV, the causative agent of AIDS, is a retrovirus. A retrovirus ________.

uses reverse transcriptase to make DNA from RNA

Beadle and Tatum discovered that metabolic pathways are studied most effectively using which of the following techniques?

using single gene mutations resulting in nonfunctional enzymes specific to a metabolic pathway

Brown et al. and Morwood et al. reported in 2004 that they had found skeletal remains of a previously unknown type of hominin, now dubbed Homo floresiensis, on the Indonesian island of Flores. These hominins were small (approximately 1 meter tall) with small braincases (approximately 380 cubic centimeters) as compared with other hominins. The remains of H. floresiensis were found alongside handmade stone tools and the remains of dwarf elephants that also inhabited the island, suggesting that H. floresiensis was able both to make tools and to coordinate the hunting of animals much larger than itself. H. floresiensis is estimated to have lived at the site where the remains were found from at least 38,000 years ago to 18,000 years ago. Referring to the paragraph above, think about the most feasible method to evaluate which other hominin species H. floresiensis was most closely related. You could compare ________

skeletal morphology of H. floresiensis to that of each of the other hominin species

Which of the following is an example of polygenic inheritance?

skin pigmentation in humans

What would be the most direct effect of removing or damaging an insect's antennae? The insect would have trouble ________.

smelling

In the accompanying figure, which species is the stronger competitor?

species 1

A botanist discovers a new species of land plant with a dominant sporophyte, chlorophylls a and b, and cell walls made of cellulose. In assigning this plant to a phylum, which of the following, if present, would be LEAST useful?

spores

Which of these are spore-producing structures?

sporophyte (capsule) of a moss

In the process of alternation of generations, the ________.

sporophyte is diploid and produces spores

Which of the following could use reverse transcriptase to transcribe its genome?

ssRNA

Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation?

stabilizing selection

Use the following information to answer the question(s) below. Martin Wikelski and L. Michael Romero (Body size, performance, and fitness in Galápagos marine iguanas, Integrative and Comparative Biology 43 [2003]: 376—86) measured the snoutto-vent (anus) length of Galápagos marine iguanas and observed the percent survival of different-sized animals, all of the same age. The graph shows the log snout—vent length (SVL, a measure of overall body size) plotted against the percent survival of these different-size classes for males and females. Examine the accompanying figure. What type of selection for body size appears to be occurring in these marine iguanas?

stabilizing selection

Proto-oncogenes ________.

stimulate normal cell growth and division

A population of viruses with similar characteristics is called a ________.

strain

The same basic internal organs (kidneys, stomach, heart, lungs) are found in frogs, birds, snakes, and rodents. This is primarily an example of ________.

structural homology

Proteomics is defined as the ________.

study of the full protein set encoded by a genome

Imagine that you are given some chemoorganotrophic bacteria to grow. What should you use as a source of energy for this type of bacteria?

sugar

The main reason polar regions are cooler than the equator is that ________.

sunlight strikes the poles at a lower angle

Comb jellies may not be the most familiar animal to you, but they are critical in the food chain because they make up a significant portion of the planktonic biomass. Their feeding strategy is predatory and involves adhesives or mucus on their tentacles or other body parts. What feeding tactic do these animals use?

suspension feeder

Which of the following is most likely to be aquatic?

suspension feeder

Sponges are most accurately described as ________.

suspension feeders

From the information provided in the accompanying table, how would you classify the feeding strategy of organism C?

suspension feeding and predation

The origin of a new plant species by hybridizing two existing species, coupled with accidents during cell division, is an example of ________.

sympatric speciation and allopolyploidy

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood. The host mammal can be considered as the fleas' habitat. If this situation persists, and new species evolve, this would be an example of ________.

sympatric speciation and habitat isolation

Among known plant species, which of these have been the two most commonly occurring phenomena that have led to the origin of new species?

sympatric speciation and polyploidy

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers but mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it?

sympatric speciation; habitat isolation

A small number of birds arrive on an island from a neighboring larger island. This small population begins to adapt to the new food plants available on the island as selection favors those birds with larger beaks. About twice a year, one or two more birds from the neighboring island arrive. These new arrivals ________.

tend to retard adaptation to the new food plants

Twenty-five years ago, when Oshima and colleagues discovered that a mutation in the GAL4 gene led to the inability to synthesize all five enzymes required for galactose catabolism (breakdown), they couldn't be blamed for wanting to apply a bacterial model to explain this finding. What they expected, but did not find, was ________.

that all five genes constitute an operon

In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and ________ of the last nucleotide in the polymer.

the 3' OH

An example of a basal transcription factor is ________.

the TATA-binding protein

Biological fitness is best defined as

the ability of an individual to produce offspring that survive and reproduce, relative to other individuals in the population.

Given the damage caused by UV radiation, the kind of gene affected in those with XP is one whose product is involved with ________.

the ability to excise single-strand damage and replace it

Which adaptation is unique to insects among all protostomes?

the ability to move by flying

Death cap mushrooms produce a substance called alpha-amanitin. Alpha-amanitin efficiently blocks synthesis of mRNA, but not of tRNA or rRNA, in eukaryotic organisms. This is possible because alpha-amanitin efficiently interferes with ________.

the action of RNA polymerase II, but not RNA polymerase I or III

Which structure of the amniotic egg most closely surrounds the embryo?

the amnion

Which evolutionary innovation was most significant in helping tetrapods move to dry terrestrial environments?

the amniotic egg

The product of the bicoid gene in Drosophila provides essential information about ________.

the anterior—posterior axis

What ensures that the correct amino acid is added during translation?

the anticodon of a properly formed aminoacyl tRNA

The definition of a generation is ________.

the average time between a mother's first offspring and her daughter's first offspring

Turnover of water in temperate lakes during the spring and fall is made possible by which of the following?

the changes in the density of water as seasonal temperatures change

What provides the energy for the polymerization reactions in DNA synthesis?

the deoxyribonucleotide triphosphate substrates

Which of the following is an exception to the central dogma?

the discovery of RNA viruses that synthesize DNA using reverse transcriptase

Two competing hypotheses to account for the increase in the number of Hox genes from the last common ancestor of bilaterians to the last common ancestor of insects and vertebrates are: (1) a single duplication of the entire four-gene cluster, followed by the loss of one gene, and (2) three independent duplications of individual Hox genes. To prefer the first hypothesis on the basis of parsimony requires the assumption that ________.

the duplication of a cluster of four Hox genes is equally likely to the duplication of a single Hox gene

What is a telomere?

the ends of linear chromosomes

Gastrulation is an important event in early embryonic development. Which of the following is NOT a result of gastrulation?

the formation of specialized adult tissues

In the accompanying figure, which individuals are displaying Batesian mimicry?

the hornet moth, wasp beetle, and hoverfly

If alternative splicing did NOT occur, then ________.

the human genome would likely contain many more genes

Global warming refers to ________.

the increase in the average temperature of the whole planet

According to the figure shown, a species has the highest chance of extinction when ________.

the island is small and remote

The leading and the lagging strands differ in that ________.

the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction

The term "homoplasy" is most applicable to which of the following features?

the legless condition found in various lineages of extant lizards

The virus genome and viral proteins are assembled into virions (virus particles) during ________.

the lytic cycle only

Carrying capacity is ________.

the maximum population size that a particular environment can support

Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription?

the phosphate bonds in the nucleotide triphosphates that serve as substrates

In models of logistic population growth, ________.

the population growth rate slows dramatically as N approaches K

Cell differentiation always involves ________.

the production of tissue-specific proteins, such as muscle actin

If the DNA sequence was substantially altered from one of the following, which would prevent the binding of the TATA-binding protein (TBP)?

the promoter

Within a cell, the amount of protein made using a given mRNA molecule depends partly on ________.

the rate at which the mRNA is degraded

Which of the following is an example of post-transcriptional control of gene expression?

the removal of introns and alternative splicing of exons

The product of the lacI gene is ________.

the repressor

There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that ________.

the rules for base pairing between the third base of a codon and tRNA are flexible

What can proteomics reveal that genomics cannot?

the set of proteins present within a cell or tissue type

Imagine that there are 25 different species of protists living in a tide pool. Some of these species reproduce both sexually and asexually, and some of them can reproduce only asexually. The pool gradually becomes infested with disease-causing viruses and bacteria. Which species are more likely to thrive in the changing environment?

the sexually reproducing species

Which of the following is the first event to take place in translation in eukaryotes?

the small subunit of the ribosome recognizing and attaching to the 5' cap of mRNA

What cannot be determined from examining age pyramids of human populations?

the success of future generations

Global climate change refers to ________.

the sum of the changes in local precipitation and temperature patterns that result from global warming

Which of the following is directly related to a single amino acid?

the three-base sequence of mRNA

The mechanism for the spread of long interspersed nuclear elements (LINEs) involves some unique features, including ________.

the transport of mRNA from the cytoplasm to the nucleus

A bacterium was grown in two test tubes filled with media rich in glucose. One tube was sealed to produce anaerobic conditions, and the other was not. A third uninoculated, unsealed tube was used as a control. Glucose utilization by this bacterium causes acid production, which is indicated by a lightening of the media color. If the bacterium is able to produce ATP only by aerobic respiration, we expect lightening of media in ________.

the unsealed tube only

Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in ________.

their mode of nutrition

It is more difficult to identify eukaryotic genes than prokaryotic genes because in eukaryotes ________.

there are introns

In biology, an arms race occurs when ________.

there is a repeating cycle of coevolution

Molecular phylogenies show all land plants are a monophyletic group. This suggests ________.

there was a single transition from aquatic to terrestrial habitats

On which body segment are arthropod wings attached?

thorax

During gastrulation, ________.

three germ layers form

In humans, xeroderma pigmentosum (XP) is a disorder of the nucleotide excision repair mechanism. These individuals are unable to repair DNA damage caused by ultraviolet light. Which of the following are the most prominent types of DNA lesions in individuals suffering from xeroderma pigmentosum?

thymine dimers

Which of the following describe all existing bacteria?

tiny, ubiquitous, metabolically diverse

In E. coli, what is the function of DNA polymerase III?

to add nucleotides to the 3' end of a growing DNA strand

What is the goal of bioremediation?

to clean up areas polluted with toxic compounds by using bacteria

Knockout mice have been genetically altered to knock out specific genes. How are these mice most often used in research?

to determine the role of proteins coded for by those genes that are knocked out

People with at least one copy of the HLA-B53 gene are better able to beat back malarial infections before the infection progresses. If this is a coevolutionary arms race between Plasmodium and humans, what would the next step in this race be?

to see Plasmodium populations that counter the HLA-B53 gene

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily?

to serve as an outgroup

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

tortoiseshell females; black males

Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that ________.

traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1 generation

The functioning of enhancers is an example of ________

transcriptional control of gene expression

Gene expression in developing organisms is regulated on several different levels. In many developing animals, regulation of gene expression is influenced by the action of Hox genes. Which of the following regulatory elements is produced by many Hox genes?

transcriptional factors

Name two examples of lateral gene transfer to eukaryotes that involve cellular organelles.

transfer of bacterial genes that were predecessors to mitochondria and chloroplasts

If a scientist needs to put new DNA into a bacterium, she must ________ the bacterium.

transform

Some viruses can be crystallized and their structures analyzed. One such virus is yellow mottle virus, which infects beans. This virus has a single-stranded RNA genome containing about 6300 nucleotides. Its capsid is 25—30 nm in diameter and contains 180 identical capsomeres. If the yellow mottle virus begins its infection of a cell by using its genome as mRNA, which of the following would you expect to be able to measure?

translation rate

Once a peptide bond has been formed between the amino acid attached to the tRNA in the P site and the amino acid associated with the tRNA in the A site, what occurs next?

translocation

An adult animal that possesses bilateral symmetry would most likely be ________.

triploblastic

The feeding relationships among the species in a community determine the community's ________.

trophic structure

Homing pigeons' ability to always return to their home, no matter where they are released, is an excellent example of ________.

true navigation

Which of these are amniotes?

turtles

If x indicates the fossils of two closely related species, neither of which is extinct, then their remains may be found in how many of these strata?

two strata

The data collected by the researchers indicate that ________.

two-way migration of squirrels occurred across the bridge but without hybridization

Among protostomes, which morphological trait has shown the most variation?

type of body cavity (coelom vs. pseudocoelom vs. no coelom)

After looking at the experiment in the accompanying figure, what can be said about nutrient export in ecosystems? Nutrient export is ________.

typically 10 times higher in a clear-cut watershed

Which of the following most strongly supports the common origin of all life on Earth? All organisms ________.

use essentially the same genetic code

Viruses ________.

use the host cell to copy themselves and make viral proteins

Researchers discovered that a new strain of bacteria that cause tuberculosis (M. tuberculosis) taken from a dead patient has a point mutation in the rpoB gene that codes for part of the RNA polymerase enzyme. This mutant form of RNA polymerase does not function as well as the more common form of RNA polymerase. A commonly used antibiotic called rifampin does not affect the mutant rpoB bacteria. A researcher mixes M. tuberculosis with and without the rpoB mutation and adds the bacteria to cell cultures. Half the cell cultures contain only standard nutrients, while the other half of the cell cultures contain rifampin and the standard nutrients. After many cell generations, the researcher finds that ________.

very few M. tuberculosis in the standard nutrient cell cultures carry the rpoB gene mutation, but almost all of the M. tuberculosis in the cell cultures with rifampin carry the rpoB mutation

To assign absolute dates to fossils in this sediment core, it would be most helpful if ________.

volcanic ash layers were regularly interspersed between the sedimentary strata

In both lichens and mycorrhizae, what does the fungal partner provide to its photosynthetic partner?

water and minerals

What evidence do paleobotanists look for that indicates the movement of plants from water to land?

waxy cuticle to decrease evaporation from leaves

Suppose you came across a novel organism you suspected belonged to one of the following animal phyla: Porifera, Cnidaria, Ctenophora, or Acoela. Which of the following characteristics would NOT be helpful in placing the organism into the correct phylum?

whether the organism has a gut

Among the invertebrate phyla, phylum Arthropoda is unique in possessing members that have ________.

wings

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup?

wolf

Some fungi have been instrumental in the development of human culture, including __________ in the Phylum ________ as they have been in use for hundreds of years in producing beer and bread.

yeasts; Ascomycota

The symbols +, −, and 0 are to be used to show the results of interactions between individuals and groups of individuals in the examples that follow. The symbol + denotes a positive interaction, − denotes a negative interaction, and 0 denotes where individuals are not affected by interacting. The first symbol refers to the first organism mentioned. What interactions exist between a lion pride and a hyena pack?

−/−

A man has extra digits (six fingers on each hand and six toes on each foot). His wife and their daughter have a normal number of digits. Having extra digits is a dominant trait. The couple's second child has extra digits. What is the probability that their next (third) child will have extra digits?

1/2

Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation). What is the probability that their first child will be an albino?

1/4

In the cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?

1/64

Suppose two AaBbCc individuals are mated. Assuming that the genes are NOT linked, what fraction of the offspring are expected to be homozygous recessive for the three traits?

1/64

Assuming independent assortment for all gene pairs, what is the probability that the following parents, AABbCc × AaBbCc, will produce an AaBbCc offspring?

1/8

Approximately how many kilograms (kg) of carnivore (secondary consumer) biomass can be supported by a field plot containing 1000 kg of plant material?

10

Cinnabar eyes is a sex-linked, recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?

100 percent

Suppose researchers marked 800 turtles and later were able to trap a total of 300 individuals in that population, of which 150 were marked. What is the estimate for total population size?

1600

To measure the population of lake trout in a 250-hectare lake, 400 individual trout were netted and marked with a fin clip, then returned to the lake. The next week, the lake was netted again, and out of the 200 lake trout that were caught, 50 had fin clips. Using the mark-recapture estimate, the lake trout population size could be closest to which of the following?

1600

Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. If 1000 F2 offspring resulted from a dihybrid cross, approximately how many of them would you expect to have red, terminal flowers?

190

The oldest fossil remains of Homo sapiens found so far date from about ________.

195,000 years ago

When Mendel crossed yellow-seeded and green-seeded pea plants, all the offspring were yellow seeded. When he took these F1 yellow-seeded plants and crossed them to green-seeded plants, what genotypic ratio was expected?

1:1

Given a population that contains genetic variation, what is the correct sequence of the following events under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly-adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly-adapted individuals have decreased survivorship.

2 → 4 → 1 → 3

Put the following steps of DNA replication in chronological order. 1. Single-stranded binding proteins attach to DNA strands. 2. Hydrogen bonds between base pairs of antiparallel strands are broken. 3. Primase binds to the site of origin. 4. DNA polymerase binds to the template strand. 5. An RNA primer is created.

2, 1, 3, 5, 4

All arthropods ________. 1. undergo complete metamorphosis 2. have jointed appendages 3. molt 4. have segmented bodies 5. have an exoskeleton or cuticle

2, 3, 4, and 5

Assuming the existence of fossilized markers for each of the following chemicals, what is the sequence in which they should be found in this sediment core, working from ancient sediments to recent sediments? 1. chitin coupled with protein 2. chlorophyll 3. bone 4. cellulose

2, 4, 1, 3

Rank the following in order from most general to most specific: 1. gametic isolation 2. reproductive isolating mechanism 3. sperm-egg incompatibility in sea urchins 4. prezygotic isolating mechanism

2, 4, 1, 3

A pied kingfisher in its first year of life helps in the feeding of three full siblings who would not have made it without the helper's efforts. In this first year the bird does not raise any of its own offspring. In the second year of its life the pied kingfisher mates and raises two of its own offspring. After the first two years, what is the inclusive fitness of the pied kingfisher?

2.50

In rabbits, the homozygous CC is normal, Cc results in deformed legs, and cc results in very short legs. The genotype BB produces black fur, Bb brown fur, and bb white fur. If a cross is made between brown rabbits with deformed legs and white rabbits with deformed legs, what percentage of the offspring would be expected to have deformed legs and white fur?

25 percent

Imagine five forest communities, each with one hundred individuals distributed among four different tree species (W, X, Y, and Z). Which forest community would be most diverse?

25W, 25X, 25Y, 25Z

Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be ________.

28

In the accompanying phylogenetic trees, numbers represent species and the same species are shown in both trees. Which two species are represented as sister species in Tree 2 but are not shown as sister species in Tree 1?

3 and 4

Which of the following statements concerning animal taxonomy is (are) TRUE? 1. Animals are more closely related to plants than to fungi. 2. All animal clades based on body plan have been found to be incorrect. 3. Kingdom Animalia is monophyletic. 4. Animals only reproduce sexually. 5. Animals are thought to have evolved from flagellated protists similar to modern choanoflagellates.

3 and 5

Which two of the following have operated to increase divergence between mosquitofish populations on Andros? 1. improved gene flow 2. bottleneck effect 3. sexual selection 4. founder effect 5. natural selection

3 and 5

Arrange the following in the correct sequence, from earliest to most recent, in which these plant traits originated. 1. sporophyte dominance, gametophyte independence 2. sporophyte dominance, gametophyte dependence 3. gametophyte dominance, sporophyte dependence

3 → 1 → 2

A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be ________.

3' AAA-GAA-TAA-CAA 5'

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is ________.

3' UCA 5'

Put the following events of bacterial transcription in chronological order. 1. Sigma binds to the promoter region. 2. The double helix of DNA is unwound, breaking hydrogen bonds between complementary strands. 3. Sigma binds to RNA polymerase. 4. Sigma is released. 5. Transcription begins.

3, 1, 2, 5, 4

Using the accompanying life table, calculate the net reproductive rate (R0) for this population.

3.26

Approximately how far back in time does the fossil record extend?

3.5 billion years

Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. Among the F2 offspring of a dihybrid cross, what is the probability of plants with white axial flowers?

3/16

Given the parents AABBCc × AabbCc, assume simple dominance for each trait and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent with genotype AABBCc?

3/4

Different ratios occur in crosses with single gene pairs or two gene pairs. What types of ratios are likely to occur in crosses dealing with a single gene pair?

3:1, 1:1, 1:2:1

What interactions exist between a tick on a dog and the dog?

+/−

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

0

Consider the food chain of grass → grasshopper → mouse → snake → hawk. About how much of the chemical energy fixed by photosynthesis of the grass (100 percent) is available to the hawk?

0.01 percent

If 60 snow geese were alive in 1926 and 856 existed in 2001, what is r?

0.035

Approximately what percentage of the energy from sunlight is converted into gross primary production?

0.8 percent

In the figure, which number would designate the biome with the highest variation in annual precipitation?

1

Refer to the accompanying figure. Suppose new molecular analyses indicated that the phylum Annelida had diverged from the arthropod lineage after Onychophora and Tardigrada. What would this imply about protostome evolution? 1. Segmentation evolved only once within protostomes. 2. The annelid lineage gained and then lost the ability to molt. 3. The annelid lineage gained and then lost jointed limbs.

1 and 2

Fishes that have swim bladders can regulate their density and, thus, their buoyancy. There are two types of swim bladder: physostomous and physoclistous. The ancestral version is the physostomous version, in which the swim bladder is connected to the esophagus via a short tube (see the accompanying figure). The fish fills this version by swimming to the surface, taking gulps of air, and directing them into the swim bladder. Air is removed from this version by "belching." The physoclistous version is more derived and has lost its connection to the esophagus. Instead, gas enters and leaves the swim bladder via special circulatory mechanisms within the wall of the swim bladder. When a shark stops swimming, it ________. 1. sinks 2. quickly dies 3. oxygenates its blood less effectively

1 and 3

Put the following events of elongation in prokaryotic translation in chronological order. 1. Binding of mRNA with small ribosomal subunit 2. Recognition of initiation codon 3. Complementary base pairing between initiator codon and anticodon of initiator tRNA 4. Base pairing of the mRNA codon following the initiator codon with its complementary tRNA 5. Attachment of the large subunit

1, 2, 3, 5, 4

How many of the following are characteristics of at least some members of the phylum Cnidaria? 1. a gastrovascular cavity 2. a polyp stage 3. a medusa stage 4. cnidocytes 5. a pseudocoelom

1, 2, 3, and 4

According to the theory of sea-floor spreading, oceanic islands, such as the Hawaiian Islands depicted in the accompanying figure, form as oceanic crustal plates move over a stationary "hot spot" in the mantle. Currently, the big island of Hawaii is thought to be over a hot spot, which is why it is the only one of the seven large islands that has active volcanoes. What should be TRUE of the island of Hawaii? 1. Scientists in search of ongoing speciation events are more likely to find them here than on the other six large islands. 2. Its species should be more closely related to those of nearer islands than to those of farther islands. 3. It should have a rich fossil record of terrestrial organisms. 4. It should have species that are not found anywhere else on Earth. 5. On average, it should have fewer species per unit surface area than the other six islands.

1, 2, 4, and 5

The microsporidian Brachiola gambiae parasitizes the mosquito Anopheles gambiae. Adult female mosquitoes must take blood meals for their eggs to develop, and it is while they take blood that they transmit malarial parasites to humans. Male mosquitoes drink flower nectar. If humans are to safely and effectively use Brachiola gambiae as a biological control to reduce human deaths from malaria, then how many of the following statements should be TRUE? 1. Brachiola should kill the mosquitoes before the malarial parasite they carry reaches maturity. 2. The microsporidian should not be harmful to other insects. 3. Microsporidians should infect mosquito larvae, rather than mosquito adults. 4. The subsequent decline in anopheline mosquitoes should not significantly disrupt human food resources or other food webs. 5. Brachiola must be harmful to male mosquitoes but not to female mosquitoes.

1, 2, and 4

Which of the following are characteristics of arthropods? 1. protostome development 2. bilateral symmetry 3. a pseudocoelom 4. three embryonic germ layers 5. a closed circulatory system

1, 2, and 4

Which of the following reasons would explain why the sediment core lacks fossils of dragonflies with 3-foot wingspans? 1. This particular sediment core includes the correct stratum, but the part of the stratum captured by the core lacks such fossils. 2. The sea was not present at this site during the time that 3-foot dragonflies existed. 3. Dragonflies have no hard parts, such as exoskeletons, to fossilize. 4. The sediments containing these fossils at this site may have been eroded away during a time when the sea had receded from this site. 5. Dragonflies are terrestrial; therefore, fossils of terrestrial organisms should not be expected in the sediments of seas.

1, 2, or 4

Arrange the following structures, which can be found on male pine trees, from the largest structure to the smallest structure (or from most inclusive to least inclusive). 1. sporophyte 2. microspores 3. microsporangia 4. pollen cone 5. pollen nuclei

1, 4, 3, 2, 5

In the second year of its life a pied kingfisher mates and raises two of its own offspring. What is its direct fitness in this second year of its life?

1.00

A pied kingfisher in its first year of life helps in the feeding of three full siblings who would not have survived without the helper's efforts. What is its indirect fitness in its first year?

1.50

Radish flowers may be red, purple, or white. The part of the radish we eat may be oval or long. A cross between a red-flowered long radish plant and a white-flowered oval radish plant yields all-purple long radish offspring. Then the F1 are crossed. In the resulting F2 generation, which of the following phenotypic ratios would be expected?

6:3:3:2:1:1

In humans, male-pattern baldness may be assumed to be controlled by an autosomal gene that occurs in two allelic forms. Allele B determines nonbaldness, and allele b determines pattern baldness. In males, because of the presence of testosterone, allele b is dominant over B. If a man and woman both with genotype Bb have a son, what is the chance that he will eventually be bald?

75 percent

Using the accompanying figure, what is the predicted change in temperature under a model with continued very high emission of greenhouse gases?

7°C

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

8

Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. If doubly heterozygous SsNn cactuses were allowed to self-pollinate, the F2 would segregate in which of the following ratios?

9 sharp-spined:3 dull-spined:4 spineless

Using the accompanying figure, what is the predicted change in temperature under a model with dramatic reduction of greenhouse gases?

<1°C

Use the accompanying diagram of five islands formed at around the same time near a particular mainland, as well as MacArthur and Wilson's island biogeography principles, to answer the question(s) below. Which island would likely have the greatest species diversity?

A

Use the survivorship curves in the accompanying figure to answer the following questions. Referring to the figure, which curve best describes survivorship in elephants?

A

Which island would likely have the lowest extinction rate?

A

Which zone experiences the most abiotic change over a 24-hour period?

A

In an analysis of the nucleotide composition of DNA, which of the following will be found?

A + C = G + T

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?

A + G = C + T

Which of the following observations may have resulted in the hypothesis that a codon is made up of three bases?

A codon of three bases in length, from four different bases, would code for a maximum of sixty-four different amino acids.

What do we mean when we use the terms "monohybrid cross" and "dihybrid cross"?

A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied.

What is the main difference between a disturbance and a disturbance regime?

A disturbance regime includes defining the predictable frequency and severity of the disturbance

Which of the following examples describes a behavioral pattern that results from a proximate cause?

A female bird lays its eggs because the amount of daylight is decreasing slightly each day.

Which of the following is characteristic of the lytic cycle?

A large number of phages are released at a time.

Refer to the figure above. In their investigation of natural selection on Mc1r alleles (the gene that determines coat color) in Arizona pocket mice, Hoekstra et al. determined the frequency of the D and d alleles in each population. They also determined the frequency of alleles for two neutral mitochondrial DNA genes (genes that do not affect and are not linked to coat color). Why did the researchers include the mitochondrial DNA genes as part of their experimental design?

Allele change for the neutral mitochondrial genes serves as a control and gives information on any general background genetic difference among these populations.

Allolactose, an isomer of lactose, is formed in small amounts from lactose. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when lactose enters the cell?

Allolactose binds to the repressor protein

If the actual results most closely resembled those in part (A) in the figure above, then a further question arising from these data is: "Do the Dawsonia rhizoids have to be alive to reduce soil nitrogen loss, or do dead rhizoids have the same effect?" Arrange the following steps in the correct sequence to test this hypothesis. 1. Add metabolic poison to the soil of the experimental plot of mosses. 2. Apply water equally to the experimental and control plots. 3. Measure initial soil nitrogen contents of control and experimental plots. 4. Determine nitrogen loss from the soil of control and experimental plots. 5. Establish two identical plots of Dawsonia mosses; one as a control, the other as the experimental treatment.

5 → 3 → 1 → 2 → 4

At a specific area of a chromosome, the following sequence of nucleotides is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

5' A C G U U A G G 3'

A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?

5' TTT-CCC-AAA-GGG-TTT-CCC

Which of the following, if missing, would usually prevent translation from starting in eukaryotes?

5' cap or AUG codon

Use this representation to answer the following question. DNA template strand 5' ________ 3' DNA nontemplate strand3' ________ 5' Given the locally unwound double strand above, in which direction does the RNA polymerase move while transcribing DNA?

5' → 3' along the template DNA strand

If the sequence in the coding strand of DNA for a particular amino acid is 5'AGT3', then the anticodon on the corresponding tRNA would be ________

5'ACU3'

In tigers, a recessive allele causes a white tiger (absence of fur pigmentation). If one phenotypically normal tiger that is heterozygous is mated to another that is phenotypically white, what percentage of their offspring is expected to be white?

50 percent

When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?

50 percent

Cells were infected with approximately 1000 copies of either virus A or virus B at the 0 time point. At 5-minute intervals, a sample of the virus and cell mixture was removed. The intact cells were removed from the sample, and the number of viruses per milliliter of culture was determined. Using the data in the figure, how long does it take for virus B to go through one lytic cycle?

60 minutes

The protostome developmental sequence arose just once in evolutionary history, resulting in two main subgroups-Lophotrochozoa and Ecdysozoa. What does this finding suggest?

Division of these two groups occurred after the protostome developmental sequence appeared.

You are a forester charged with increasing productivity in a South American forest newly planted with pines from Oregon. You believe that the southern forest lacks the fungal diversity needed by the North American pines and that this lack of fungi is affecting the pines' productivity, but you have no evidence to support your ideas. To count how many fungal species were present in the Oregon forest, which methodology would you choose?

Do direct sequencing on representative soil samples from across the forest.

Which of the following is TRUE of the cloning experiment that resulted in Dolly the sheep?

Dolly was cloned by using a differentiated cell fused to an egg from another breed of sheep.

Where does tRNA #2 move to after this bonding of lysine to the polypeptide?

E site

Refer to the accompanying figure. Which of the following forms a monophyletic group?

E, F, and G

Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is TRUE?

Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted

One interesting and surprising finding regarding the regulation of the ara operon is that it is under both positive and negative control. What protein is responsible for the dual action of this operon?

AraC is responsible for both the positive and negative control of the ara operon

A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification?

Archaea

You are the lucky student of a wacky professor who develops a time machine. He asks if you will test it with him. You get in and there is an immediate glitch-the date readout fails so that when you land you are not sure what era you are in. As your time machine lands, you see an unusual landscape before you. As you open the door, you realize you cannot breathe. You quickly shut the door, realizing you are in the ________.

Archaean eon

Based on the data in the figure, which of the following statements is TRUE?

Area 1 could be called a tropical wet/rain forest.

Which of the following animal groups is entirely aquatic?

Echinodermata

Which of the following eukaryotic lineages contains species that all lack functioning mitochondria?

Excavata

In the accompanying figure, which of these countries has the highest per capita CO2 emissions?

Australia

In which habitat should one find snapping shrimp most closely related to shrimp that live in habitat A4?

B4

Refer to the study by Poulsen et al. and the accompanying figure. Cultures of a species of diatom were treated with BDM, a reversible inhibitor of myosin function. Which of the following predictions is consistent with the hypothesis that an actin-myosin interaction is necessary for motility?

BDM will significantly decrease motility of the cells in culture.

Prokaryotes are classified as belonging to two different domains. What are the domains?

Bacteria and Archaea

The accompanying graph shows data from a research study designed to test the hypothesis that both abiotic and biotic factors can affect the distribution of invasive Argentine ants. Using the graph, identify the statement that is best supported by the data.

Both abiotic and biotic factors interact to affect the distribution of invasive Argentine ants.

Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation and have one child out of three who is albino (without melanin pigmentation). What are the genotypes of the albino's parents?

Both parents must be heterozygous.

The accompanying graph shows data collected to test the hypothesis that the dewlap extension and the push-up displays of Anolis lizards play a role in sexual selection. Given this data, what can you conclude?

Both the dewlap extension and the push-up frequencies play a role in sexual selection.

Why does total biomass (graph e in the accompanying figure) not vary with AMF diversity?

Bromus erectus is the dominant plant species.

What is the major difference between Bromus erectus (graph f) and the other plant species (graphs a—d) included in the study?

Bromus erectus is unaffected by AMF diversity.

The following question(s) refer to the accompanying figure, which shows an outcrop of sedimentary rock whose strata are labeled A—D. If x indicates the location of fossils of two closely related species, then fossils of their most recent common ancestor are most likely to occur in which stratum?

C

Use the following tree to answer the question below. Which of the following trees, if any, depicts the same relationship among species as shown above?

C

Which graph properly depicts the relationship between the amount of gas in the swim bladder and the density of the fish? Graph with density on the x-axis and amount of gas in swim bladder on the y-axis. Both axes are unscaled, increasing. A line increases steeply from the origin and then flattens near the top of the y-axis.

C

Which island would likely exhibit the most impoverished species diversity?

C

Which letter represents an organism that could only be a primary consumer?

C

Which zone has a condition of constant temperature?

C

Why is Caenorhabditis elegans an appropriate model organism for studying developmental processes?

C. elegans is transparent and has only about 1000 cells, allowing the cells to be followed during development.

Compare the graphs in the accompanying figure of carbon dioxide (CO2) emission for Cormocephalus morsitans and Scutigerina weberi. What hypothesis can you make about each centipede's habitat?

C. morsitans lives in a drier habitat than does S. weberi.

Which of the following statements correctly describes a portion of the pine life cycle?

Female gametophytes use mitosis to produce eggs.

In all three species of phalarope, a taxon of wading shorebirds, the majority of parental care is provided by the male. Based on the Bateman-Trivers hypothesis of sexual selection, what would you expect to see in phalaropes?

Females are more brightly colored than males.

In the accompanying figure, which of the following conclusions is most logical based on the data?

Females produce more eggs faster when exposed to breeding males.

In Belding's ground squirrels, it is mostly the females that behave altruistically by sounding alarm calls. What is the likely reason for this distinction?

Females settle in the area in which they were born, so the alarm is more likely to warn kin.

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?

Calls would be more different in areas of sympatry.

Which listing of geological periods is in the correct order, from oldest to most recent?

Cambrian, Devonian, Permian, Cretaceous

Based on the graphs in the accompanying figure, which of the following plant species is most likely NOT to form mycorrhizal associations?

Carex flacca (graph a)

Bacterial and eukaryotic cells primarily control gene expression at the level of transcription. If instead cells exerted control of gene expression primarily at the post-translational level, what would be different?

Cells would expend significantly more energy

In the accompanying figure, which of these countries has the highest total CO2 emissions?

China

In examining a protist, you notice that it lacks a cell wall, and has movement with cytoplasmic streaming. These data allow you to infer that the species belongs to which of the following protist groups?

Amoebozoa

There are 61 codons that each specify the addition of a specific amino acid, and 3 stop codons for which there is no corresponding amino acid. However, there are only about 40 tRNA molecules, representing 40 anticodons. How is that possible?

An anticodon forms hydrogen bonds with the codon; it must match the first two bases of the codon but is less specific with respect to the third base.

Whiteflies are common pest insects found on cotton, tomato, poinsettia, and many other plants. Nymphs are translucent and mostly sessile, feeding on their host plants' phloem (sap) from the undersides of leaves. They undergo incomplete metamorphosis into winged adults. Because whitefly nymphs cannot escape predation by moving, you hypothesize that their translucent bodies make them hard to spot by predators. How could you directly test this hypothesis?

Compare rates of predation on whitefly nymphs coated with a nontoxic dye vs. undyed whitefly nymphs.

The question(s) below refer to the following table, which compares the % sequence homology of four different parts (two introns and two exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (for example, Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A. Based on the tabular data, and assuming that time advances vertically, which phylogenetic tree is the most likely depiction of the evolutionary relationships among these five species?

D

If you wanted to prevent a regulatory protein from changing gene expression, you would have to prevent physical contact between the protein and ________.

DNA

Genotype is to ________ as phenotype is to ________.

DNA base sequence; physical traits that are products of the proteins produced

Which piece of evidence supports the hypothesis shown in the "Within the artiodactyls" origin of the whale lineage, suggesting that the whale lineage diverged from the lineage leading to the hippos after the other members of the order Artiodactyla (pigs, camels, etc.) diverged?

DNA comparisons show that whales and hippos share more genetic sequences than whales share with other artiodactyls.

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

DNA contains phosphorus, whereas protein does not.

For applications in gene therapy, what is the most favorable characteristic of retroviruses?

DNA copies of retroviral genomes become integrated into the genome of the infected cell.

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

DNA in both daughter cells would be radioactive.

Two potential devices that eukaryotic cells use to regulate transcription are ________.

DNA methylation and histone modification

DNA contains the template needed to copy itself, but it has no catalytic activity in cells. What catalyzes the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed?

DNA polymerase

If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, starting from phytoplankton to zooplankton to fish to seals to polar bears, then which of the following could be TRUE?

Fish can potentially provide more food for humans than seal meat.

Which of the following features of how seedless land plants get sperm to egg are the same as for some of their algal ancestors?

Flagellated sperm swim to the eggs in a water drop

Which of the following statements is TRUE of histones?

Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together.

Why do histones bind tightly to DNA?

Histones are positively charged, and DNA is negatively charged

Which of the following is most critical for the association between histones and DNA?

Histones are positively charged.

Which of these species is currently thought to have coexisted for 35,000 years or more (at the same time and places) with H. neanderthalensis?

Homo sapiens

Which of these species had members who moved out of Africa?

Homo sapiens and Homo erectus

Which of the following is consistent with the out-of-Africa hypothesis?

Homo sapiens have a common ancestor with Neanderthals and Homo erectus from Africa.

Looking at the data in the accompanying figure from the hare/lynx experiment, what conclusion can you draw? I. Food is a factor in controlling hare population size. II. Excluding lynx is a factor in controlling hare population size. III. The effect of excluding predators and adding food in the same experiment is greater than the sum of excluding lynx alone plus adding food alone.

I, II, and III

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related but separate species of tree frogs in South America. What outcomes could possibly occur where the ranges of two species overlap? I. The species will interbreed, eventually fusing over time. II. A stable hybrid zone will form if hybrids are better adapted to the area of overlap than either parent species is. III. Species will continue to diverge and be isolated by behavioral or genetic mechanisms.

I, II, and III

Scientists believe that the direction birds go when migrating is guided in part by ________. I. the stars in the night sky II. the Sun during the day III. the magnetic field of the Earth

I, II, and III

The vegetative (nutritionally active) bodies of most fungi are ________. I. composed of hyphae II. referred to as a mycelium III. usually underground

I, II, and III

Which of the following are negative biological consequences of climate change? I. changes in geographic ranges II. changes in phenology III. extinctions

I, II, and III

Which of the following are responsible for generating successional pathways? I. species interactions II. historical and environmental context III.species traits

I, II, and III

Which of the following have contributed to the increase in the emission of CO2? I. increases in human population II. increases in per capita fossil-fuel use III. land use changes

I, II, and III

Which of the following would be useful in creating a phylogenetic tree of a vertebrate taxon? I. morphological data from fossil species II. genetic sequences from living species III. behavioral data from living species

I, II, and III

Which of the three types of viruses shown in the accompanying figure has a capsid?

I, II, and III

Which value(s) would be required to calculate how long ago the most recent ancestor of ungulates lived? I. the number of base pairs that differ among species in a certain genetic sequence II. the total number of base pairs in the genetic sequence examined III. the age of a fossil ancestor for calibration

I, II, and III

A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species, each of which eats only a certain type of food. None of the species can fly and their balancing organs (halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap. Fly species W, found in a certain part of the island, produces fertile offspring with species Y. Species W does not produce fertile offspring with species X or Z. If no other species can hybridize, then which of the following statements about species W and Y is/are TRUE? I. Species W and Y have genomes that are still similar enough for successful meiosis to occur in hybrid flies. II. Species W and Y have more genetic similarity with each other than either did with the other two species. III. Species W and Y may fuse into a single species if their hybrids remain fertile over the course of many generations.

I, II, and III are correct.

Bioinformatics includes ________.I. using computer programs to align DNA sequences II. creating recombinant DNA from separate species III. developing computer-based tools for genome analysis IV. using mathematical tools to make sense of biological systems

I, III, and IV

Cycads, a mostly tropical phylum of gymnosperms, evolved about 300 million years ago and were dominant forms during the Age of the Dinosaurs. Though their sperm are flagellated, their ovules are pollinated by beetles. These beetles get nutrition by eating pollen and microsporophyll tissue and shelter within the male cones (they are dioecious). Upon visiting megasporophylls on nearby female plants, which become attractively aromatic and warm (but are not palatable), the beetles transfer pollen to the exposed ovules. Cycad megasporophyll tissues synthesize neurotoxins, some of which is transferred to the seeds, that are effective against most animals, including humans. Which feature of cycads distinguishes them from most other gymnosperms? I. They have exposed ovules. II. They have flagellated sperm. III. They are pollinated by animals.

II and III

Harold and Kumar are pre-med and pre-pharmacy students, respectively. They complain to their biology professor that they should not have to study about plants because plants have little relevance to their chosen professions. Which adaptations of land plants are likely to provide Harold with future patients? I. sporophyte dominance II. defenses against herbivory III. adaptations related to wind dispersal of pollen

II and III

Which tree depicts the microsporidians as a sister group of the fungi, rather than as a fungus?

IV

You just discovered a new virus. This virus infects heart muscle, where it causes inflammation, and has a very high mutation rate. Which of the following is the best strategy for finding a treatment for this virus?

Identify the receptor this virus uses and develop an enzyme that blocks the receptor.

Based on the idea that fungi have pores between their cell walls, which allow cytoplasm to move from one end of the mycelium to the other, which of the following hypotheses is the most plausible?

If a single mycorrhizal fungus formed symbiotic associations with more than one tree, carbon could travel from one plant to another.

Swine are vulnerable to infection by bird flu virus and human flu virus, which can both be present in an individual pig at the same time. When this occurs, it is possible for genes from bird flu virus and human flu virus to be combined. If the human flu virus contributes a gene for Tamiflu resistance (Tamiflu is an antiviral drug) to the new virus, and if the new virus is introduced to an environment lacking Tamiflu, then what is most likely to occur?

If the Tamiflu-resistance gene involves a cost, it will experience directional selection leading to reduction in its frequency.

When many genes of an organism are globally regulated, those genes are considered as regulon genes. What is the common theme of such genetic regulation?

Genes of regulons are silenced by a common repressor.

Which statement best describes the evolutionary significance of mutualism?

Interaction increases the survival and/or population growth rate(s) of mutualistic species.

Two species of tree frogs that live sympatrically in the northeastern United States differ in ploidy: Hyla chrysoscelis is diploid, and Hyla versicolor is tetraploid. The frogs are identical in appearance, but their mating calls, which females use to find mates, differ. Which likely evolved first?

Polyploidy

Assuming that these populations are density dependent, what would be the likely outcome if the system depicted in the previous figure were allowed to continue?

Population growth would likely decrease.

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called ________

RNA interference

In the process of transcription, ________.

RNA is synthesized

In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein?

RNA polymerase II

It has been hypothesized that fungi and plants have a mutualistic relationship because plants make sugars available for the fungi's use. What is the best evidence in support of this hypothesis?

Radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated.

During a one-year study, researchers found no difference in treehopper populations in any of their control and experimental groups. What could they measure during the second year to gain information about why this might have occurred?

Measure the relative abundance of jumping spiders.

Which of the following is the meaning of the chromosome theory of inheritance as expressed in the early twentieth century?

Mendelian genes are at specific loci on the chromosome and, in turn, segregate during meiosis.

Who performed classic experiments that supported the semiconservative model of DNA replication?

Meselson and Stahl

Once researchers identified DNA as the unit of inheritance, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. What is the mechanism of information transfer in eukaryotes?

Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place.

Which of the following is TRUE?

Mutations that inactivate tumor suppressor genes are important in cancer.

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Instead, DDT is largely useless against many insects. Which of these would have prevented this evolution of DDT resistance in insect pests?

None of the insect pests would have genetic variations that resulted in DDT resistance.

There is a mutation in the repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of these would characterize such a mutant?

It cannot bind to the inducer.

How does the enzyme telomerase meet the challenge of replicating the ends of linear chromosomes?

It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity.

Which of the following is the best explanation for the high degree of sequence homology observed in Exon I among these five species?

It codes for a polypeptide domain that has a crucial function.

How does solar radiation (per unit area) vary with latitude?

It decreases.

Why doesn't inbreeding depression, by itself, cause evolution?

It does not change the population's allele frequencies.

You discover a new species of protist. Which of the following characteristics would provide the strongest evidence for your hypothesis that your species belongs in Euglenida?

It has a pellicle just under the plasma membrane.

You find what you believe is a new species of animal. Which of the following characteristics would enable you to argue that it is more closely related to a flatworm than it is to a roundworm?

It has no coelom.

You are a physician and you suspect your patient has a viral infection that has never been seen in humans. The infection is localized in the cells along the lining of the small intestine. The cells in this area are regularly sloughed off and replaced with new cells; that is, these cells are constantly dividing. When you isolate this new virus and incubate it in culture, you discover that it does not replicate well in cultures that have slowly dividing cells, but it does much more damage in cultures that have actively dividing cells. What do these findings suggest about this new virus?

It is a double-stranded DNA virus.

A female cat in heat urinates more often and in many places. Male cats are attracted to the urine deposits. Which of the following is a proximate cause of this increased urination?

It is a result of hormonal changes associated with her reproductive cycle

You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium?

It is able to form colonies and produce oxygen

What is TRUE about the genus Sphagnum?

It is an important carbon sink, reducing atmospheric carbon dioxide.

Which statement best describes what ultimately happens to the chemical energy that is NOT converted to new biomass in the process of energy transfer between trophic levels in an ecosystem?

It is eliminated as feces or is dissipated into space as heat, consistent with the second law of thermodynamics.

If the accompanying figure shows the dances of bees in a hive at twelve noon on March 21 in the northern hemisphere, which dance is communicating that the food is to the south of the hive?

It is not possible to tell if any of the dances indicate the food is to the south of the hive.

By examining the phylogenetic tree diagrammed in the accompanying figure, what conclusion can you draw about the species G. microti?

It is part of a monophyletic group that also includes G. intestinalis

Which of the following statements about the DNA in one of your brain cells is TRUE?

It is the same as the DNA in one of your heart cells.

Look at the evolutionary relationship of protein kinases in the figure. Knowing that there is evidence that this particular protein kinase is linked to food-related behaviors in the animals studied, what conclusions can you draw?

PKG influences food-related behaviors in a wide variety of animals, and there is likely a conserved evolutionary relationship between these genes and their behavioral phenotype.

You isolate a cell infected with an adenovirus. What are you most likely going to see when you examine the cell?

It is undergoing mitosis.

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

It joins Okazaki fragments together.

You believe that an adult animal you are examining is a vertebrate but concede that it may be an invertebrate chordate. Which of the following would ensure that you are indeed looking at a vertebrate?

It lacks a notochord.

Which of the following lines of evidence would best support your assertion that a particular plant is an angiosperm?

It lacks gametangia.

How did the evolution of the jaw contribute to diversification of early vertebrate lineages?

It made additional food sources available.

Why might a point mutation in DNA make a difference in the level of a protein's activity?

It might substitute a different amino acid in the active site

What is the function of the group of amino acids on the RNA polymerase, called the rudder?

It moves template and non-template strands of DNA through channels inside the enzyme.

What must be TRUE of any organ described as vestigial?

It must be homologous to some feature in an ancestor.

On the back of your skull you can feel a small bump, below which is an opening where the spinal cord enters the skull. The location of this opening toward the bottom of the skull is significant in evolutionary biology for what reason?

It occurred as a result of the change to a bipedal stance.

You find a new species of worm and want to classify it. Which of the following lines of evidence would allow you to classify the worm as a nematode and not an annelid?

It sheds its external cuticle to grow.

What is the function of reverse transcriptase in retroviruses?

It uses viral RNA as a template for DNA synthesis.

Which statement is TRUE with regard to human population growth?

Its rate of growth is slowing

Often the growth cycle of one population has an effect on the cycle of another. As moose populations increase, for example, wolf populations also increase. Thus, if we are considering the logistic equation for the wolf population, ΔN/Δt = rN*(k-n)/k , which of the factors accounts for the effect of the moose population?

K

Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate-zone lakes?

Water is densest at 4°C.

Which of the following can be said about light in aquatic environments?

Water selectively reflects and absorbs certain wavelengths of light.

In plant communities today, leaf morphology is correlated with mean annual temperature, so paleobotanists use fossil leaf morphology to estimate the mean annual temperature of paleoclimates. However, the angiosperm fossil record contains an overabundance of samples fossilized near lakes or rivers where vines are especially common. Since vine leaves have a somewhat different association with temperature, use of data from vine-rich locations leads to mean average temperature estimates that are lower than actual recorded temperatures in modern plant communities. This potential bias in paleobotanical climate estimates is due to which type of bias in the fossil record? (R. J. Burnham, N. C. A. Pitman, K. R. Johnson, and P. Wilf. 2001. Habitat-related error in estimating temperature from leaf margins in a humid tropical forest. American Journal of Botany 88:1096—1102.)

habitat bias

What is still lacking in the hypothesis of an asteroid impact as the cause of the endCretaceous mass extinction?

a complete explanation of why some lineages survived while others vanished

In your laboratory, you examine a vial of freshwater from a local pond. You notice several unfamiliar small (less than 1 millimeter in length) animals and decide to study them. You observe that the animals have a coelom, eat microscopic food particles, reproduce by parthenogenesis, and have offspring that do not undergo any larval stages. What else would you expect to observe about this organism?

a corona

The DNA of telomeres has been highly conserved throughout the evolution of eukaryotes. This most likely reflects ________.

a critical function of telomeres

Which of the following is most likely to have a small protein called ubiquitin attached to it?

a cyclin protein, which usually acts in G1, in a cell that is in G2

Which of the following might be a result of adding a secondary consumer to the aquatic ecosystem in the accompanying illustration?

a decrease in the number of primary consumers

Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?

a deletion of two nucleotides

Nematode worms and annelid worms share which of the following features?

a digestive tract with two openings (a mouth and an anus)

Which type of disorder is most difficult to correct by gene therapy?

a dominant disorder

A recent study compared the Homo sapiens genome with that of Neanderthals. The results of the study indicated a mixing of the two genomes at some period in evolutionary history. Additional data consistent with this hypothesis could be the discovery of ________.

a few modern H. sapiens with some Neanderthal sequences

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

habitat isolation

Use the following information to answer the question(s) below. Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. What keeps the two populations separate?

habitat isolation

About 450 million years ago, the terrestrial landscape on Earth would have ________.

had non-vascular green plants similar to liverworts forming green mats on rock

In plants, which of the following are produced by meiosis?

haploid spores

Which of the following types of mutation would convert a proto-oncogene into an oncogene?

a mutation that greatly increases the amount of the proto-oncogene protein

Vertebrates and tunicates share ________.

a notochord and a dorsal, hollow nerve cord

Terry takes the body of the snakelike organism and slices it open along its dorsal side. If it is a hagfish, what should Terry see?

a notochord, located underneath the spinal cord

In recombinant DNA methods, the term "vector" can refer to ________.

a plasmid used to transfer DNA into a living cell

Which of the following organisms would you expect to have the largest surface-area-tovolume ratio? Assume that all of the following are the same total length.

a platyhelminth

Microsporidians are considered parasitic because of the ability to penetrate their host cells using ________.

a polar tube

What is responsible for termination of transcription in eukaryotic protein-coding genes?

a polyadenylation, or poly(A), signal

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in ________.

a polypeptide missing an amino acid

Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna?

hard parts

Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships? The fossil record reveals an increased incidence of ________.

hard parts

If you say that a ground squirrel has greater evolutionary fitness than another ground squirrel in the same population, you mean that the animal

has more offspring that survive and reproduce themselves.

Sponges ________.

have larvae which are motile and move via the motion of cilia

Because they are morphologically simple, Psilotophyta (whisk ferns) have traditionally been thought to be a basal group in the radiation of land plants. Molecular phylogenies have challenged this hypothesis and support the alternative hypothesis that they________.

have lost complex structures in this lineage

As climate changes because of global warming, plant species' ranges in the northern hemisphere may move northward. The trees that are most likely to avoid extinction in such an environment are those that ________.

have seeds that are easily dispersed by wind or animals

Unlike eutherians, both monotremes and marsupials ________.

have some embryonic development outside the uterus

A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts ________.

have three or four membranes

When people die from HIV infections, it is usually because they ________.

have too few T cells to adequately fight infection

If you were to observe the activity of methylated DNA, you would expect it to ________.

have turned off or slowed down the process of transcription

Dinoflagellates ________.

have walls that are usually composed of cellulose plates

You are the lucky student of a wacky professor who develops a time machine. He asks if you will test it with him. You get in and there is an immediate glitch-the date readout fails so that when you land you are not sure what era you are in. Your professor begins to panic, but you see something that tells you are in the Cenozoic era. Which of the following could it be?

a rabbit eating a daisy

The body cavity type for arthropods and mollusks can best be described as ________.

a reduced coelom

Which of the following would you expect of a eukaryote lacking telomerase?

a reduction in chromosome length in gametes

In negative control, a gene is switched off when ________.

a regulatory protein binds to DNA and shuts down transcription

Sequencing an entire genome, such as that of C. elegans, a nematode, is most important because ________.

a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates

Imagine that you are studying the control of β-globin gene expression in immature red blood cells. (Mature red blood cells contain β-globin protein but lack a nucleus and, therefore, the βglobin gene.) If you deleted a sequence of DNA outside the protein-coding region of the β-globin gene and found that this increased the rate of transcription, the deleted sequence likely functions as ________.

a silencer

Which of the following statements describes a eukaryotic chromosome?

a single linear molecule of double-stranded DNA plus proteins

Which of the following mutations is likely to cause the most dramatic phenotypic change?

a single nucleotide deletion in an exon coding for an active site

Which of the following mutations is most likely to cause a phenotypic change?

a single nucleotide deletion in an exon coding for an active site

Which of the following mutations would be most likely to have a harmful effect on an organism?

a single nucleotide insertion downstream of, and close to, the start of the coding sequence

Arthropod exoskeletons and mollusk shells both ________.

help retain moisture in terrestrial habitats

During elongation, RNA polymerase has three prominent channels, or grooves. These channels provide sites for all of the following EXCEPT ________.

a site for the exit of the diphosphates removed from the nucleotide triphosphates

Most cnidarians are known to produce toxins. In fact, it has been claimed that one particular species produces the most deadly of all toxins on the planet. What feature of this group most likely evolved simultaneously with the evolution of these toxins?

a slow-moving or sessile lifestyle in the adult

The largest unit within which gene flow can readily occur is ________.

a species

Which of the following could be considered the most recent common ancestor of living tetrapods?

a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates

Which of the following statements best describes the term synapomorphy?

a trait common in a single monophyletic group but not generally found outside of that group

Which of the following nucleotide triplets best represents a codon?

a triplet in the same reading frame as an upstream AUG

Upon being formed, oceanic islands, such as the Hawaiian Islands, should feature what characteristic, leading to which phenomenon?

a variety of empty ecological niches, leading to adaptive radiation

Many crustaceans (for example, lobsters, shrimp, and crayfish) use their tails to swim, but crabs have reduced tails that curl under their shells and are not used in swimming. This is an example of ________.

a vestigial trait

One of the fish in your aquarium dies. Adding which protist to the water would allow you to avoid flushing the dead fish by speeding its decay?

a water mold

Which of the following characteristics are shared by hagfish and lamprey?

a well-developed notochord

Predict what you would see if you were looking at a new species of Zygomycetes.

a zygote enclosed in a tough outer coat

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae. A P. bursaria cell that has lost its zoochlorellae is said to be aposymbiotic. It might be able to replenish its contingent of zoochlorellae by ingesting them without subsequently digesting them. Which of the following situations would be most favorable to the reestablishment of resident zoochlorellae, assuming compatible Chlorella are present in P. bursaria's habitat?

abundant light, abundant bacterial prey

Use the following information to answer the question below. In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20 percent of the β hemoglobin alleles in the human gene pool. The sickle-cell allele is pleiotropic (that is, it affects more than one phenotypic trait). Specifically, this allele affects oxygen delivery to tissues and affects one's susceptibility to malaria. Heterozygous individuals who have one normal and one sickle-cell allele have a phenotype that has both costs and benefits. The cost: Under conditions of low atmospheric oxygen availability, individuals heterozygous for this allele can experience life-threatening sickle-cell "crises." The benefit: Such individuals are less susceptible to malaria. Thus, pleiotropic genes/alleles reveal that ________.

adaptations are often compromises

Ichthyosaurs, now extinct, were aquatic reptiles with dorsal fins and tails, similar to those of fish. Their most recent ancestors were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are ________.

adaptations to a common environment and examples of convergent evolution

Whatever its ultimate cause(s), the Cambrian explosion is a prime example of ________.

adaptive radiation

Using the life table, determine which age class year would hurt the population growth most if it were wiped out by disease.

age class year 1

Adult tunicates (urochordates) lack notochords, however, larval urochordates have them and use them to ________.

aid in swimming; adults are sessile and thus no longer propel themselves

Which category in the figure makes available the highest productivity per square meter?

algal beds and reefs

Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce ________.

all sharp-spined progeny

House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of ________.

allopatric speciation

Which process led to the formation of the species pairs of Pacific and Caribbean snapping shrimp?

allopatric speciation by vicariance

How are two different species most likely to evolve from one ancestral species?

allopatrically, after the ancestral species has split into two populations

Jacob and Monod were intellectually primed to draw the conclusions they did concerning regulation of the lac operon. In part, this was due to their fascination with mechanisms of enzyme regulation. They knew that the activity of some enzymes is regulated when their reaction product binds to the enzyme, changing its shape and, therefore, its activity. This knowledge allowed them to easily make the intellectual leap to propose ________.

allosteric regulation of the repressor

How would a terrestrial centipede most likely benefit from the ability to close its spiracles? Closing spiracles would ________.

allow the centipede to retain more moisture in its tissues

DNA microarrays have made a huge impact on genomic studies because they ________.

allow the expression of many or even all of the genes in the genome to be compared at once

Altering patterns of gene expression in prokaryotes would most likely serve an organism's survival by ________.

allowing an organism to adjust to changes in environmental conditions

Red, brown, and some green algae exhibit alternation of generations. All land plants exhibit alternation of generations. No charophytes (stoneworts) exhibit alternation of generations. Keeping in mind the recent evidence indicating charophytes are the sister group to land plants, we can infer ________.

alternation of generations likely evolved independently in land plants as well as in red and brown algae

Which of the following allows more than one type of protein to be produced from one gene?

alternative forms of RNA splicing

An E. coli cell without a functional lacI gene is expected to ________.

always produce β-galactosidase

Which of the following is NOT synthesized from a DNA template?

amino acids

A ribozyme is ________.

an RNA with catalytic activity

Which of the following viruses would most likely have reverse transcriptase?

an RNA-based lysogenic virus

Suppose, while out camping in a forest, you found a chordate with a long, slender, limbless body slithering across the ground near your tent. This critter could be ________.

an amphibian

Which of the following extremophiles might researchers most likely use as a model for the earliest organisms on Earth?

an anaerobic archaean species

A hybrid zone is properly defined as ________.

an area where mating occurs between members of two closely related species, producing viable offspring

When bone tissue first evolved in vertebrates, it was found within ________.

an exoskeleton

The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to ________.

an extensive surface area well suited for invasive growth and absorptive nutrition

The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and ________.

an increasing number of viable, fertile hybrids is produced over the course of the next 100 generations

If you are interested in observing a relatively simple community structure in a clear-water lake, you would do well to choose diving into ________

an oligotrophic lake

A terrestrial animal species is discovered with the following larval characteristics: exoskeleton, system of tubes for gas exchange, and modified segmentation. A knowledgeable zoologist should predict that the adults of this species would also feature ________.

an open circulatory system

Suppose several genes are grouped together in a bacterial genome and the group results in a single enzyme. If one of these genes is mutated and the enzyme is no longer active, this gene must be part of ________.

an operon

Which of the following has a coefficient of relatedness of 0.25? Assume all are blood relatives

an uncle to his nephew

All of the following events can trigger an adaptive radiation EXCEPT ________.

an unusual event splitting a habitat, such as a severe hurricane

Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?

anaphase I of meiosis

When we compare animal development to plant development, we find that ________

animal cells, but not plant cells, migrate during morphogenesis

When we compare animal development to plant development, we find that ________.

animal cells, but not plant cells, migrate during morphogenesis

Among the organisms listed here, which are thought to be the closest relatives of fungi?

animals

The protein of the bicoid gene in Drosophila determines the ________ of the embryo.

anterior—posterior axis

Chemicals, secreted by soil fungi, which inhibit the growth of bacteria, are known as ________.

antibiotics

Viral envelopes can best be analyzed with which of the following techniques?

antibodies against specific proteins not found in the host membranes

Which marine zone would have the lowest rates of primary productivity (photosynthesis)?

aphotic

Which of the following is NOT a producer?

apicomplexan

During metamorphosis, a tadpole's tail is reduced in size by the process of ________.

apoptosis

Dll is a gene known to direct limb development in the fruit fly. Researchers studying this gene have found that it is also expressed in developing appendages in animals from many other phyla, supporting the hypothesis that all animal appendages may be homologous. However, suppose researchers looking at Dll activity had instead found the results shown in the preceding table. These results suggest instead that ________.

appendages evolved separately in protostomes and deuterostomes

What group of fungi has the ability to penetrate its host's cell wall, thus increasing the efficiency with which materials are passed from fungus to host?

arbuscular mycorrhizal fungi

Choanoflagellates ________.

are a sister group to animals

Fungi with hyphae ________.

are adapted for rapid directional growth to new food sources

The primary difference between enhancers and promoter-proximal elements is that enhancers ________.

are at considerable distances from the promoter; promoter-proximal elements are close to the promoter

As fuels, wood and coal ________.

are both formed from living or fossil plants.

Which of the following is TRUE of innate behaviors? Innate behaviors ________.

are expressed in most individuals in a population

Using the figure and the accompanying paragraph, and knowing that the PKG encoded by the foraging gene has recently been associated with the maturation of out-of-nest behavior in honeybees, what would be a logical explanation for this relationship? As animals mature, they ________.

are more likely to forage; therefore, PKG levels must increase.

All sponges ________.

are sessile and benthic as adults

Animals that help other animals of the same species ________.

are usually related to the other animals helped

The protein p53 activates genes that ________.

arrest the cell cycle

In the accompanying figure, which of the arrows represents the most rapid population growth?

arrow B

In the accompanying figure, which of the arrows represents the carrying capacity?

arrow C

Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that ________.

arthropods have had more time to coevolve with land plants than have vertebrates

Over human history, which process has been most important in improving the features of plants long used by humans as staple foods?

artificial selection

Species richness increases ________.

as we travel southward from the North Pole

You are given an organism to identify. It has a fruiting body that contains many structures with eight haploid spores lined up in a row. What kind of a fungus is this?

ascomycete

The sporangia of the bread mold Rhizopus are ________.

asexual structures that produce haploid spores

Bacteria able to perform the NH4+ + NO2− → N2 + 2H2O reaction have been discovered in laboratory bioreactors and wastewater treatment systems. Researchers predicted that these bacteria should exist in oceans. They measured the concentration of NH4+, NO2−, NO3−, and O2 in the Black Sea as a function of water depth (M. Kuypers et al. 2003 Anaerobic ammonium oxidation by anammox bacteria in the Black Sea. Nature 422:608—11) to determine where in the sea the bacteria might live. By analyzing data presented in the accompanying figure, at what depth would you expect to find the bacteria? (Note: In the figure, different scales are used to show concentrations of NH4+, NO2−, NO3−, and O2.)

at a depth of 92 meters

When the spliceosome binds to the transcript shown above, it can attach ________.

at certain sites along an intron

For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and energy are similar in that they have a broad base and a narrow top. The primary reason for this pattern is that ________.

at each step, energy is lost from the system

Consider the global water cycle depicted in the accompanying figure. Which one of the reserves contains the smallest percentage of global water?

atmosphere

Which of the following locations is the main reservoir for nitrogen in the nitrogen cycle?

atmosphere

In temperate lakes, the surface water is replenished with nutrients during turnovers that occur in the ________.

autumn and spring

Why do skates and rays have flattened bodies, while sharks are torpedo shaped?

Sharks are streamlined for active swimming off the bottom; skates move about mostly on the ocean bed

The ribosome-binding site of prokaryotes is also known as the ________.

Shine—Dalgarno sequence

Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees?

Similarity due to common ancestry should be more common than similarity due to convergent evolution.

In the traditional morphological phylogeny (A), the phylum Platyhelminthes is depicted as a sister taxon to the rest of the protostome phyla and as having diverged earlier from the lineage that led to the rest of the protostomes. In the molecular phylogeny (B), Platyhelminthes is depicted as a lophotrochozoan phylum. What probably led to this change?

Similarity of genetic information has led to realization that some morphological features are evolutionarily flexible (e.g., coelom formation) and so cannot be used as a diagnostic character.

Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?

Simple morphologies convey some advantages in most parasites.

Which of the following is a correct statement about the MacArthur/Wilson Island Biogeography Model?

Small islands receive few new immigrant species.

According to the lac operon model proposed by Jacob and Monod, what is predicted to occur if the operator is removed from the operon?

The lac operon would be transcribed continuously.

Pea aphids (Acyrthosiphon pisum) are the only animals able to synthesize their own carotenoid pigments, due to lateral gene transfer from the genome of a fungus to the genome of a recent ancestor of the pea aphids. The resulting red or green coloration alters the risk the aphids face from specific predators and parasites. Select the correct statement below.

The lateral transfer of genes for carotenoid synthesis from a fungus to an aphid is a form of mutation.

Which of the following statements about independent assortment and segregation is correct?

The law of independent assortment requires describing two or more genes relative to one another.

Which of the following could be a vicariance event?

The level of water in a lake recedes, creating two lakes where there used to be one.

Imagine that you have isolated a yeast mutant that contains a constitutively (constantly) active histone deacetylase. What phenotype do you predict for this mutant?

The mutant will show low levels of gene expression

Imagine that you've isolated a yeast mutant that contains histones resistant to acetylation. What phenotype do you predict for this mutant?

The mutant will show low levels of gene expression

Upon close inspection of movement in annelids and nematodes, you would notice an obvious difference. Nematodes tend to wriggle back and forth, while annelids tend to contract along their length as their girth swells and then thin out as they stretch. What anatomical feature explains this type of movement?

The nematodes lack circular muscle fibers.

What characteristic of short tandem repeats (STRs) DNA makes it useful for DNA fingerprinting?

The number of repeats varies widely from person to person or animal to animal.

All things being equal, which of these is the most parsimonious explanation for the change in the number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in the table above?

The occurrence of a single duplication of the entire seven-gene cluster.

The herpes viruses are important enveloped DNA viruses that cause disease in vertebrates and in some invertebrates such as oysters. Some of the human forms are herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can later reactivate, replicate again, and infect others.In electron micrographs of HSV infection, it can be seen that the intact virus initially reacts with cell-surface proteoglycans, then with specific receptors. This is later followed by viral capsids docking with nuclear pores. Afterward, the capsids go from being full to being "empty." Which of the following best fits these observations?

The viral envelope mediates entry into the cell, the capsid mediates entry into the nuclear membrane, and the genome is all that enters the nucleus.

Viruses use the host's machinery to make copies of themselves. However, some human viruses require a type of replication that humans do not normally have. For example, humans normally do not have the ability to convert RNA into DNA. How can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires?

The viral genome codes for specialized enzymes not in the host

Viruses use the host's machinery to make copies of themselves. However, some human viruses require a type of replication that humans do not normally have. For example, humans normally do not have the ability to convert RNA into DNA. How can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires?

The viral genome has genes coding for enzymes needed for its own reproduction.

Using the life table, how would you describe the population dynamics of L. vivipara?

The population is increasing.

What unique characteristic do all deuterostomes have in common?

The pore (blastopore) formed during gastrulation becomes the anus.

If a prairie dog had the opportunity to perform an altruistic act (that is, give an alarm call) to help its relatives, which combination of the following relatives would the prairie dog be most likely to help (base your answer solely on the genetic relationships)?

The prairie dog would be equally likely to act altruistically to each of the combinations described.

Researchers found E. coli that had mutation rates 100 times higher than normal. Which of the following is the most likely cause of these results?

The proofreading mechanism of DNA polymerase was not working properly.

The genes needed for β-carotene synthesis are not normally expressed in endosperm. In the creation of golden rice, how did researchers ensure that these genes were expressed in rice endosperm?

The protein-coding sequence of each gene was linked to a regulatory region of DNA that directed transcription in endosperm.

What conclusion can you draw from the accompanying figure?

The relationship between the populations cannot be determined only from this graph.

In this experiment, Balanus was removed from the habitat shown on the left. Which of the following statements is a valid conclusion of this experiment?

The removal of Balanus shows that the realized niche of Chthamalus is smaller than its fundamental niche.

How are RNA hairpin turns related to transcriptional termination in E. coli?

The turns are formed from complementary base pairing and cause separation of the RNA transcript and RNA polymerase.

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if TRUE, would be cause for this reclassification?

The two forms interbreed often in nature, and their offspring have good survival and reproduction.

The work of Gregor Mendel provided an answer to two prevailing hypotheses popular at the time. What were these two hypotheses?

The two major hypotheses of the time were blending inheritance and inheritance of acquired characteristics.

What would the result be if a drug that blocks the action of RNA polymerase was introduced into a virus-infected organism?

The viral proteins would not be made and the virus would not be able to reproduce.

Members of two different species possess a similar-looking structure that they use in a similar way to perform about the same function. Which of the following would suggest that the relationship more likely represents homology instead of convergent evolution?

The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical

From the accompanying figure, what can we determine about the location of the food source?

The waggle dance in the bottom figure indicates that the food is 90 degrees to the right of the Sun.

Analysis of the data obtained shows that two students each have two fragments, two students each have three fragments, and two students each have one only. What does this demonstrate?

The two students who have two fragments have one restriction site in this region

In the figure, when new viruses are being assembled at the point marked IV, what mediates the assembly?

The viral components interact spontaneously and self assemble.

In electron micrographs of HSV infection, it can be seen that the intact virus initially reacts with cell-surface proteoglycans, then with specific receptors. This is later followed by viral capsids docking with nuclear pores. Afterward, the capsids go from being full to being "empty." Which of the following best fits these observations?

The viral envelope mediates entry into the cell, the capsid mediates entry into the nuclear membrane, and the genome is all that enters the nucleus.

The fruit of the mistletoe, a parasitic angiosperm, is a one-seeded berry. In members of the genus Viscum, the outside of the seed is viscous (sticky), which permits the seed to adhere to surfaces such as the branches of host plants or the beaks of birds. What should be expected of the fruit if the viscosity of Viscum seeds is primarily an adaptation for dispersal rather than an adaptation for infecting host plant tissues? It should _________.

be nutritious to the dispersing organisms

Ribosomes can attach to prokaryotic messenger RNA ________.

before transcription is complete

Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. These rituals involve fighting other males and making stylized movements that attract females. What type of reproductive isolation does this represent?

behavioral isolation

Consider the following points: (a) All excavates live in environments where oxygen availability is low; (b) all excavates lack mitochondria; and (c) all excavates have some mitochondrial genes. Based on this information, which of the following statements is TRUE of the excavate lineage?

Their ancestors had mitochondria, but the mitochondria were lost over time.

It is believed that the coelacanths and lungfish represent a crucial link between other fishes and tetrapods. What is the major feature in these fish in support of this hypothesis?

Their fins have skeletal and muscular structures similar to amphibian limbs.

Use the following description to answer the question(s) below. On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. Which type of reproductive isolation operates to keep the mosquitofish isolated, even when fish from different ponds are reunited in the same body of water?

behavioral isolation

If a fern gametophyte has both male and female gametangia on the same plant, then it ________.

belongs to a species that is homosporous

Conservationists will take snow geese off the endangered species list when the population hits 10,000. If populations are sustaining growth at r = 0.088 and the population in 2001 is 3000 individuals, in what year will snow geese be taken off the endangered species list?

between 2012 and 2015

It is estimated that a flock of wood buffalo crane should be able to sustain an r of 0.085 for the foreseeable future. If the flock currently contains 350 individuals, how long will it take for that population to double?

between 7.0 and 9.0 years

During Drosophila development, there is a regulatory cascade of gene activation. The proper sequence for this cascade is ________.

bicoid, gap genes, pair-rule genes, and segment-polarity genes

Which of the following is a characteristic of larval echinoderms?

bilateral symmetry

David Pribnow studied the base sequences of promoters in bacteria and bacterial viruses. He found two conserved regions in these promoters (the −10 box and the −35 box). These two regions of the promoter ________.

bind the sigma subunit that is associated with RNA polymerase

In eukaryotes, general transcription factors ________ .

bind to other proteins or to the TATA box

Which of the following processes is central to the initiation of transcription in bacteria?

binding of sigma to the promoter region

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the ________.

binding of the anticodon to the codon and the attachment of amino acids to tRNAs

The best type of scientist to organize a large amount of genome sequence data would be someone who specializes in ________.

bioinformatics

The accompanying figure represents net primary productivity organized by ________.

biome

As hominins diverged from other primates, which of the following appeared first?

bipedal locomotion

In what respect do hominins differ from all other anthropoids?

bipedal posture

Due to its system of air sacs connected to the lungs, the respiratory system of birds is arguably the most effective respiratory system of all air-breathers. Upon inhalation, air first flows into posterior air sacs, then into the lungs, and then into anterior air sacs on the way to being exhaled. Thus, there is one-way flow of air through the lungs, along thousands of tubules called parabronchi. Which type of bird is most likely to benefit from air sacs, which reduce its weight?

birds, such as geese, which migrate great distances

Which one of these mollusk groups can be classified as suspension feeders?

bivalves

Which of the following groups is characterized by unusual flagella contained within a structure called the outer sheath?

Spirochaetes/Spirochetes

What information is critical to the success of polymerase chain reaction (PCR) itself?

The DNA sequence of the ends of the DNA to be amplified must be known.

The first class of drugs developed to treat AIDS, such as AZT, were known as reverse transcriptase inhibitors. They worked because they ________.

bonded to the viral reverse transcriptase enzyme, thus preventing the virus from making a DNA copy of its RNA genome

Which of the following biomes has the highest variation in annual temperature?

boreal forests/taiga

Which of the following traits do archaeans and bacteria share?

both B and C

Looking at the results in the accompanying figure, which hypothesis (by Clements or Gleason) is supported by the data? I. Clements II. Gleason

both I and II

About thirteen different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the thirteen species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza). If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

Their genomes should be more similar to each other than are the genomes of the five tree finch species.

The herbicide 2,4-D affects the metabolism of dicots and kills most of them. What is a common feature of plants that are susceptible to 2,4-D?

branching leaf veins

An early step in shotgun sequencing is to ________.

break genomic DNA at random sites

Orchid bees are to Brazil nut trees as ________ are to pine trees.

breezes

You find a wormlike animal while scuba diving and want to determine whether it is a nudibranch, a polychaete, or a flatworm. Finding which of the following traits would best help you classify the mystery animal?

bristle-like structures on tiny appendages

Biologists now routinely test for homology between genes in different species. If genes are determined to be homologous, it means that they are related ________

by descent from a common ancestor

Apart from direct amphibian-to-amphibian contact, what is the most likely means by which the zoospores spread from one free-living amphibian to another?

by flagella

Alternative RNA splicing ________.

can allow the production of proteins of different sizes and functions from a single mRNA

Transgenic mice are useful to human researchers because they ________.

can be valuable animal models of human disease

Natural selection ________.

can favor beneficial mutations

Imagine that you have set up a genetic screen to identify E. coli mutants that cannot metabolize the amino acid tryptophan for energy. Beginning with a master plate containing many colonies, you prepare replica plates on medium with glucose or tryptophan as the only energy source. You would look for colonies that ________.

can grow only on the plates with glucose

Which of the following is an example of homoplasy?

cell walls in plants and fungi

When a mosquito infected with Plasmodium first bites a human, the Plasmodium ________.

cells infect the human liver cells

You are interested in studying a receptor and decide to make a knockout mouse. However, you notice severe developmental defects that result in embryonic lethality in this receptor knockout. Which developmental process is most likely affected when you disrupt a receptor on the cell surface, disrupting its ability to receive a signal and initiate a transduction pathway?

cell—cell interactions

Nudibranchs, a type of predatory sea slug, can have various protuberances (that is, extensions) on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear many chemoreceptors. Dorsal plummules, usually located posteriorly, perform respiratory gas exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips. The stingers of honeybees have a function most similar to that of ________.

cerata

Random spacing patterns in plants such as the creosote bush are most often associated with ________.

chance

The larvae of some insects are merely small versions of the adult, whereas the larvae of other insects look completely different from adults, eat different foods, and may live in different habitats. Which of the following is most directly involved in the evolution of these variations in metamorphosis?

changes in the homeobox genes governing early development

According to our current knowledge of plant evolution, which group of organisms should feature cell division most similar to that of land plants?

charophytes

A shared derived characteristic for members of the arthropod subgroup that includes spiders would be the presence of ________.

chelicerae

A compound known as X-gal is widely used in molecular genetic research. When wild-type (normal) E. coli is grown on medium containing X-gal, the bacterial colonies turn blue. In contrast, when lacZ mutants are grown on medium containing X-gal, the bacterial colonies remain their normal white color. X-gal is likely to be a compound ________.

chemically similar to lactose

Which of the following obtain energy by oxidizing inorganic substances to obtain energy that is used, in part, to fix carbon dioxide?

chemoautotrophs

A newly discovered organism is found to use sulfide (S2−) for aerobic respiration and carbon dioxide (CO2) from the air as a source of carbon, much like a plant. This organism must be a ________.

chemolithoautotroph

Which mollusk group can be described as having several calcium carbonate plates along their dorsal side?

chitons

Which of the following was derived from an ancestral cyanobacterium?

chloroplast

Which of the following would you classify as something other than an animal?

choanoflagellates

To apply parsimony to constructing a phylogenetic tree, ________.

choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology

You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile, using many short extensions of the cytoplasm. It has well-developed organelles and two nuclei, one large and one small. This organism is most likely to be a ________.

ciliate

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

cleavage → gastrulation → organogenesis

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

cleavage →gastrulation →organogenesis

Which of the following most correctly describes the whole-genome shotgun technique for sequencing a genome?

cloning fragments from many copies of an entire chromosome, sequencing the fragments, and then ordering the sequences

Which group of seedless vascular plants was the first to evolve roots?

club mosses

Many songbirds breed in North America in the spring and summer and then migrate to Central and South America in the fall. They spend the winter in these warmer areas, where they feed and prepare for the spring migration north and another breeding season. Two hypothetical species of sparrow, A and B, overwinter together in mixed flocks in Costa Rica. In spring, species A goes to the east coast of North America, and species B goes to the west coast. What can you say about the isolating mechanisms of these two species?

Their winter habitat has no bearing on their degree of reproductive isolation.

What is the primary limiting factor that determines why no female animal can produce a very large number of very large eggs?

There are energy constraints.

Which of the following statements is correct?

There are fossils of animals in geological strata that are older than the Cambrian.

Recent studies have shown that xeroderma pigmentosum (an error in the nucleotide excision repair process) can result from mutations in one of seven genes. What can you infer from this finding?

There are several proteins involved in the nucleotide excision repair process.

Which of the following statements is consistent with the assertion that protists are paraphyletic?

There is no common set of synapomorphies that define a protist

Why would you expect some white-fronted bee-eaters to fly very far away from their nests to forage when there are food sources nearby? Base your answer on your knowledge of cost— benefit analyses,

There might be some plentiful food sources further away.

Unequal crossing over during prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, so-called hemoglobin Lepore, exists in the human population. Hemoglobin Lepore has a deleted series of amino acids. If this mutated form was caused by unequal crossing over, what would be an expected consequence?

There should also be persons whose hemoglobin contains two copies of the series of amino acids that is deleted in hemoglobin Lepore.

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, what would happen in environments that lack antibiotics?

These bacteria would be outcompeted and replaced by bacteria that have lost these genes.

Why is it important that ectomycorrhizal fungi (EMF) have peptidase enzymes?

These enzymes are needed to release nitrogen from dead plant material in colder environments.

Which of the following is TRUE of species interactions?

They can act as agents of natural selection.

Most moss gametophytes do not have a cuticle and are 1—2 cells thick. What does this imply about moss gametophytes and their structure?

They can easily lose water to, and absorb water from, the atmosphere

If the sequence of a cDNA has matches with DNA sequences in the genome, then this genomic DNA is likely to ________.

code for a protein

Gap genes, segment-polarity genes, and homeotic genes all ________.

code for transcription regulatory factors

Liverworts, hornworts, and mosses are grouped together as Bryophytes. Besides not having vascular tissue, what do they all have in common?

They require water for reproduction.

Trichoplax adhaerens (Tp) is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. They move using cilia, and any "edge" can lead. Tp feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. Tp sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage. Which of the following Tp traits is different from those of most other animals?

Tp lacks muscle and nerve cells.

Epiphytic orchids grow harmlessly on their host trees, and derive their resources from the air and from rain, rather than from their host plant. Which of the following is the best description of this species interaction?

commensalism

Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small vertebrates that fly or jump out of the way of the ants. This situation is an example of what kind of species interaction between the birds and the ants?

commensalism

Any process in which a signal from one individual modifies the behavior of a recipient individual is termed ________.

communication

Connell conducted this experiment to learn more about ________.

competitive exclusion and distribution of barnacle species

The anticodon of a particular tRNA molecule is ________.

complementary to the corresponding mRNA codon

Which of the following occurs in prokaryotes but not in eukaryotes?

concurrent transcription and translation

Given that phylogenies are based on shared derived characteristics, which of the following traits is useful in generating a phylogeny of species W, X, Y, and Z?

Trait 2

Which of the following is one of the technical reasons why gene therapy is problematic?

Transferred genes may not have appropriately controlled activity

Which species interaction depends on prey density and effectiveness of prey defenses to determine the impact on the prey population?

consumption

All protists ________.

contain a nucleus

Imagine that you compare two DNA sequences found in the same location on homologous chromosomes. On one of the homologs, the sequence is AACTACGA. On the other homolog, the sequence is AACTTCGA. Within a population, you discover that each of these sequences is common. These sequences ________.

contain an SNP that may be useful for genetic mapping

What was an early selective advantage of a coelom in animals? A coelom ________.

contributed to a hydrostatic skeleton, allowing greater range of motion

Which method is utilized by eukaryotes to control their gene expression that is NOT used in bacteria?

control of both RNA splicing and chromatin remodeling

Some beetles and flies have antler-like structures on their heads, much like male deer do. The existence of antlers in beetle, fly, and deer species with strong male—male competition is an example of ________.

convergent evolution

The evolution of similar insulating skin coverings such as fur, hair, and feathers in mammals and birds is a result of ________.

convergent evolution

HIV is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. What are the practical consequences of these findings?

The flu virus can be transmitted more easily from person to person than HIV.

If in the future the current molecular evidence regarding animal origins is further substantiated, what will be TRUE of any contrary evidence regarding the origin of animals derived from the fossil record?

The fossil evidence will be understood to have been interpreted incorrectly because it is incomplete.

Detritivores ________.

convert organic materials from all trophic levels to inorganic compounds usable by primary producers

A prokaryote that obtains carbon and energy by ingesting prey is a(n) ________.

heterotroph and chemotroph

A prokaryote that obtains energy and carbon as it decomposes dead organisms is a(n) ________.

heterotroph and chemotroph

All fungi are ________.

heterotrophic

The question(s) below refer to the following paragraph. A sediment core is removed from the floor of an inland sea. The sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. Researchers wish to locate and study the terrestrial organisms fossilized in this core. The core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonized by life. If arrows indicate locations in the column where fossils of a particular type (see key in the accompanying figure) first appear, then which core in the figure has the most accurate arrangement of fossils?

core A

Which of the following examples would most accurately measure the density of the population being studied?

counting the number of moss plants in 1-square-meter quadrants

The possession of two pairs of antennae is a characteristic of ________.

crustaceans

In the figure, which of the following survivorship curves most applies to humans living in developed countries?

curve A

In the accompanying figure, which of the following survivorship curves implies that an animal may lay many eggs with the same probability of dying each year of life?

curve B

Plantlike photosynthesis that releases oxygen (O2) occurs in ________.

cyanobacteria

Lichens are symbiotic associations of fungi and ________.

cyanobacteria or algae

Cystic fibrosis is a genetic disorder in homozygous recessive (ff) humans that typically significantly reduces life expectancy. Over time, we would expect the f allele frequency to ________ for this trait.

decrease

What factor could potentially increase the length of a food chain?

decrease in the amount of energy in a trophic level that is lost as it passes to the next higher level

Currently, the only predators of Galápagos marine iguanas are Galápagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators (for example, cats) that preferentially catch and eat slower iguanas are introduced to the island, iguana body size is likely to ________ in the absence of other factors; the iguanas would then be under ________ selection.

decrease; directional

The recessive allele that causes sickle cell anemia is harmful to homozygous individuals. What maintains the presence of this allele in a population's gene pool?

heterozygote advantage

The greatest expression of the lac operon occurs when lactose levels are ________.

high and glucose levels are low

Natural selection involves energetic trade-offs between ________.

high survival rates of offspring and the cost of parental care

In a nucleosome, the DNA is wrapped around ________.

histones

Mutations in which of the following genes lead to transformations in the identity of entire body parts?

homeotic genes

Suppose you found several Drosophila mutants that possessed additional legs growing out of their head segments. The probable mutation would be found in ________.

homeotic genes

Which of the following choices would most likely promote random distribution?

homogeneous chemical and physical factors in the environment

A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. In one set of experiments she succeeded in increasing acetlylation of histone tails. Which of the following results would she most likely see?

decreased chromatin condensation

Which of the following is the most predictable outcome of increased gene flow between two populations?

decreased genetic difference between the two populations

If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced the sunlight reaching Earth's surface by 70 percent for 1 year, which of the following marine communities most likely would be LEAST affected?

deep-sea vent

The major function of medicinal compounds in plants is to ________.

defend the plant against herbivores

Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently, assuming that nothing is done to counter the reduction of intestinal bacteria, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become ________

deficient in certain vitamins and nutrients

In combination, the products of gap genes, pair-rule genes, and segmentation-polarity genes ________.

define the segmented body plan of the embryo

Both ancestral birds and ancestral mammals shared a common ancestor that was a terrestrial vertebrate. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?

homology; homoplasy

The common ancestors of birds and mammals were very early (stem) amniotes, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as ________.

homoplasies

If, someday, an Archaean cell is discovered with an rRNA sequence that is more similar to that of humans than the sequence of mouse rRNA is to that of humans, the best explanation for this apparent discrepancy would be ________.

homoplasy

Mimivirus contains some of the genes required for protein synthesis. This is cited as support for which hypothesis about the origins of viruses?

degeneration

The study of factors that determine the size and structure of populations through time is called ________.

demography

An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square kilometer in one woodlot and 20 per square kilometer in another woodlot. What was the ecologist comparing?

density

The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?

different possible assortment of chromosomes into gametes

The two populations are ________.

different subspecies, under the morphological species concept

Several of the different globin genes are expressed in humans but at different times in development. What mechanism could allow for this?

differential gene regulation over time

You might be interested to know how many different types of bacteria live on the shower curtain in your bathroom. What is the most efficient method for finding out?

direct sequencing

In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?

directional selection

One example of an innovation from an unexpected source comes from studies of tumor-like plant growths. What information did the study of plant tumors provide that was critical for plant genetic engineering?

discovery of a plasmid that could be modified to introduce genes into plants

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it ________.

dismissed the idea that species are constant and emphasized the importance of variation and change in populations

Three-spined stickleback fish (Gasterosteus aculeatus) show substantial heritable variation in gill-raker length related to differences in their diets. Longer gill rakers appear to function better for capturing open-water prey, while shorter gill rakers function better for capturing shallow-water prey. Which of the following types of selection is most likely to be found in a large lake (open water in the middle and shallow water around the sides) with a high density of these fish?

disruptive selection

Which of the following is most likely to produce an African butterfly species in the wild whose populations show two strikingly different color patterns?

disruptive selection

A researcher notices that in a certain moth species, some females prefer to feed and lay eggs on domesticated solanaceous plants like potatoes and tomatoes. Other females prefer to feed and lay eggs on wild solanaceous plants like Datura. Both male and female moths primarily use scent to find these plants from afar. Females tend to mate where they feed, and the researcher finds a genetic basis for scent preference in these moths. Based on the above information, what might be occurring in this moth species?

divergence in sympatry

Which of the following, if discovered, could refute our current understanding of the pattern of evolution?

diverse fossils of mammals in Precambrian rock

Which of the following likely has the most Hox genes?

dolphins

The vertebrate spinal cord develops from the embryonic ________.

dorsal hollow nerve cord

The spiracles and tracheae of insects have a function most similar to that of ________.

dorsal plummules

Which of the following is a characteristic of all angiosperms?

double internal fertilization

In nature, the major mechanism of introducing new genes into eukaryotic genomes is ________.

duplication followed by evolutionary divergence

Which of the following should have had gene sequences most similar to the charophyte (stonewort) that was the common ancestor of land plants?

early bryophytes

Which of the following could be a density-independent factor limiting human population growth?

earthquakes

Which level of ecological study focuses the most on abiotic factors?

ecosystem ecology

Which of the following levels of ecological organization is arranged in the correct sequence from most to least inclusive?

ecosystem, community, population, organism

Which of the following are maternal effect genes that control the orientation of the egg and thus the Drosophila embryo?

egg-polarity genes

A frameshift mutation could result from ________.

either an insertion or a deletion of a base

Which of the following features is most important for true mosses and ferns to reproduce in the desert?

either that their gametophytes grow close together, or that they be hermaphroditic

Their next two steps, in order, should be ________

electrophoresis of the fragments, followed by the use of a probe

Meristematic tissue cells in plants are most similar to which kind of cells in animals?

embryonic stem cells

Tumor-suppressor genes ________.

encode proteins that help prevent uncontrolled cell growth

The digestive system of most animals is lined with cells through which nutrients are absorbed. What is the embryonic origin of these cells?

endoderm

Which of the following terms refers to symbiotic relationships involving fungi living between the cells in plant leaves?

endophytes

Mammals and birds eat more often than reptiles. Which of the following traits shared by mammals and birds best explains this habit?

endothermy

Which of the following characteristics evolved independently in mammals and birds?

endothermy

An organic solvent widely used in industrial processes, 1,1,1-trichloroethane (TCA), is a major environmental pollutant affecting human health and damaging the ozone layer. Recently, researchers isolated the first bacteria able to degrade TCA. They found that the bacteria use hydrogen as an electron donor, TCA as an electron acceptor, and acetate as a carbon source. Based on the preceding information, deduce the method used to isolate these bacteria.

enrichment culture

You need to identify the major type of bacteria living on the shower curtain in your bathroom and find out what they use as a food source. What is the most efficient method for answering this question?

enrichment culture

Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?

environmental factors such as soil pH

The B-I mutation in anthocyanin (red pigments) produces pigmented corn plants, whereas the B′ mutation in the same gene usually produces nearly unpigmented corn plants when homozygous (B´/B´). When homozygous B-I and B′ plants are intercrossed, the F1 plants are essentially unpigmented, like the B′ homozygotes. If this outcome were due simply to the dominance of B′ to B-I, then a self-cross of the F1 plants (B´/B-I) should generate B-I-colored homozygotes as approximately 1/4 (B-I/B-I) of the F2 progeny. Instead, no F2 are pigmented. Intercrosses of the F2 and of further generations do not restore the pigmented phenotype. What is the term for this type of inheritance?

epigenetic inheritance

DNA methylation and histone acetylation are examples of ________.

epigenetic phenomena

All protists are ________.

eukaryotic

Gene expression can be altered more easily at the level of post-transcriptional processing in eukaryotes than in prokaryotes because ________.

eukaryotic exons may be spliced in alternative patterns

If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to ________.

eventually become competitively superior to the other species

The proximate causes of behavior are interactions with the environment, but behavior is ultimately shaped by ________.

evolution

After the drought of 1977, researchers on the island of Daphne Major hypothesized that medium ground finches that had large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. If this hypothesis is correct, what would you expect to observe if a population of these medium ground finches colonizes a nearby island where T. cistoides is the most abundant food for the next 1000 years? Assume that (1) even the survivors of the 1977 drought sometimes had difficulty cracking the tough T. cistoides fruits and would eat other seeds when offered a choice; and (2) food availability is the primary limit on finch fitness on this new island.

evolution of yet larger, deeper beaks over time

Muscle cells differ from nerve cells mainly because they ________.

express different genes

Bioinformatics can be used to scan for short sequences that specify known mRNAs, called ________.

expressed sequence tags

The predominant mechanism driving cellular differentiation is the difference in gene ________.

expression

Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during the teenage years. If 9 in 10,000 newborn babies have the disease, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the Hardy—Weinberg model?

f(A1) = 0.9700, f(A2) = 0.0300

Which of the following terms do ecologists use to describe the community interaction where one organism makes the environment more suitable for another organism?

facilitation

What is the single unique characteristic that distinguishes extant birds from other extant vertebrates?

feathers

When some bacteria use lactose as a source of energy, they produce propionic acid and carbon dioxide. What is the name for this process?

fermentation

Which of the following is a land plant that has flagellated sperm and a sporophyte-dominated life cycle?

fern

In terms of alternation of generations, the internal parts of the pollen grains of seedproducing plants are most similar to a ________.

fern gametophyte bearing only antheridia

A botanist discovers a new species of plant in a tropical rain forest. After observing its anatomy and life cycle, he notes the following characteristics: flagellated sperm, xylem with tracheids, separate gametophyte and sporophyte generations with the sporophyte dominant, and no seeds. This plant is probably most closely related to ________.

ferns

Which plant group is notable for the independence of gametophyte and sporophyte generations from each other?

ferns

If humans had been present to build log structures during the Carboniferous period (though they were not!), which plant types would have been suitable sources of logs?

ferns, horsetails, and lycophytes

Six students have taken samples of their own cheek cells, purified the DNA, and used an enzyme (endonuclease) known to cut at zero, one, or two sites in a particular gene of interest. They might be conducting such an experiment to ________

find which of the students has which alleles

The last common ancestor of all animals was probably a ________.

flagellated protist

Big Bend National Park in Texas is mostly Chihuahuan desert, where rainfall averages about 24 cm per year. Yet, it is not uncommon when hiking in this bone-dry desert to encounter mosses and ferns. One such plant is called "flower of stone." It is not a flowering plant, nor does it produce seeds. Under arid conditions, its leaf-like structures curl up. However, when it rains, it unfurls its leaves, which form a bright green rosette on the desert floor. Consequently, it is sometimes called the "resurrection plant." At first glance, it could be a fern, a true moss, or a spike moss. What feature of both true mosses and ferns makes it most surprising that they can survive for many generations in dry deserts?

flagellated sperm

Which of the following characteristics is unique to chytrids compared to other groups of fungi?

flagellated spores

Chronic myelogenous leukemia (CML) results from a translocation between human chromosomes 9 and 22. The resulting chromosome 22 is significantly shorter than usual, and it is known as a Philadelphia (Ph') chromosome. The junction at the site of the translocation causes overexpression of a receptor tyrosine kinase. A new drug (Gleevec or imatinib) has been found to inhibit the disease if the patient is treated early. Which of the following would be a reasonably efficient technique for confirming the diagnosis of CML?

fluorescent labeling to determine the chromosomal location of all chromosome 22 fragments

A cephalopod's tentacles are modified from its ________.

foot

A snail-like, coiled, porous test (shell) of calcium carbonate is characteristic of ________.

foraminiferans

Amoeboid movement via long slender pseudopodia is characteristic of ________.

foraminiferans

The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid1700s. They do not marry with members outside their own immediate community. Today, the Dunkers are genetically unique and differ in gene frequencies, at many loci, from all other populations, including those in their original homeland. Which of the following likely explains the genetic uniqueness of this population?

founder effect, inbreeding, and genetic drift

Soon after the island of Hawaii rose above the sea surface (somewhat less than 1 million years ago) and organisms colonized the island, the evolution of life on this new island should have been most strongly influenced by ________.

founder effects

When imbalances occur in the sex ratio of sexual species that have two sexes (that is, other than a 50:50 ratio), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. This is most clearly an example of ________.

frequency-dependent selection

According to the endosymbiosis theory of the origin of eukaryotic cells, how did mitochondria originate?

from engulfed, originally free-living proteobacteria

The purple nonsulfur bacterium Rhodospirillum grows best as a photoheterotroph. What are the most favorable sources of energy and carbon for this bacterium?

fructose and light

Angiosperms are the most successful terrestrial plants. Which of the following features is unique to them and helps account for their success?

fruits enclosing seeds

The water vascular system of echinoderms ________.

functions in locomotion and feeding

When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter?

fungal enzymes

When pathogenic fungi are found growing on the roots of grape vines, grape farmers sometimes respond by covering the ground around their vines with plastic sheeting and pumping a gaseous fungicide into the soil. The most important concern of grape farmers who engage in this practice should be that the ________.

fungicide might also kill mycorrhizae

Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. Pollen grains (which contain sperm nuclei) from one species are unable to germinate and make pollen tubes to bring the sperm nuclei to the female ovules (which contain egg cells) of the other species. These two juniper species are kept separate by ________.

gametic isolation

As you stroll through a moist forest, you are most likely to see a ________.

gametophyte of a moss

Alternation of generations occurs in some protists. Which of the following represents the correct sequence of events for this mode of reproduction?

gametophyte → gamete → fusion → sporophyte → spore → gametophyte

Which of the following is a fitness trade-off (compromise)?

Turtle shells provide protection but are heavy and burdensome when moving.

Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?

gaps left at the 5' end of the lagging strand

A terrestrial mollusk without a shell belongs to which clade?

gastropods

Which mollusk clade includes members that undergo embryonic torsion?

gastropods

At which developmental stage should one be able to first distinguish a diploblastic embryo from a triploblastic embryo?

gastrulation

Cells move to new positions as an embryo establishes its three germ-tissue layers during ________.

gastrulation

Plant embryos do NOT undergo the process of ________.

gastrulation

What does the biological species concept use as the primary criterion for determining species boundaries?

gene flow

Which of the following does NOT tend to promote speciation?

gene flow

In hybrid zones where reinforcement is occurring, you should see a decline in ________.

gene flow between distinct gene pools

The presence of altruistic behavior is most likely due to kin selection, a theory maintaining that ________.

genes enhance survival of copies of themselves by directing organisms to assist others who share those genes

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

genes involved in control of the cell cycle

Although the expression of most genes is tightly regulated, some genes are expressed at roughly constant rates. Which of the following genes would you predict to be constitutively (constantly) expressed?

genes that code for regulatory proteins

A multigene family is composed of ________.

genes whose sequences are very similar and that probably arose by duplication

Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains?

genetic characteristics such as ribosomal RNA sequences

Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception

genetic drift

Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence?

genetic drift

Which of the following describes the most likely order of events in allopatric speciation?

genetic isolation, genetic drift, divergence

Which of the following characteristics, structures, or processes is common to bacteria and viruses?

genetic material composed of nucleic acid

Which of the following characteristics, structures, or processes is common to bacteria and viruses?

genetic material composed of nucleic acids

If the isthmus formed gradually rather than suddenly, what pattern of genetic divergence would you expect to find in these species pairs?

greater percentage of difference in DNA sequence between species that inhabit deep water than between species that inhabit shallow water

The most direct ancestors of land plants were probably ________.

green algae

Feather color in budgies is determined by two different genes, Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. A blue budgie is crossed with a white budgie. Which of the following results is NOT possible?

green and yellow offspring

Nematodes and arthropods both ________.

grow by shedding their exoskeleton

Where are you LEAST likely to see green algae?

growing independently on dry rock in meadows

During exponential growth, a population always ________

grows at its maximum per capita rate

Which of the following showed their greatest diversity during the Mesozoic era but were a small, less diverse group during the Paleozoic era?

gymnosperms

In the accompanying figure, at the arrow marked II, what enzyme(s) are being utilized?

host cell DNA polymerase

RNA viruses require their own supply of certain enzymes because ________.

host cells lack enzymes that can replicate the viral genome

In E. coli, if RNA polymerase is missing ________, then transcription initiation would not occur at the appropriate initiation sites.

sigma

A lizard's bobbing dewlap (a colorful flap of skin hanging from an Anolis lizard's throat) is an example of a(n) ________.

signal

You find a small animal with eight legs crawling up your bedroom wall. Closer examination will probably reveal that this animal also has ________.

simple, but not compound, eyes

Which of the following help(s) to hold the DNA strands apart while they are being replicated?

single-strand DNA binding proteins

Use the following description to answer the question(s) below. On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. The very closely related species Drosophila santomea is found at higher elevations and only on Sao Tomé. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, where hybrids are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago. Which of the following reduces gene flow between the gene pools of the two species on Sao Tomé, despite the existence of hybrids?

hybrid sterility

Reinforcement is most likely to occur when ________.

hybrids have lower fitness than either parent population

What type of bonding is responsible for maintaining the shape of the tRNA molecule shown in the figure above?

hydrogen bonding between base pairs

Long, branching fungal filaments are called ________.

hyphae

After finding a new medicinal plant, a pharmaceutical company decides to determine if the plant has genes similar to those of other known medicinal plants. To do this, the company annotates the genome of the new plant to ________

identify genes and determine their functions

The "universal" genetic code is now known to have exceptions. Evidence for this can be found if which of the following is TRUE?

if UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only) in a different organism

The areas that have received the greatest attention in genetically modified plants are ________.

improved product quality and increased pest and herbicide resistance

According to the fossil record, plants colonized terrestrial habitats ________.

in conjunction with fungi that helped provide them with nutrients from the soil

A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. One of her colleagues suggested she try increased methylation of C nucleotides in the DNA of promoters of a mammalian system. Which of the following results would she most likely see?

inactivation of the selected genes

Which of the following would be LEAST likely to cause DNA damage to an individual suffering from xeroderma pigmentosum (XP)?

incandescent lightbulbs

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following?

incomplete dominance

In comparing DNA replication with RNA transcription in the same eukaryotic cell, only DNA replication ________.

incorporates the entire template molecule in the product

Wikelski and Romero (2003) found that large marine iguanas had higher reproductive success than smaller iguanas did. However, the large iguanas were generally in poor body condition because they could not eat enough; at higher temperatures, their foraging efficiency improved, allowing them to eat more. Thus, Wikelski and Romero hypothesized that iguana size will ________ as global warming gradually increases air and water temperatures in the Galápagos Islands.

increase

In the first step of their experiments, Jacob and Monod treated E. coli cells with ultraviolet light or X-rays to ________.

increase the frequency of mutations in all genes

Which of the following human activities is impacting the water cycle the LEAST?

increased processing of salt water to freshwater

After the drought of 1977, researchers hypothesized that on the Galápagos island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough T. cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of these events is now most likely to occur to finch beaks on this island?

increased variation in beak size and shape over time

Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation?

inducer

Which of the following, when taken up by a cell, binds to a repressor so that the repressor no longer binds to the operator?

inducer

Consider the global nitrogen cycle depicted in the accompanying figure. How are humans altering this cycle?

industrial nitrogen fixation

Regarding these sequence homology data, the principle of maximum parsimony would be applicable in ________.

inferring evolutionary relatedness from the number of sequence differences

Regulatory transcription factors ________.

influence the assembly of the basal transcription complex

Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their nutrition by ________

ingesting prey

In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a single species dominated the field. A possible factor in this secondary succession was ________.

inhibition

The product of the p53 gene ________.

inhibits the cell cycle

Which is a likely biotic factor limiting songbird distribution in Hawaii to alpine habitats?

insects causing fatal diseases in songbirds at lower altitudes

How do we describe transformation in bacteria?

insertion of external DNA into a cell

Effective antiviral drugs are usually associated with which of the following properties?

interference with viral replication

A nonsense mutation in a gene ________.

introduces a premature stop codon into the mRNA

A certain species of pine tree survives only in scattered locations at elevations above 2800 meters in the western United States. To understand why this tree grows only in these specific places, an ecologist should ________.

investigate the various biotic and abiotic factors that are unique to high altitude

A mutation that results in premature termination of translation ________.

is a nonsense mutation

The presence of a lophophore in a newly discovered species would suggest that the species ________.

is a suspension feeder

An organism that exhibits cephalization probably also ________.

is bilaterally symmetrical

The statement "DNA → RNA → Proteins" ________.

is known as the central dogma

You find a green organism in a pond near your house and believe it is a plant, not an alga. The mystery organism is most likely a plant and not an alga if it ________.

is surrounded by a cuticle

Which one of the following is TRUE? A codon ________.

is the basic unit of the genetic code

Mutation is the only evolutionary mechanism that ________.

is the ultimate source of variation in natural populations

To establish a link between a specific bacterium and a skin disease, researchers have shown that the bacterium was present in sick persons but not in healthy individuals. They isolated the bacterium in a pure culture and demonstrated that experimental healthy animals injected with this culture became sick. What other experiment do researchers need to perform to be absolutely sure that the bacterium is responsible for the disease?

isolate bacterium from an infected sick animal and demonstrate that it is the same bacterium as the one used for infection

The competitive exclusion principle states that ________.

it is not possible for two species with the same niche to coexist in the same region

In a tide pool, 15 species of invertebrates were reduced to 8 after one species was removed. The species removed was likely a(n) ________.

keystone species

Gene therapy requires ________.

knowledge and availability of the normal allele of the defective gene, an ability to introduce the normal allele into the patient, and an ability to express the introduced gene at the correct level, and time, and tissue site within the patient

Terry catches a ray-finned fish from the ocean and notices that attached to its side is an equally long, snakelike organism. The attached organism has no external segmentation, no scales, a round mouth surrounded by a sucker, and two small eyes. Terry thinks it might be a marine leech, a hagfish, or a lamprey. Which feature excludes the organism from possibly being a leech?

lack of external segmentation

If you are a human geneticist looking for an ideal population in which to map disease genes, which of the following characteristics would help the mapping study?

large family sizes with well-known genealogies

Sequencing eukaryotic genomes is more difficult than sequencing genomes of bacteria or archaea because of the ________.

large size of eukaryotic genomes and the large amount of eukaryotic repetitive DNA

Following the fusion of gametes in Obelia, the resulting cell divides via mitosis to become a ________.

larva

Imagine that you have sequenced the genome of a human pathogenic bacterium. In the early stages of analysis, you discover a stretch of DNA that has a significantly different G-C content (the proportion of bases that are G and C). Further examination of this region shows there are roughly one dozen protein-coding regions. These are not found in the genome of a previously sequenced and related nonpathogenic bacterium. These sequences do, however, predict protein products strikingly similar to those of another bacterial pathogen that is not closely related to the organism you are studying. You immediately suspect ________.

lateral gene transfer

Which of the following terms defines how the individual organism allocates resources to growth, reproduction, and activities or structures related to survival?

life history

Which one of the following is LEAST likely to cause mutations in DNA?

light from an incandescent bulb

Which of the following occurs in vascular land plants but not charophytes (stoneworts)?

lignin

In the accompanying figure, which of the lines represents the highest per capita rate increase (r)?

line A

If you think of the earthworm body plan as a drinking straw within a pipe, where would you expect to find most of the tissues that developed from endoderm?

lining the straw

We know the streamlined bodies shown in the accompanying figure are examples of homoplasy. If the following groups also had streamlined bodies, which of the groupings would give the most support to this body type being homologous?

lizards, pterosaurs, dinosaurs, birds, synapsids, monotremes, marsupials, rodents, and primates

A(n) ________ has a crown of ciliated tentacles that function in feeding

lophophore

Assume that some members of an aquatic species of motile, photosynthetic protists evolve to become parasitic to fish. They gain the ability to live in the fish gut, absorbing nutrients as the fish digests food. Over time, which of the following phenotypic changes would you expect to observe in this population of protists?

loss of chloroplasts

Which group's members have both lungs and gills during their adult lives?

lungfishes

According to the central dogma, what molecule should go in the blank? DNA → ________ → Proteins

mRNA

Codons are part of the molecular structure of ________.

mRNA

Translation requires ________.

mRNA, tRNA, and rRNA

Translation directly involves ________.

mRNA, tRNA, ribosomes, and GTP

Learning has the most influence on behavior when ________.

making mistakes does not result in death

Fossils of Thrinaxodon, a species that lived during the Triassic period, have been found in both South Africa and Antarctica. Thrinaxodon had a reptile-like skeleton and laid eggs, but small depressions on the front of its skull suggest it had whiskers and, therefore, fur. Thrinaxodon may have been warm-blooded. The fossils of Thrinaxodon are consistent with the hypothesis that ________.

mammals evolved from a reptilian ancestor

If a lung were to be found in a mollusk, where would it be located?

mantle cavity

A radula is a specialized feeding organ used to scrape material off of a substrate for ingestion, much like a cheese grater scrapes shreds off of a block of cheese. Snails, which have this structure, are thus which kind of feeder?

mass feeder

In house sparrows (Passer domesticus) it is generally found that both males and females care for the eggs and young. However, some male house sparrows do not provide parental care. In addition, it is known that young that receive parental care from both the male and female are more likely to survive to fledging (leaving the nest). Which of the following activities by males that do NOT provide parental care would represent the most beneficial trade-off for the reduced survival of their offspring?

mating with additional females and fathering more eggs

Cloning of plants from cuttings demonstrates that ________.

mature plant cells retain the full genetic information needed to carry out the developmental processes to produce a new individual plant

A population's carrying capacity ________.

may change as environmental conditions change

Archegonia ________.

may contain sporophyte embryos

Which set contains the most closely related terms?

megasporangium, megaspore, egg, ovule

You want to get rid of your cough and stuffy nose, and a friend offers you a cup of tea. After you drink the tea, you realize that you are feeling relief from your symptoms. What plant compound was most likely found in the tea?

menthol

What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'

met-ser-ser-leu-ser-leu

The figure shown here represents the dynamics of ________.

metapopulations

During cellular respiration, some bacteria use methane (CH4) as an electron donor and oxygen (O2) as an electron acceptor. What is the name for this group of bacteria?

methanotrophs

Consider the following section of mRNA: UCUGAUGGGCUUU... Beginning with the start codon, which amino acids, in order, are coded for by this section of mRNA? Consult the codon table provided if necessary.

methionine, glycine, phenylalanine

The mutation resulting in sickle cell disease changes one base pair of DNA so that a codon now codes for a different amino acid, making it an example of a ________

missense mutation

The generative cell of male angiosperm gametophytes is haploid. This cell divides to produce two haploid sperm cells. What type of cell division does the generative cell undergo to produce these sperm cells?

mitosis

Which one of the following processes in a developing embryo is a prerequisite for all of the other processes?

mitosis

What kind of molecules serve as electron acceptors in cellular respiration?

molecules with low potential energy

When considering the wormlike phyla within the protostomes, which feature is most useful in distinguishing groups?

molting as they grow larger

According to the evidence collected so far, the animal kingdom is ________.

monophyletic

There are more species in tropical areas than in places more distant from the equator. This is probably a result of ________.

more intense annual solar radiation

Fossils of Lystrosaurus, a dicynodont therapsid, are most common in parts of modern-day South America, South Africa, Madagascar, India, South Australia, and Antarctica. The animal apparently lived in arid regions and was mostly herbivorous. It originated during the midPermian period, survived the Permian extinction, and dwindled by the late Triassic, though there is evidence of a relict population in Australia during the Cretaceous period. Some dicynodonts had two large tusks, extending down from their upper jaws. The tusks were not used for food gathering and in some species were limited to males. Food was gathered using an otherwise toothless beak. Judging from the fossil record in sedimentary rocks, these pig-sized organisms were the most common mammalian ancestors of the Permian. Which of the following is the most likely explanation for the modern-day distribution of dicynodont fossils? The dicynodonts were ________.

most abundantly distributed throughout Gondwana

Which of the following cells have reduced or very little active telomerase activity?

most normal somatic cells

Trichoplax adhaerens (Tp) is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. They move using cilia, and any "edge" can lead. Tp feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. Tp sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage. Tp's body symmetry seems to be most like that of ________.

most sponges

Due to its unusual habitat (inside the digestive tracts of other animals), the tapeworm lacks a ________.

mouth and a digestive tract

Primate evolution and behavior, such as hunting skills, have been directed in part by the development of depth perception. What anatomical change made depth perception possible?

movement of eyes to the front of the head

Genetic variation ________.

must be present in a population before natural selection can act upon the population

Point mutations are referred to as missense, silent, frameshift, or nonsense when they change the protein-coding potential of a gene. What is another group of mutations that may have important consequences for gene expression?

mutations that exist outside coding sequences

Phylogenetic trees constructed from evidence from molecular systematics are based on similarities in ________.

mutations to homologous genes

Some fungal species can kill herbivores while feeding off of sugars from its plant host. What type of relationship does this fungus have with its host?

mutualistic

According to Hamilton's rule, ________.

natural selection favors altruistic acts when the resulting benefit to the beneficiary, corrected for relatedness, exceeds the cost to the altruist

A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. The actual forelimbs of these mammals do NOT seem to be optimally arranged because ________.

natural selection is generally limited to modifying structures that were present in previous generations and/or in previous species

With regard to understanding the evolution of cooperation, the principal prediction that can be made from the expression Br > C is that ________.

natural selection will favor cooperation among close relatives

To make a vaccine against mumps, measles, or rabies, which type of viruses would be useful?

negative-sense ssRNA viruses

Which of the following is (are) unique to animals?

nervous system signal conduction and muscular movement

Which tissue type, or organ, is NOT correctly matched with its germ layer tissue?

nervous—mesoderm

When primary producers expend energy to build new tissue, this is ________.

net primary productivity and the amount of energy available to consumers

Histone acetyl transferases exert their effect on gene activity by ________.

neutralizing positive charges on the lysines of histones

A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. Which component of the complex described enters the exit tunnel in the large subunit of the ribosome?

newly formed polypeptide

What is the term used to describe the process shown in the panels in the accompanying figure, assuming Time 2 follows Time 1?

niche differentiation

Nitrogen is available to plants mostly in the form of ________.

nitrate and ammonium ions in the soil

Consider the global nitrogen cycle depicted in the accompanying figure. What is the limiting portion of the cycle for plants?

nitrogen fixation by bacteria

It has been hypothesized that fungi and plants have a mutualistic relationship because fungi provide critical nitrogen for the plants' use. How do we know this happens? In experiments using radioactively labeled ________.

nitrogen, plants acquired more radioactive nitrogen when they were associated with fungi

Based on graphs in the accompanying figure, which of the following is the best description of the data supporting the idea that a plant species did not form mycorrhizae with a fungus? Its biomass is greatest when ________

no AMF are present

For a biologist studying a small fish population in the lab, which Hardy—Weinberg condition is easiest to meet?

no gene flow

A new species of aquatic chordate is discovered that closely resembles an ancient form. It has the following characteristics: external armor of bony plates, no paired lateral fins, and a suspension-feeding mode of nutrition. In addition to these, it will probably have which of the following characteristics?

no jaws

For biologists studying a large flatworm population in the lab, which Hardy—Weinberg condition is most difficult to meet?

no mutation

At the beginning of this century there was a general announcement regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes. Many people were surprised that the number of protein-coding sequences was much smaller than they had expected. Which of the following could account for much of the DNA that is NOT coding for proteins?

non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function

Vestigial traits and neutral changes in DNA sequences are good examples of ________.

nonadaptive traits

Internal fertilization, a leathery amniotic egg, and skin that resists drying are characteristics of ________.

nonbird reptiles

Which of the following statements is TRUE about a phylogeny, as represented by a phylogenetic tree? I. Descendant groups (branches) from the same node do not share any derived characters. II. A monophyletic group can be properly based on convergent features. III. The ancestral group always displays all the synapomorphies of the descendant species.

none; not I, II, or III

Which of the following factors, when used to label the horizontal axis of the accompanying graph, would account most directly for the shape of the plot?

number of choanocytes per sponge

What would be the best anatomical feature to look for to distinguish a gastropod from a chiton?

number of shell plates

What is the major distinguishing characteristic of fungi?

nutrient acquisition via external digestion

A 3-hectare lake in the American Midwest suddenly has succumbed to an algal bloom. What is the likely cause of this in freshwater ecosystems?

nutrient runoff

Considering the global carbon cycle, which of the following is the largest reservoir of carbon?

oceans

In eukaryotes, the normal or default state is that genes are turned ________.

off through their association in nucleosomes

Echinoderms ________.

often use tube feet to move around in their environment

DNA replication is highly accurate. It results in about one mistake per billion nucleotides. For the human genome, how often would errors occur?

on average, six times each time the entire genome of a cell is replicated

In the nitrogen cycle, the bacteria that replenish the atmosphere with nitrogen are ________.

ones that use nitrogen-containing compounds as an electron acceptor

The regular fluctuations in size of animal populations are termed ________. I. population cycles II. population dynamics III. growth factors

only I

In the map above, where will the weather be drier? I. near 30° N II. near 30° S III. near the Equator

only I and II

The specific abiotic factors defining a biome are ________. I. annual variation in temperature and precipitation II. average annual temperature and moisture levels III. maximum annual temperature and moisture levels IV. maximum annual temperatures, moisture levels, and average annual temperature

only I and II

What is the main reason for using food webs instead of food chains in analyzing ecosystems? I. Most organisms eat more than one type of food. II. Most organisms feed at several trophic levels. III. The decomposition cycle needs to be shown.

only I and II

Which of the following is a source of human-fixed nitrogen? I. industrially produced fertilizers II. cultivation of soybeans III. irrigation agriculture

only I and II

Which of the following statements regarding altitude and climate are TRUE? I. Species composition on different sides of a mountain range are often different from each other. II. Rain shadows may appear on one side of a mountain range. III. The higher the altitude, the warmer the climate. IV. Both sides of a mountain range generally receive equal amounts of precipitation.

only I and II

Which of the following factors account for the inefficiency of the rate of photosynthesis? I. Even when conditions are ideal, the pigments that drive photosynthesis can absorb only a fraction of the light wavelengths available and thus a fraction of the total energy received. II. Plants in equatorial biomes have drastically reduced photosynthetic rates in winter. III. If conditions get dry, stomata close to conserve water. IV. The efficiency of enzymes is not temperature dependent.

only I and III

Detritus can be consumed by which of the following primary decomposers? I. bacteria II. archaea III. fungi IV. earthworms

only I, II, III, and IV

Why are changes in the global carbon cycle important? I. Burning reduces available carbon for primary producers and, therefore, primary consumers. II. Deforestation and suburbanization reduce an area's net primary productivity. III. Increasing atmospheric concentrations of carbon dioxide could alter Earth's climate. IV. By using fossil fuels we are destroying a nonrenewable resource.

only I, II, III, and IV

Based on the data in the accompanying figure, which of the following statements are correct? I. Area 1 has more average precipitation than Area 2. II. Area 1 has a higher average temperature than Area 2. III. Both areas have low variation in monthly precipitation. IV. Area 2 has a lower annual temperature variation compared to Area 1.

only I, II, and III

Which statements about K are correct? I) K varies among populations. II) K varies in space. III) K varies in time. IV)K is constant for any given species.

only I, II, and III

Which of the following consume other living organisms? I. primary producers II. herbivores III. carnivores IV. decomposers

only II and III

Based on the data in the accompanying figure, which of the following statements are correct? I. Area 1 would be considered a desert because of its high average temperature. II. Area 1 has more average precipitation than Area 2. III. Area 2 would be considered a desert because of its low average precipitation. IV. Area 2 has a larger annual temperature variation.

only II, III, and IV

Based on the experiment in the accompanying figure, which of the following are plausible reasons for the result? I. No nutrients evaporate now that vegetation is absent. II. Nutrients dissolve in the water running through the watershed. III. Nutrients are attached to small particles of sand or clay that leave the watershed. IV. Plant roots that held soil particles in place are no longer there.

only II, III, and IV

Which of the following statements regarding the future of populations in developing countries are correct? I. The fecundity is predicted to increase. II. Survivorship will increase. III. Overall population size will increase dramatically. IV. The number of offspring each year is predicted to remain high.

only II, III, and IV

In the map above, where will the weather be wetter? I. near 30° N II. near 30° S III. near the Equator

only III

Telomere shortening is a problem in which types of cells?

only eukaryotic cells

Which habitat type in the figure makes available the most new tissue to consumers?

open ocean

Which habitat types in the accompanying figure cover the largest area?

open ocean

Feeding behavior with a high-energy intake-to-expenditure ratio is called ________.

optimal foraging

Which of the following are considered apes?

orangutans

As you are on the way to Tahiti for a vacation, your plane crash-lands on a previously undiscovered island. You soon find that the island is teeming with unfamiliar organisms, and you, as a student of biology, decide to survey them (with the aid of the Insta-Lab Portable Laboratory you brought along in your suitcase). You select three organisms and observe them in detail, making the notations found in the accompanying table. Which organism would you classify as an animal?

organism C

The giant sloth described by Georges Cuvier suggests that ________.

organisms could go extinct

Activator proteins in eukaryotes usually have a domain that binds to DNA and other activation domains that often bind to ________.

other regulatory proteins

To reproduce, many plants produce seeds-structures containing embryonic offspring along with nutrients inside a tough case. These offspring develop after being released by the parent plant. To which animal reproductive strategy is seed production most comparable?

oviparous reproduction

Most fish deposit fertilized eggs, but some sharks keep the fertilized egg inside the female until she gives birth to a relatively well-developed pup. These sharks would thus be characterized as ________.

ovoviviparous

Which structure is common to both gymnosperms and angiosperms?

ovule

According to the phylogenetic tree in the accompanying figure, G. intestinalis constitutes a ________ group.

paraphyletic

What is the characteristic feature of the Chlamydiales phylum?

parasitic life cycle

The product of the lacI gene functions most like a car's ________.

parking brake

Your brother has just purchased a new plastic model airplane. He places all the parts on the table in approximately the positions in which they will be located when the model is complete. His actions are analogous to which process in development?

pattern formation

Upon returning to its hive, a European honeybee communicates to other worker bees the presence of a nearby food source it has discovered by ________.

performing a round dance

Karl von Frisch demonstrated that European honeybees communicate the location of a distant food source by ________.

performing a waggle dance with a run length proportionate to the food distance

Within a double-stranded DNA molecule, adenine forms hydrogen bonds with thymine and cytosine forms hydrogen bonds with guanine. This arrangement ________.

permits complementary base pairing

The duplication of homeotic (Hox) genes has been significant in the evolution of animals because it ________.

permitted the evolution of novel forms

Mendel studies seven different traits in the garden pea. What genetic term is used to describe an observable trait, such as those studied by Mendel?

phenotype

Encouraging the growth (via nutrient fertilization) of photosynthetic protists in marine environments may help reduce global warming because ________.

photosynthetic protists fix atmospheric carbon dioxide, decreasing atmospheric carbon dioxide levels

A prokaryote that obtains energy from light is a(n) ________.

phototroph

The approach to estimating phylogenetic trees is most like the approach of which species concept?

phylogenetic species concept

On the basis of their morphologies, how might Linnaeus have classified the Hawaiian silverswords? Linnaeus would have ________.

placed more of them in different genera than modern botanists do

You own 300 acres of patchy temperate forest. Which one of the following actions would increase the net primary productivity of the area the most?

planting 500 new trees

Some green algae exhibit alternation of generations. All land plants exhibit alternation of generations. No charophytes (stoneworts) exhibit alternation of generations. Keeping in mind the recent evidence from molecular systematics, the correct interpretation of these observations is that ________.

plants evolved alternation of generations independently of charophytes

Many identical copies of genes cloned in bacteria are produced as a result of ________.

plasmid and bacterial cell replication

At which stage of a basidiomycete's life cycle would reproduction be halted if an enzyme that prevented the fusion of hyphae was introduced?

plasmogamy

Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?

pleiotropy

Which of the following describes the ability of a single allele to have multiple phenotypic effects?

pleiotropy

You find a multilegged animal in your garden and want to determine if it is a centipede or a millipede. You take the animal to a university where a myriapodologist quickly tells you that you have found a centipede. Which of the following may have allowed her to make this distinction?

poisonous fangs

Entrepreneurs attempted, but failed, to harvest nuts from plantations grown in Southeast Asia. Attempts to grow Brazil nut trees in South American plantations also failed. In both cases, the trees grew vigorously, produced healthy flowers in profusion, but set no fruit. Consequently, what is the likely source of the problem?

pollination failure

A paleontologist has recovered a bit of tissue from the 400-year-old preserved skin of an extinct dodo (a bird). To compare a specific region of the DNA from the sample with DNA from living birds, which of the following would be most useful for increasing the amount of dodo DNA available for testing?

polymerase chain reaction (PCR)

Most causes of speciation are relatively slow, in that they may take many generations to see changes, with the exception of ________.

polyploidy

According to the logistic growth equation dN/dt = rmaxN(K — N)/K, A) the number of individuals added per unit time is greatest when N is close to zero. B) the per capita growth rate (r) increases as N approaches K. C) population growth is zero when N equals K. D) the population grows exponentially when K is small. E) the birth rate (b) approaches zero as N approaches K.

population growth is zero when N equals K.

In septate fungi, what structures allow cytoplasmic streaming to distribute needed nutrients, synthesized compounds, and organelles throughout the hyphae?

pores in septa

The arabinose operon (ara) provides a particularly interesting example of ________ in that when arabinose is present in the environment, the operon is transcribed.

positive control

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). If the molecular data best reflect the evolutionary history of these two groups, then the morphological similarities of these two species is most likely due to ________.

possession of homoplasic (convergent) traits

Which of the following is a characteristic of all chordates at some point during their life cycle?

post-anal tail

Which of the following levels of gene expression allows the most rapid response to environmental change?

post-translational control

Which of the following are important biotic factors that can affect the structure and organization of biological communities?

predation, competition

Microbiologists use the Gram stain to aid in the identification of bacteria. What is the major difference between Gram-positive and Gram-negative bacteria?

presence or absence of outer plasma membrane

The normal function of a tumor suppressor gene is to ________.

prevent progression of the cell cycle unless conditions are right for moving forward

The HIV protease has been the target of several anti-HIV medications called protease inhibitors. This antiviral strategy is possible because protease inhibitors ________.

prevent the formation of active viral proteins

What is the main advantage of controlled burnings of forested areas? Controlled burnings ________.

prevent the overgrowth of the underbrush

Which of the following is found in many tetrapods but not in fish?

production of amniotic eggs

What organisms are most numerous on Earth?

prokaryotes

A biologist develops a new drug that seems to dramatically slow the onset of symptoms resulting from HIV infection. Close monitoring of HIV-infected cells reveals that the viral proteins are in the form of long polyproteins. The biologist most likely developed a ________.

protease inhibitor

Eukaryotes have three nuclear RNA polymerases. The primary function of RNA polymerase II is transcription of ________

protein-coding genes

A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that ________.

proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU

Protists and bacteria are grouped into different domains because ________.

protists have a membrane-bounded nucleus, which bacterial cells lack

In adult arthropods, the hemocoel ________.

provides space for the internal organs to grow and function

If you ask a question about behavior that concerns how it works or what its mechanism is, you are asking a question that involves ________.

proximate causation

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. If true-breeding red long radishes are crossed with truebreeding white oval radishes, the F1 will be expected to be which of the following?

purple and long

When the birth rate is equal to each woman producing exactly enough offspring to replace herself and her offspring's father, and the birth rate is sustained for a generation, then ________.

r = 0 and there is zero population growth

Logistic growth of a population is represented by ΔN/Δt = ________.

rN*(k-n)/k

The central nervous system is lacking in animals that have ________.

radial symmetry

Which of the following most often controls the rate of nutrient cycling in ecosystems?

rate of decomposition of detritus

Which of the following are the most abundant and diverse of the extant vertebrates?

ray-finned fishes

Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6022 yellow and 2001 green (8023 total). The allele for green seeds has what relationship to the allele for yellow seeds?

recessive

How do chromatin-remodeling complexes recognize the genes they should act on? Chromatin-remodeling complexes ________.

recognize specific transcription factors bound to regulatory sequences of DNA

Imagine that you are searching for the gene associated with nail-patella syndrome, a dominant genetic disorder that causes developmental abnormalities. In a large pedigree you discover an association between nail-patella syndrome and a genetic marker that occurs in two different alleles, A and B. Fifteen individuals within this pedigree have nail-patella syndrome and are A/B heterozygotes for the marker. Thirty individuals within this pedigree don't suffer from nail-patella syndrome and are homozygous for the A marker allele. One individual within this pedigree has nail-patella syndrome and is also homozygous for the A marker allele. The most likely explanation for this exceptional individual is that ________.

recombination occurred between the nail-patella gene and marker locus in one of the parents of the exceptional individual

Which of the following groups would be most likely to exhibit uniform dispersion?

red squirrels, which actively defend territories

The functional role of sporopollenin is primarily to ________.

reduce dehydration

The best classification system is that which most closely ________.

reflects evolutionary history

What is the primary mechanism by which eukaryotes control transcription during cellular differentiation?

regulatory transcription factors that influence chromatin structure and bind to regulatory regions

Use the following description to answer the question below. On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, but hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago. If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are poorly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, these conditions will most likely lead to ________.

reinforcement

The bulk of the sequence data in whole-genome sequencing directly comes from ________.

relatively small (~1000 base-pair) sequences cloned into plasmids

When nonrandom mating occurs in a population so that individuals prefer to mate with similar individuals, allele frequencies should

remain the same, but homozygotes will be overrepresented in the population.

The epsilon (ε) subunit of DNA polymerase III of E. coli has exonuclease activity. How does it function in the proofreading process? The epsilon subunit ________.

removes a mismatched nucleotide

Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise?

replication without separation

Which of the following is a protein produced by a regulatory gene?

repressor

As you study two closely related predatory insect species, the two-spot and the three-spot avenger beetles, you notice that each species seeks prey at dawn in areas without the other species. However, where their ranges overlap, the two-spot avenger beetle hunts at night and the three-spot hunts in the morning. When you bring them into the laboratory and isolate the two different species, you discover that the offspring of both species are found to be nocturnal. You have discovered an example of ________.

resource partitioning

If a tunicate's pharyngeal gill slits were suddenly blocked, the animal would have trouble ________.

respiring and feeding

In most fungi, karyogamy does NOT immediately follow plasmogamy, which consequently ________.

results in heterokaryotic or potentially even dikaryotic cells

A virus consisting of a single strand of RNA, which is transcribed into complementary DNA, is a ________.

retrovirus

Because they both produce a reverse transcriptase, long interspersed nuclear elements (LINEs) as transposable elements may be related to ________.

retroviruses

Which viruses have single-stranded RNA that acts as a template for DNA synthesis?

retroviruses

If mRNAs could be ligated and replicated within plasmids, what enzyme commonly used in recombinant DNA technology would no longer be needed?

reverse transcriptase

The antennae of insects have a function most similar to that of ________.

rhinophores

What molecules in the spliceosome catalyze the intron removal reactions?

ribozymes

Which of these time intervals, based on plant fossils, came last (most recently)?

rise and diversification of angiosperms

Exponential growth of a population is represented by ΔN/ Δt = ________.

rmax N

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?

roan × roan

Considering its total area covered, which ecosystem type represented in the figure has a very low level of economic impact on Earth's ecosystem, assuming that NPP is positively correlated with economic value?

rock, sand, and ice

Which of the pairs of plant structures below are homologous?

rose bush leaf and oak tree leaf

Recent research has shown that von Frisch was not completely correct about the difference between the round dance and waggle dance. The new information suggests that in honeybees, the ________.

round dance communicates direction as well as distance

Which abiotic factor would have the most significant acute physiological effect on migrating salmon as they move from saltwater to freshwater?

salinity differences

Fungi that absorb nutrients from decaying plant matter are called ________.

saprobes

Which one of the following animals would most likely be defined as a keystone species?

sea otter

An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates-a parrotfish and a clownfish. She arranged for daily feedings of copepods and feeder fish. The bivalves started to die one by one; only the undamaged shells remained. To keep the remaining bivalves alive, the teacher would most likely need to remove the ________.

sea star

If a kelp farmer wanted to maximize her harvest, which type of echinoderm would she be most concerned about in the habitat?

sea urchins

If the midbrain of a fish became damaged it would harm its ability to ________.

see

Some researchers have begun attempting to clean up oil spills by adding nonindigenous microbial hydrocarbon degraders to the spill, in the hope that these bacteria will neutralize the dangerous chemicals in the spill. This is an example of ________

seeding

Which morphological trait evolved more than once in animals, according to the phylogeny based on DNA sequence data found in the accompanying figure?

segmentation

DNA is synthesized through a process known as ________.

semiconservative replication

A laboratory might use dideoxyribonucleotides to ________

sequence a DNA fragment

What is metagenomics?

sequencing DNA from a group of species from the same ecosystem

The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different ________

sets of regulatory proteins

In eukaryotic cells, transcription cannot begin until ________.

several transcription factors have bound to the promoter

If the pond organisms are larvae, rather than adults, Sarah should expect them to have all of the following structures, EXCEPT ________.

sex organs

Suppose you traveled back in time and located the first animals to have evolved feathers. You found that these animals were tree-dwelling ectotherms, able to run quickly but unable to fly. You also noticed that only males had feathers. Which hypothesis of feather evolution would these data most support? Feathers initially evolved in a role associated with ________.

sexual selection

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? Dogs and wolves ________.

share a very recent common ancestor

When using a cladistic approach to systematics, which of the following is considered most important for classification?

shared derived characters

What is the main structural difference between enveloped and nonenveloped viruses?

Enveloped viruses have a phospholipid membrane outside their capsid, whereas nonenveloped viruses do not have a phospholipid membrane.

Which of the following organisms would be most likely to fossilize?

a common squirrel

In the map above, which region would have milder weather than expected without the ocean currents?

Europe

What group of mammals have (a) embryos that spend more time feeding through the placenta than the mother's nipples, (b) young that feed on milk, and (c) a prolonged period of maternal care after leaving the placenta?

Eutheria

Which of the following statements is consistent with the principle of competitive exclusion?

Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species

Which of the following statements best summarizes evolution by natural selection as it is viewed today?

Evolution by natural selection is the differential survival and reproduction of the most-fit phenotypes.

Which of the graphs shown best represents the relationship between the intensity of directional selection and the genetic variation present within a population?

Graph B

Considering the global carbon cycle, where are humans having a great impact? I. terrestrial ecosystems II. oceans III. atmosphere

I, II, and III

For a species to be called "invasive," it must ________. I. be introduced to a new area II. spread rapidly in this new area III. compete with native species successfully

I, II, and III

With which of the following statements would a biologist be most inclined to agree?

Humans and other apes represent divergent lines of evolution from a common ancestor.

Under what condition is the AraC protein an activator?

The AraC protein is an activator when it is bound to arabinose.

Which of the following statements regarding the figure shown is TRUE?

Species richness should be higher on larger islands close to the mainland.

Refer to the accompanying art to answer the question below. According to the Shannon Diversity Index, which of the five blocks shown, with each containing 36 squares, would show the greatest diversity?

5

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is ________.

AAA

Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?

India was a separate continent until 45 million years ago.

Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. (a) What is the most probable genotype of each parent? (b) Based on your answer in (a) above, what genotypic and phenotypic ratios are expected in these progeny? (Assume the following symbols: G = gray and g = white.)

(a) Gg × Gg; (b) genotypic = 1:2:1, phenotypic = 3:1

A population of ground squirrels has an annual per capita birth rate of 0.06 and an annual per capita death rate of 0.02. Calculate an estimate of the total number of individuals added to (or lost from) a population of 1000 individuals in one year.

40 individuals added

Cells were infected with approximately 1000 copies of either virus A or virus B at the 0 time point. At 5-minute intervals, a sample of the virus and cell mixture was removed. The intact cells were removed from the sample, and the number of viruses per milliliter of culture was determined. Using the data in the figure, how long does it take for virus A to go through one lytic cycle?

45 minutes

Suppose 64 percent of a remote mountain village can taste phenylthiocarbamide (PTC) and must, therefore, have at least one copy of the dominant PTC taster allele. If this population conforms to Hardy—Weinberg expectations for this gene, what percentage of the population must be heterozygous for this trait?

48 percent

In the accompanying figure, which number would designate the arctic tundra biome?

5

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?

A gene from an organism can theoretically be expressed by any other organism.

Which of the following contradicts the one-gene, one-enzyme hypothesis?

A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally.

During elongation, which site in the ribosome represents the location where a codon is being read?

A site

How does termination of translation take place?

A stop codon is reached.

The Panama Canal was completed in 1914, and its depth is about 50 feet. After 1914, snapping shrimp species from which habitats should be most likely to form hybrids as the result of the canal?

A1 and B1

Which of these habitats is likely to harbor the most recently diverged species?

A1 and B1

Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell?

AIDS

After looking at the accompanying figure, what can be said about productivity in this ecosystem?

About 90% of the energy is lost between most trophic levels.

You run an osteology lab, where students are able to study the bone structure of various species. To produce clean bones, you introduce insects and bacteria to remove all remaining flesh. Which bacteria would be the best purchase for your lab?

Actinobacteria

A biologist trying to determine the mechanism of adenosine triphosphate (ATP) production in a newly discovered bacterium provides several different substrates on which the bacteria can feed. Which of the following results would indicate that the species uses fermentation to produce ATP?

After exposure to amino acids, the bacteria produce a smell like rotting flesh.

A black guinea pig crossed with an albino guinea pig produced twelve black offspring. When the albino was crossed with a second black animal, six blacks and six albinos were obtained. What is the best explanation for this genetic situation?

Albino is recessive; black is dominant.

Evolution in a population of island iguanas can be caused by the following agent(s):

All of the above can be agents

The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following?

All of the genes controlling the traits behaved as if they were on different chromosomes

In the accompanying figure, which of the lines represents exponential growth?

All of the lines represent exponential growth.

Which major eukaryotic lineages form the Bikonta, a monophyletic group characterized by two flagella as a synapomorphy?

Alveolata, Stramenopila, Rhizaria, Plantae, Excavata

For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work?

Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

What is the difference between an epidemic and a pandemic?

An epidemic is restricted to a local region; a pandemic is global.

Which of the following is required for a behavioral trait to evolve by natural selection?

An individual's reproductive success depends in part on how the behavior is performed.

For many years, scientists believed that almost all animal lineages burst into being during the Cambrian era (just after the end of the Precambrian super eon). However, there have been many recent findings of animal-like fossils and "trace fossils" (fossils of an animal-like organism's movement) from the late Precambrian. Which of the following best explains why it took so long to realize there was animal-like life in the Precambrian?

Animals from the late Precambrian had soft bodies.

Which of the following statements explains why animals are less likely than plants to speciate by polyploidy?

Animals self-fertilize less often than plants, so diploid gametes are less likely to fuse.

Which zone produces the most global oxygen gas?

B

Suppose there was a mutation in the segment-polarity genes of Drosophila. What do you suppose might be the outcome?

Antennae will appear in a different part of their usual segment

The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur?

Anterior structures would form in both ends of the embryo.

Which of the following is TRUE of the life cycle of mosses?

Antheridia and archegonia are produced by gametophytes.

Treehoppers (a type of insect) produce honeydew, which ants use for food. Treehoppers have a major predator, the jumping spider. Researchers hypothesized that the ants would protect the treehoppers from the spiders. In an experiment, researchers followed study plots with ants removed from the system and compared them to a control plot. In the figure shown, what can you conclude?

Ants do somehow protect the treehoppers from spiders.

Genetic drift occurs in a population. Which of the following statements might be TRUE?

Any of these statements can be true.

In the accompanying figure, what can be stated about species diversity and latitude?

As latitude increases, diversity decreases.

The proteome is all the proteins produced by an organism. The genome is the totality of all genes of an organism. If the proteome is much larger than the genome, which of the following statements would be accurate?

At least in some cases, a single gene must code for more than one protein.

Which of the following classes is comprised of carnivorous predators that are able to extend their stomachs through their mouths to feed?

Asteroidea

Based on the diagrams in the figure shown and on the large population of baby boomers in the United States, which graph best reflects U.S. population in 20 years?

B

Use the following diagram of a hypothetical food web to answer the question(s) below. The arrows represent the transfer of energy between the various trophic levels. Which letter represents an organism that could be a producer?

B

________ form ectomycorrhizal relationships with temperate forest trees while ________ form arbuscular (endomycorrhizal) relationships with plants in grasslands and tropical forests.

Basidiomycetes; glomeromycetes

While traveling in Texas, you stumble across a snake with red, yellow, and black bands. You somehow remember that this could be a poisonous coral snake or a harmless milk snake, but you forget how to differentiate them because they both have similar colors and banding patterns. You wisely decide not to pick up the snake. What defense of the snake was successful in preventing you from grabbing the snake?

Batesian mimicry

When the Bicoid protein is expressed in Drosophila, the embryo is still syncytial (divisions between cells are not yet fully developed). This information helps to explain which observation by Nüsslein-Volhard and Wieschaus?

Bicoid protein diffuses throughout the embryo in a concentration gradient.

Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small vertebrates that fly or jump out of the way of the ants. What is the result of the association between birds and ants?

Birds benefit from the association but have no impact on the ants.

What is the only group of Mollusca that does NOT have a radula?

Bivalves

Use the following description to answer the question below. On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. What is the best way to promote fusion between two related populations of mosquitofish, one of which lives in a predator-rich pond and the other of which lives in a predator-poor pond?

Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.

Scientists have found that the lifetimes of mRNAs coding for pair-rule regulatory elements in Drosophila embryos may last only a few minutes. What does this suggest about the overall developmental plan of an animal body?

Building an animal body requires a sequence of precisely timed steps.

How do altruistic behaviors arise through natural selection?

By his or her actions, the altruist increases the likelihood that some of its genes will be passed on to the next generation.

An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates-a parrotfish and a clownfish. She arranged for daily feedings of copepods and feeder fish. The clownfish readily swims among the tentacles of the sea anemones; the parrotfish avoids them. One hypothesis for the clownfish's apparent immunity is that they slowly build a tolerance to the sea anemone's toxin. A second hypothesis is that a chemical in the mucus that coats the clownfish prevents the nematocysts from being triggered. Which of the following graphs supports the second, but not the first, of these hypotheses?

C

Many amphibian populations have been decimated by a parasitic fungus classified as a member of the ________.

Chytridiomycota

You observe the gametes of a fungal species under the microscope and realize that they resemble animal sperm. To which of the following groups does the fungus belong?

Chytrids

Based on the accompanying figure, which of the following statements correctly interprets the data?

Clutch size decreases as female density increases.

Codons are three-base sequences that specify the addition of a single amino acid. How do eukaryotic codons and prokaryotic codons compare?

Codons are a nearly universal language among all organisms.

In the accompanying figure, where do we find the highest species richness?

Communities 2 and 4

In the figure shown, which community has the highest species diversity?

Community 2

Regarding soil and organic matter in humus, which of the following statements is TRUE?

Completely decayed soil organic matter is called humus

Which of the following statements is TRUE of the pine life cycle?

Conifer pollen grains contain male gametophytes.

A cage containing male mosquitoes has a small earphone placed on top, through which the sound of a female mosquito is played. All the males immediately fly to the earphone and go through all of the steps of copulation. What is the best explanation for this behavior?

Copulation is a fixed action pattern, and the female flight sound is a sign stimulus that initiates it.

Which of the following scenarios would provide the most relevant data on population density?

Count the number of pine trees in several randomly selected 10-meter-square plots and extrapolate this number to the fraction of the study area these plots represent.

Which of the following groups is classified as Homo sapiens?

Cro-Magnons

In the figure, which graph of soil nitrogen loss over time most strongly supports the hypothesis that if the 20-cm-tall Dawsonia acts as a physical buffer, then it reduces water's ability to erode the soil and carry away its nitrogen?

D

Which of the following is in the correct order for one cycle of polymerase chain reaction (PCR)?

Denature DNA; anneal primers; extend primers.

Why do populations grow more slowly as they approach their carrying capacity?

Density-dependent factors lead to fewer births and increased mortality.

If cells of an individual contain the same set of genes, how do these cells become different from each other during development?

Differences in extracellular signals received by each cell lead to differences in the types of regulatory proteins present in each cell.

Recall that Clements's view of biological communities is that of a highly predictable and interrelated structure, while Gleason's view of biological communities is that individual species operate independently. If we set up many identical sterilized ponds in the same area and allowed them to be colonized, what should we predict if we wished to test Gleason's hypothesis?

Different plankton communities will develop in all ponds.

Which of these statements about human evolution is correct?

Different species of the genus Homo have coexisted at various times throughout hominin evolution.

Protists from which of the following taxonomic groups are most likely to lead to paralytic shellfish poisoning?

Dinoflagellata

In the figure above, which direction will have a desert biome?

East

In the figure above, which direction will have a rain shadow?

East

Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?

Energy transfer between trophic levels is usually less than 20 percent efficient.

Elephants are not the most dominant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands convert to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following describes why elephants are the keystone species in this scenario?

Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance.

Why is energy lost when herbivores eat primary producers?

Energy is lost because most of the total energy consumed is used for cellular respiration rather than growth and reproduction

Which of the following would be most significant in understanding the structure of an ecological community? I. determining how many species are present overall II. determining which particular species are present III. determining the kinds of interactions that occur among organisms of different species IV. determining the relative abundance of species

I, II, III, and IV

Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme (endonuclease)?

GGCC CCGG

Why is it more difficult to treat fungal infections than bacterial infections in humans?

Fungal and animal cells and proteins are similar. Thus, drugs that disrupt fungal cell or protein function may also disrupt human cell or protein function.

How does a swim bladder help the ray-finned fishes maintain buoyancy?

Gas is added to the bladder as the fish's depth increases.

Which of the following is an important role for fungi in the carbon cycle?

Fungi release fixed carbon back to the environment for other plants and photosynthetic organisms to utilize.

Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?

Fungi secrete extracellular enzymes that can break down large molecules.

Considering the paragraph above, it is speculated that H. floresiensis and H. sapiens may have lived on Flores concurrently. Suppose researchers obtained mitochondrial DNA samples from the H. floresiensis remains, amplified a 1000-base-pair sequence via PCR, and compared it to that of several currently living H. sapiens native to Indonesia, North Africa, and North America. Also suppose H. floresiensis were found to differ from the average Indonesian H. sapiens in 28 base pairs, from the average North African H. sapiens in 51 base pairs, and from the average North American H. sapiens in 53 base pairs, while two randomly selected H. sapiens differed from each other in an average of 21 base pairs. What conclusions would you draw from these data?

H. floresiensis and H. sapiens probably lived on Flores concurrently and interbred to some degree.

It is believed that HIV has passed from chimps to humans more than once. This suggests that animal-to-human viral transmissions may be more common than previously thought. What is the best evidence in support of the conclusion that HIV made the chimp-to-human leap more than once?

HIV has multiple strains, and the virus does not appear to be able to leap from humans back to chimps.

Why do scientists consider HIV to be an emerging virus?

HIV suddenly became apparent and widespread in the 1980s.

A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?

HT

Why do moderate levels of disturbance result in an increase in community diversity?

Habitats are opened up for less competitive species.

In the accompanying figure, which of the following statements is TRUE?

Half of the six insects shown are harmless.

Diatoms are mostly asexual members of the phytoplankton. They obtain their nutrition from functional chloroplasts, and each diatom is encased within two porous, glass-like valves. Which question would be most important for one interested in the day-to-day survival of individual diatoms?

How do diatoms with their glass-like valves keep from sinking into poorly lit waters?

Which tree depicts the microsporidians as a sister group of the ascomycetes?

I

Which of the following are TRUE about the greenhouse effect? I. High-energy solar radiation enters the atmosphere. II. Some of the energy is reflected, and some is absorbed by the Earth's surface. III. Heat is emitted as infrared radiation, and some of it is retained in the atmosphere, decreasing the temperature on Earth.

I and II

A population is correctly defined as having which of the following characteristics? I. inhabiting the same general area II. belonging to the same species III. possessing a constant and uniform density and dispersion

I and II only

Which of the following statements about species, as defined by the biological species concept, is (are) correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. All members of a species can potentially interbreed.

I and III

Animal communication involves what type of sensory information? I. visual II. auditory III. olfactory IV. tactile

I, II, III, and IV

Which of the following locations are large reservoirs for carbon for the carbon cycle? I. atmosphere II. sediments and sedimentary rocks III. fossilized plant and animal remains (coal, oil, and natural gas) IV. plant and animal biomass

I, II, III, and IV

Which of the following might affect the foraging behavior of an animal in the context of optimal foraging? I. risk of predation II. prey size III. prey defenses IV. prey density

I, II, III, and IV

Refer to the study by Poulsen et al. and the accompanying figure. Latrunculin A is a reversible toxin that disrupts the formation of actin fibers. A culture of a particular species of diatom was treated with this toxin diluted in a buffer, while another culture was treated only with the buffer (no toxin; control). The motility of cells in each culture was assessed by counting the number of cells that were moving during a defined period of time. Which of the following conclusions is reasonable based on the figure?

In this species of diatom, fully formed actin fibers are necessary for movement.

You believe that you have isolated a new strain of positive-sense, single-stranded RNA virus and set about studying it in your laboratory. Which of the following lines of evidence would most strongly support your hypothesis that the virus is a [+]ssRNA?

Introducing a protease inhibitor causes the virus to stop producing proteins and reproducing.

Which of these four gene parts should allow the construction of the most accurate phylogenetic tree, assuming that this is the only part of the gene that has acted as a reliable molecular clock?

Intron VI

As scientists were unraveling the mysteries associated with transcription and translation in eukaryotes, they discovered there was not a one-to-one correspondence between the nucleotide sequence of a gene and the base sequence of the mRNA it codes for. They proposed the genesin-pieces hypothesis. How can the genes-in-pieces hypothesis be explained?

Introns are noncoding segments of DNA that are present in the initial transcript, but are removed by splicing.

Imagine that a deep temperate-zone lake did not turn over during the spring and fall seasons. Based on the physical and biological properties of limnetic ecosystems, what would be the difference from normal seasonal turnover?

Lakes would suffer a nutrient depletion in surface layers

A team of researchers developed a poison effective against lamprey larvae in freshwater cultures. The poison is ingested and causes paralysis by detaching segmental muscles from the skeletal elements. The team wants to test the poison's effectiveness in streams feeding Lake Michigan, but one critic worries about potential effects on lancelets, which are similar to lampreys in many ways. Why is this concern misplaced?

Lancelets live only in saltwater environments.

Looking at the data in the accompanying figure, what can be said about survival and clutch size?

Large clutch size correlates with low survival.

Why are food chains relatively short?

Longer chains are less stable and energy transfer between trophic levels is inefficient.

Which of the following is the most important assumption for the mark-recapture method to estimate the size of wildlife populations?

Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase

What is the difference between a linkage map and a physical map?

Markers are spaced by recombination frequency on a linkage map and by number of base pairs on a physical map

How do mass extinctions differ from background extinctions?

Mass extinctions cause a larger proportion of organisms to go extinct than background extinctions.

Which one of the following is a lophotrochozoan?

Mollusks

In what way are monotremes similar to more ancestral chordate lineages, as opposed to more recently evolved mammals?

Monotremes lay eggs; other mammals bear live young

What does it mean when we say the genetic code is redundant?

More than one codon can specify the addition of the same amino acid.

You have before you a living organism, which you examine carefully. Which of the following should convince you that the organism is acoelomate?

Muscular activity of its digestive system distorts the body wall.

In 1986, a nuclear power accident in Chernobyl, USSR (now Ukraine), led to high radiation levels for miles surrounding the plant. The high levels of radiation caused elevated mutation rates in the surviving organisms, and evolutionary biologists have been studying rodent populations in the Chernobyl area ever since. Based on your understanding of evolutionary mechanisms, which of the following most likely occurred in the rodent populations following the accident?

Mutation led to increased genetic variation.

Which of the following statements about evolution of behavior is correct?

Natural selection will favor behavior that enhances survival and reproduction

The heartworms that can accumulate within the hearts of dogs and other mammals have a pseudocoelom, an alimentary canal, and an outer covering that is occasionally shed. To which phylum does the heartworm belong?

Nematoda

A student observes a wormlike organism crawling about on dead organic matter. Later, the organism sheds its outer covering. One possibility is that the organism is a larval insect (like a maggot). However, it might be a member of the phylum ________, and one way to distinguish between the two possibilities is by looking for the presence or absence of ________.

Nematoda; a circulatory system

You acquire a soil sample and run an enrichment culture on it. You provide the organisms in the culture with all of the ingredients required for growth except for nitrogen. What result do you expect to have at the end of your experiment?

Nitrogen-fixing bacteria will significantly outnumber those incapable of fixing nitrogen.

In a small population of alpine foxes, you observe increased ear length over a 10-year period. Can you conclude that increase in ear length is advantageous in this population?

No.

The peppered moth provides a well-known example of natural selection. The light-colored form of the moth was predominant in England before the Industrial Revolution. In the midnineteenth century, a dark-colored form appeared. The difference is produced by a dominant allele of one gene. The dark- and light-colored forms readily interbreed with each other. By about 1900, approximately 90 percent of the moths around industrial areas were dark colored, whereas light-colored moths were still abundant elsewhere. Apparently, birds could readily find the light moths against the soot-darkened background in industrial areas and, therefore, were eating more light moths. Recently, use of cleaner fuels has greatly reduced soot in the landscape, and the dark-colored moths have been disappearing. Should the two forms of moths be considered separate species?

No.

Use the following information to answer the question below. Researchers studying a small milkweed population note that some plants produce a toxin and other plants do not. They identify the gene responsible for toxin production. The dominant allele (T) codes for an enzyme that makes the toxin, and the recessive allele (t) codes for a nonfunctional enzyme that cannot produce the toxin. Heterozygotes produce an intermediate amount of toxin. The genotypes of all individuals in the population are determined (see chart) and used to determine the actual allele frequencies in the population. Refer to the accompanying figure. Is this population in Hardy—Weinberg equilibrium?

No; there are more homozygotes than expected.

Why did the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?

One allele was dominant.

In humans, blue eyes are inherited as a recessive autosomal trait and color blindness is an Xlinked recessive trait. A woman with blue eyes and normal color vision whose father was colorblind marries a man who also has normal color vision. He has brown eyes, but his mother had blue eyes. Which of the following would you expect to be TRUE for their sons?

One-fourth of their sons will be color-blind and have blue eyes, one-fourth of their sons will be color-blind and have brown eyes, one-fourth of their sons will have normal color vision and blue eyes, one-fourth of their sons will have normal color vision and brown eyes.

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their twenties. How likely is it for a woman to have this condition?

One-half of the daughters of an affected father and a carrier mother could have this condition.

In humans, blue eyes are inherited as a recessive autosomal trait and color blindness is an Xlinked recessive trait. A woman with blue eyes and normal color vision whose father was colorblind marries a man who also has normal color vision. He has brown eyes but his mother had blue eyes. Which of the following would you expect to be TRUE for their daughters?

One-half of their daughters will have normal color vision and brown eyes; one-half of their daughters will have normal color vision and blue eyes.

In early forensic applications of DNA fingerprinting, DNA was extracted from crime scene material, digested with restriction enzymes, and then used to prepare a Southern blot. Today, polymerase chain reaction (PCR) is used in the early steps of forensic DNA analysis. Which of the following is an advantage that PCR provides over the former method?

PCR requires much less DNA for analysis.

Multicellularity and large body size of eukaryotic organisms require high metabolic rates and efficient ATP production by aerobic respiration. How did bacteria change Earth's atmosphere to enable aerobic respiration?

Oxygenic photosynthesis by cyanobacteria significantly increased the amount of oxygen in the atmosphere.

According to bottom-up and top-down control models of community organization, which of the following expressions would imply that an increase in the size of a carnivore (C) population would negatively impact its prey (P) population, but not vice versa?

P ← C

What is a primary difference between polymerase chain reaction (PCR) and traditional cloning procedures such as those used to clone the human growth hormone gene?

PCR eliminates the need for restriction enzymes, vectors, and cells

Which of the following protist lineages is appropriately paired with its supportive and/or protective structure?

Parabasalids have an internal support rod, made of cross-linked microtubules, that runs the length of the cell.

The largest extinction, measured as a percentage of species that disappeared, occurred at the end of which geological period?

Permian

The major evolutionary episode corresponding most closely in time with the formation of Pangaea was the ________.

Permian extinctions

Which of the following best describes the physical relationship of the partners involved in lichens?

Photosynthetic cells are surrounded by fungal hyphae.

Why is speciation by polyploidy more likely in plants than in animals?

Plant gametes can be produced by meiosis from somatic cells that have undergone many rounds of mitosis.

The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when the hybrids mate with other hybrids or with adults of either species, they are rarely successful in producing offspring. What can you infer from this information?

Postzygotic isolation exists between the two frog species.

In a single polymerase chain reaction (PCR) cycle consisting of 15 seconds at 94°C, 30 seconds at 50°C, and 1 minute at 72°C, what is happening in the step run at 50°C?

Primers are annealing to the DNA to be amplified.

What is a major difference between eukaryotic DNA replication and prokaryotic DNA replication?

Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have multiple origins of replication.

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Proto-oncogenes normally help regulate cell division.

Since Watson and Crick described DNA in 1953, which of the following might best explain why the function of small RNAs (miRNAs) is still not well understood?

Recent advances in technology and our understanding of how DNA is expressed have made this possible.

Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize the amino acid phenylalanine. This amino acid is not naturally produced by humans. Therefore, the most efficient and effective treatment is which of the following?

Regulate the diet of the affected persons to severely limit the uptake of the amino acid.

In what general way are regulons regulated?

Regulons can be under either positive or negative control.

Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?

Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

Suppose that an induced mutation removes most of the 5' end of the 5' UTR of an mRNA. What is most likely to happen?

Removal of the 5' UTR also removes the 5' cap and the mRNA will quickly degrade.

Which is the best way to test the hypothesis that C. is competitively excluded from the lower intertidal zone by B. balanoides?

Remove all B. balanoides from the lower intertidal zone.

Theoretically, which would be the most effective way to disrupt a Hadley cell?

Remove all equatorial moisture and convection.

What does the graph in the accompanying figure tell you about the definition of a keystone species?

Removing a keystone species from the community drastically reduces diversity

In testing a hypothesis that "territorial defense in European robins is a fixed action pattern that is released by the sight of orange feathers," researchers found that robins defended their territory by attacking anything that was of similar size and had an orange patch. What experiment would you perform next to determine that the color initiated the defense response?

Repeat the experiment using a blue patch instead of an orange patch.

Which one of the following statements about RNA processing is TRUE?

Ribozymes may function in RNA splicing.

In large-scale, genome-wide association studies in humans we look for ________.

SNPs where one allele is found more often in persons with a particular disorder than in healthy controls

Which of the following is a prediction of the high-productivity hypothesis that is proposed to explain the latitudinal gradient in species diversity?

Speciation rates increase as niche differentiation occurs.

Mammals have a family between 500 and 1000 genes that encode receptor proteins on the surface of odor-receptor neurons. If all mammals have these genes, why do some mammals have a better sense of smell than others do?

Some of the genes may have been mutated and rendered inactive in some species but not in others.

What does this reclassification based on molecular data imply about the evolution of acoelomates, pseudocoelomates, and coelomates?

Some pseudocoelomates and acoelomates have evolved from coelomates

Suppose you have identified a type of lizard that seems to have acquired a mutation in which hindlimbs are absent. Which gene, also responsible for the loss of limbs in snakes, may be mutated in this animal?

Sonic hedgehog

A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have ________.

T4 protein and T4 DNA

A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have ________.

T4 protein and T4 DNA.

Telomere shortening puts a limit on the number of times a cell can divide. Research has shown that telomerase can extend the life span of cultured human cells. How might adding telomerase affect cellular aging?

Telomerase eliminates telomere shortening and retards aging.

What appears to be a dark side to telomerase activity with regard to human health?

Telomerase is active in most cancer cells.

What is believed to be the most significant result of the evolution of the amniotic egg?

Tetrapods were no longer tied to the water for reproduction.

Look at the graph for Scutigerina weberi (note the scale of the y-axis) in the accompanying figure. What is the best interpretation of these results?

The centipede had its spiracles open the entire time

Poliovirus is an RNA virus of the picornavirus group, which uses its RNA as mRNA. At its 5' end, the RNA genome has a viral protein (VPg) instead of a 5' cap. This is followed by a nontranslated leader sequence, and then a single long protein-coding region (~7000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short period use of the radioactive amino acids results in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides. What conclusion is most consistent with the results of the radioactive labeling experiment?

The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones.

Poliovirus is an RNA virus of the picornavirus group, which uses its RNA as mRNA. At its 5' end, the RNA genome has a viral protein (VPg) instead of a 5' cap. This is followed by a nontranslated leader sequence and then a single long protein-coding region (~7000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short-period use of the radioactive amino acids result in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides. What conclusion is most consistent with the results of the radioactive labeling experiment?

The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones.

If the Earth were to reorient such that the North Pole always received direct sunlight (always faced the Sun), how would that change Earth's climate?

The South Pole would get colder

The tRNA shown with the previous question has its 3' end projecting beyond its 5' end. What will occur at this 3' end?

The amino acid binds covalently.

An experimenter has altered the 3' end of the tRNA corresponding to the amino acid methionine in such a way as to remove the 3' bases AC. Which of the following hypotheses describes the most likely result?

The amino acid methionine will not become covalently bound.

Look at the graph for Cormocephalus morsitans in the accompanying figure. What is the best interpretation of these results?

The centipede had its spiracles open when carbon dioxide (CO2) emission peaked and closed when CO2 emission was low.

Why is terrestrial productivity higher in equatorial climates?

The answer is most likely a combination of the other responses

Which of the following statements best describes the effect of climate on biome distribution?

The average climate and pattern of climate are important in determining biome distribution

How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms?

The base sequence of DNA carries the information needed to code for proteins.

In the Morse code, a series of dots and dashes code for letters of the alphabet. How is this analogous to the genetic code?

The bases of DNA code for the more complex amino acid sequence of the proteins in cells.

Adaptations to terrestrial environments evolved independently in arthropods, mollusks, nematodes, and annelids. What logical conclusion would you make from this statement?

The common ancestor of all these groups was probably aquatic.

Which of the following is TRUE of all horizontally oriented phylogenetic trees, where time advances to the right?

The common ancestor represented by a branch point farther right existed more recently in time than the common ancestors represented at branch points located farther to the left.

The common ancestor of the protostomes had a coelom. What does this suggest?

The body cavity evolved before the lophophore.

In a healthy cell, the rate of DNA repair is equal to the rate of DNA mutation. When the rate of repair lags behind the rate of mutation, what is a possible fate of the cell?

The cell can be transformed to a cancerous cell.

Which of these fungal features supports the phylogenetic conclusion that fungi are more closely related to animals than to plants?

The cell walls of fungi are made of chitin.

If a cell were unable to produce histone proteins, which of the following would be a likely effect?

The cell's DNA couldn't be packed into its nucleus.

Based on the data in the figure, which of the following statements is TRUE?

The data from Area 2 describes a boreal forest.

In the experiment outlined in the accompanying table, what would you expect to happen if researchers supplied an enzyme that blocked the expression of the Dll gene?

The developing embryo would have no appendages.

Hutchinson—Gilford progeria is an exceedingly rare human genetic disorder in which there is very early senility and death, usually from coronary artery disease, at an average age of 13 years. Patients, who look very old even as children, do not live to reproduce. Which of the following represents the most likely assumption?

The disorder may be due to mutation in a single protein-coding gene.

You observe two female fish of the same species breeding. One female lays 100 eggs and the other female lays 1000 eggs. Which one of the following is LEAST likely given the limits of fitness trade-offs?

The eggs from the female laying 1000 eggs have larger yolks than the yolks of the eggs from the female laying 100 eggs

Suppose the pair-rule genes were inactivated in Drosophila embryos. What is the likely result of the experiment?

The embryos would have missing alternate segments.

Suppose the protein specified by bicoid was injected into Drosophila embryos so that a high concentration was present everywhere in the embryo. What might be the result of such an experiment?

The embryos would show no development of posterior regions.

According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to keep the engulfed cell alive, rather than digesting it as food?

The engulfed cell provided the host cell with adenosine triphosphate (ATP)

What conclusion is apparent from the data in the accompanying table?

The expansion in number of Hox genes throughout vertebrate evolution cannot be explained merely by three duplications of the ancestral vertebrate Hox cluster.

Graph (b) in the accompanying figure shows the normal fluctuations of a population of grouse. Assuming graph (a) in the figure is the result of some experimental treatment in the grouse population, what can be concluded?

The experimental treatment has most likely identified the cause of population cycling.

During a field trip, an instructor touched a moth resting on a tree trunk. The moth raised its forewings to reveal large eyespots on its hind wings. The instructor asked why the moth lifted its wings. One student answered that sensory receptors had fired and triggered a neuronal reflex culminating in the contraction of certain muscles. A second student responded that the behavior might frighten predators. Which statement best describes these explanations?

The first explanation refers to proximate causation, whereas the second refers to ultimate causation.

Suppose that a group of male pied flycatchers migrated from a region where there were no collared flycatchers to a region where both species were present. Assuming events like this are very rare, which of the following scenarios is LEAST likely?

The frequency of hybrid offspring would decrease.

In the hypothesis that C. stellatus (a species of barnacle) is competitively excluded from the lower intertidal zone by B. balanoides (another species of barnacle), what could be concluded about the two species?

The fundamental and realized niches of B. balanoides are identical, but the fundamental and realized niches of C. stellatus are different.

When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?

The gene involved is on the X chromosome.

Which of the following mechanisms is (are) used to coordinate the expression of multiple, related genes in eukaryotic cells?

The genes share a single common enhancer, which allows appropriate activators to turn on their transcription at the same time.

All three domains (Bacteria, Archaea, and Eukarya) follow the same genetic code. Therefore, which of the following statements would most likely be correct?

The genetic code evolved before the different domains diverged.

Why are seedless vascular plants considered paraphyletic rather than monophyletic?

The group includes their common ancestor but also the seeded descendants of that same ancestor

As N approaches K for a certain population, which of the following is predicted by the logistic equation?

The growth rate will approach zero.

In examining an unknown animal species during its embryonic development, how can you be sure what you are looking at is a protostome and not a deuterostome?

The mouth develops first, and the anus develops later.

In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after she has removed its 5' cap and poly-A tail. Which of the following would you expect her to find?

The molecule is digested by enzymes because it is not protected at the 5' end.

Why can't a female lizard have both high fecundity and high survival?

The more energy the female devotes to offspring, the less that can be devoted to her survival.

Suppose a researcher for a pest-control company developed a chemical that inhibited the development of an embryonic mosquito's endodermal cells. Which of the following would be a likely mechanism by which this pesticide works?

The mosquito would have trouble digesting food, due to impaired gut function.

Which of the following is a feature of the tube-within-a-tube body plan in most animal phyla?

The mouth and anus form the ends of the inner tube.

The following question is based on information from Frank M. Frey, "Opposing Natural Selection from Herbivores and Pathogens May Maintain Floral-Color Variation in Claytonia virginica (Portulacaceae)," Evolution 58(11), 2004: 2426—37. Claytonia virginica is a woodland spring herb with flowers that vary from white to pale pink to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time?

The percentage of pink flowers should increase over time.

Two frog populations (same species) living in two neighboring lakes sing slightly different courtship songs. Increased irrigation makes the land between the two lakes wetter, allowing frogs to expand their ranges to the area between the lakes. Females in both populations prefer loud frogs to quieter frogs but do not distinguish between the two slightly different songs. Assuming that courtship song differences have a genetic basis, predict what will likely happen to the songs of the two frog populations.

The songs will become more similar to each other.

Two researchers experimentally formed tetraploid frogs by fertilizing diploid eggs from Rana porosa brevipoda with diploid sperm from Rana nigromaculata. When they mated these tetraploid frogs with each other, most of the offspring that survived to maturity were tetraploid, with chromosome sets of both diploid parent species. Based on these results, if this type of tetraploid formed in the wild, what would be the result? (Y. Kondo and A. Kashiwagi. 2004. Experimentally induced autotetraploidy and allotetraploidy in two Japanese pond frogs. Journal of Herpetology 38(3):381—92.)

The tetraploids would be reproductively isolated from both parent species.

Sarah noticed the presence of many empty exoskeletons attached to emergent vegetation. These exoskeletons looked exactly like those of the largest of the "mystery organisms" she had seen in the pond. They also looked similar to the bodies of the dragonflies that patrolled the surface of the pond. If Sarah had learned a lot from her college biology class, what should she have concluded about the mysterious pond organisms?

They are larval dragonflies, destined to undergo incomplete metamorphosis.

Which of the following supports the argument that viruses are nonliving?

They are not cellular.

In the following figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus is separated into five depth habitats (1—5), with 1 being the shallowest. Why should deepwater shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

They have been geographically isolated from each other for a longer time.

Basidiomycetes are the only fungal group capable of synthesizing lignin peroxidase. What advantage does this group of fungi have over other fungi because of this capability?

This fungal group can break down the tough lignin, which cannot be harnessed for energy, to get to the more useful cellulose.

In graph (b) in the accompanying figure, which of the following best explains the data given about Lotus corniculatus?

This plant forms multiple AMF associations, growing best with increased fungal diversity.

There is an island in the middle of a large river that houses a large population of ants. Damming of the river causes the island to flood and only the highest points of the island are now above water. The ants cannot swim, so are now in multiple isolated populations. Which of the following best describes this event?

This situation represents isolation by vicariance.

You have isolated a newly discovered virus and are attempting to characterize it. You begin with its genome. You first isolate the virion-producing mRNA from cultured cells infected with the virus. When you compare this mRNA to the viral genome, you find that they are complementary. What does this tell you?

This virus has a negative-sense genome.

How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level predators?

Top-level predators are destined to have small populations that are sparsely distributed.

Which of the following is a consequence of biomagnification?

Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers.

Which of the following statements is TRUE about protein synthesis in prokaryotes?

Translation can begin while transcription is still in progress.

Considering the phylogenetic trees above as strictly hypothetical and applying the principle of parsimony to the trait "ability to fly," which of the two phylogenetic trees shown is better?

Tree 1

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best explains what happened?

Triazine-resistant weeds were more likely to survive and reproduce.

Which of the following is a widely supported explanation for the tendency of tropical communities to have greater species diversity than temperate or polar communities?

Tropical communities are generally older than temperate and polar communities.

Over long periods of time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

Which of the following questions is asked in functional genomics research?

What is the pattern of gene expression during mouse development?

Refer to the study by Poulsen et al. and the accompanying figure. The data graphed in the figure could be an artifact if latrunculin A kills this species of diatoms (that is, that may be why the cells are not moving). Which of the following would be the best evidence that latrunculin A is NOT killing the cells?

When the toxin was washed off the culture, the cells began to move again.

There is a population of beetles that typically have black wings. A scientist studying these beetles knows that their eggs hatch in early spring, the young insects grow through the late spring and summer, they lay eggs in the early fall, and they die in the early winter. Recently some beetles have been born with white wings. Early in life, the black- and white-winged beetles seem to be very similar in number of mating events, eggs laid, and survival rates, but shortly after laying their eggs, the white beetles die and there are only black-winged beetles during the late fall. Which of the following is a TRUE statement about the beetles?

White- and black-winged beetles have equal fitness.

What would happen to the seasons if the Earth were tilted 35 degrees off its orbital plane instead of the usual 23.5 degrees?

Winters and summers would be more severe

What conclusion can you draw from the accompanying figure?

Without direct contact, mussels can sense the presence of crabs.

The following question(s) are based on information in Hopi E. Hoekstra, Kristen E. Drumm, and Michael W. Nachman, "Ecological Genetics of Adaptive Color Polymorphism in Pocket Mice: Geographic Variation in Selected and Neutral Genes," Evolution 58(6), 2004: 1329—41.The accompanying figure shows the distribution of pocket-mouse coat colors in several Arizona populations found either on light-colored granite substrate or on dark volcanic rock (dark substrate). The Melanocortin-1 receptor (Mc1r) alleles, D and d, differ by four amino acids. Mice with DD and Dd genotypes have dark coats, whereas mice with the dd genotype are light colored. What sort of genotype frequencies might you expect to find in the Xmas, Mid, and O'Neill populations?

Xmas-high dd frequency; Mid-high DD frequency, O'Neill-high Dd frequency

Imagine that you are managing a large game ranch. You know from historical accounts that a species of deer used to live there, but they have been extirpated. After doing some research to determine what might be an appropriately sized founding population, you reintroduce them. You then watch the population increase for several generations, and graph the number of individuals (vertical axis) against the number of generations (horizontal axis). With no natural predators impacting the population, the graph will likely appear as ________.

a "J," increasing with each generation

Of the following, which is the most current description of a gene?

a DNA sequence that is expressed to form a functional product: either RNA or polypeptide

You want to engineer a eukaryotic gene into a bacterial colony and have it expressed. What must be included in addition to the coding exons of the gene?

a bacterial promoter sequence

Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?

a base deletion near the start of a gene

Which of the following DNA mutations is most likely to damage the protein it specifies?

a base-pair deletion

Three populations of crickets look very similar, but the males have courtship songs that sound different. What function would this difference in song likely serve if the populations came in contact?

a behavioral reproductive isolating mechanism

Use the following information to answer the question below. In 1983, a population of dark-eyed junco birds became established on the campus of the University of California, San Diego (UCSD), which is located many miles from the junco's normal habitat in the mixed-coniferous temperate forests in the mountains. Juncos have white outer tail feathers that the males display during aggressive interactions and during courtship displays. Males with more white in their tail are more likely to win aggressive interactions, and females prefer to mate with males with more white in their tails. Females have less white in their tails than do males and display it less often. (Pamela J. Yeh. 2004. Rapid evolution of a sexually selected trait following population establishment in a novel habitat. Evolution 58[1]:166—74.) Refer to the paragraph on dark-eyed junco birds. The UCSD campus male junco population tails were, on average, 36 percent white, whereas the tails of males from nearby mountain populations averaged 40—45 percent white. If this observed trait difference were due to a difference in the original colonizing population, it would most likely be due to ________.

a founder effect

An earthquake decimates a ground-squirrel population, killing 98 percent of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake?

a genetic bottleneck

Which of the following best defines a cohort?

a group of individuals from the same age group, from birth until they are all dead

A land snail, a clam, and an octopus all have ________.

a mantle

In a tide pool, a student encounters an organism with a hard outer covering that contains much calcium carbonate, an open circulatory system, and gills. The organism could potentially be a crab, a shrimp, a barnacle, or a bivalve. The presence of which of the following structures would allow for the most certain identification of the organism?

a mantle

Use the following information and figure to answer the question(s) below. Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see the accompanying figure).The figure contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage. One morphological feature of some modern cetaceans is a vestigial pelvic girdle. If it is determined that the cetacean lineage diverged from the artiodactyls' lineage after the divergence of pigs and other artiodactyla, then the vestigial pelvic girdle of cetaceans should be considered a shared ________.

derived character of the cetaceans

The observation that island D. yakuba are more closely related to mainland D. yakuba than island D. yakuba are to D. santomea is best explained by proposing that D. santomea ________

descended from an original colony of D. yakuba, of which there are no surviving members; the current island D. yakuba represent a second colonization event from elsewhere

Which of the following is the best modern definition of evolution?

descent with modification

Which of the following would be LEAST likely in the fossil record?

desert-dwelling species

Which of the following was a challenge to the survival of the first land plants?

desiccation

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should ________.

determine if hair length is heritable

A researcher wants to know if gene flow is contributing to evolution of drought tolerance of pitcher plants in a specific bog. As a control, she should

determine if the population is in Hardy—Weinberg equilibrium.

Researchers have found a new type of bacteria, and they want to determine its phylum. What would be the most reliable method to do so?

determining the ribosomal RNA sequence of the bacteria

A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. We expect that the plants would ________.

develop the typical symptoms of TMV infection

Similar gill pouches in embryos of a chick, human, and cat are an example of ________.

developmental homology

The Isthmus of Panama (a narrow strip of land connecting North and South America) started rising about 10 million years ago. The Pacific and Caribbean oceans were completely separated by the isthmus about 3 million years ago. Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appear to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus, were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs seldom courted each other, and those that did mate seldom produced fertile offspring. (N. Knowlton, L. A. Weigt, L. A. Solorzano, D. K. Mills, and E. Bermingham. 1993. Divergence in proteins, mitochondrial DNA, and reproductive incompatibility across the Isthmus of Panama. Science 260:1629—32.) There are currently two large, permanent bridges that span the Panama Canal. The bridges are about eight miles apart. If snapping shrimp avoid swimming at night and avoid swimming under shadows, then what do these bridges represent for the snapping shrimp?

geographic barriers

Which of the following can be effective in preventing the onset of viral infection in humans?

getting vaccinated

A farm pond, usually dry during winter, has plenty of water and aquatic pond life during the summer. One summer, Sarah returns to the family farm from college. Observing the pond, she is fascinated by some six-legged organisms that can crawl about on submerged surfaces or, when disturbed, seemingly "jet" through the water. Watching further, she is able to conclude that the "mystery organisms" are ambush predators, and their prey includes everything from insects to small fish and tadpoles. Sarah observed that the mystery pond organisms never come up to the pond's surface. If she catches one of these organisms and observes closely, perhaps dissecting the organism, she should find ________.

gills

Flycatcher birds that migrate from Africa to Europe feed their nestlings a diet that is almost exclusively moth caterpillars. The graph shows the mean dates of arrival, bird hatching, and peak caterpillar season for the years 1980 and 2000. The shift in the peak of caterpillar season is most likely due to ________.

global warming

We derive measures for assessing the value of an individual habitat fragment for the dynamics and persistence of a metapopulation living in a network of many fragments. We demonstrate that the most appropriate measure of fragment value depends on the question asked. Specifically, we analyze four alternative measures: the contribution of a fragment to the metapopulation capacity of the network, to the equilibrium metapopulation size, to the expected time to metapopulation extinction and the long-term contribution of a fragment to colonization events in the network. The latter measure is comparable to density-dependent measures in general matrix population theory, though some differences are introduced by the fact that "density dependence" is spatially localized in the metapopulation context. We show that the value of a fragment depends not only on the properties of the landscape but also on the properties of the species. Most importantly, variation in fragment values between the habitat fragments is greatest in the case of rare species that occur close to the extinction threshold, as these species are likely to be restricted to the most favorable parts of the landscape. We expect that the measures of habitat fragment described and analyzed here have applications in landscape ecology and in conservation biology. Copyright © 2003 Elsevier Inc. All rights reserved. (Otso Ovaskainen and Ilkka Hanski. 2003. How much does an individual habitat fragment contribute to metapopulation dynamics and persistence? Theoretical Population Biology 64:481—95.) One measure for the value of the patch was given by the long-term contribution of a fragment to colonization events in the network. How do the properties of a landscape and the properties of a species affect the value of a patch? The value of the fragment depends ________.

on the properties of the landscape and the properties of the species

E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?

one low-density and one intermediate-density band

Semiconservative replication involves a template. What is the template?

one strand of the DNA molecule

Use the following information to answer the question below. About 3 million years ago, the Isthmus of Panama (a narrow strip of land connecting North and South America) formed, dividing marine organisms into Pacific and Caribbean populations. Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appeared to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs were not very interested in courting with each other, and any that did mate almost never produced fertile offspring. (N. Knowlton, L. A. Weigt, L. A. Solorzano, D. K. Mills, and E. Bermingham. 1993. Divergence in proteins, mitochondrial DNA, and reproductive incompatibility across the Isthmus of Panama. Science 260:1629—32.) Refer to the paragraph about the formation of the Isthmus of Panama. The sister populations on opposite sides of the isthmus are true species under which species concept?

the morphological species, biological species, and phylogenetic species concepts

The comparison between the number of human genes and those of other animal species has led to many conclusions, including that ________.

the number of proteins expressed by the human genome is far more than the number of its genes

There should be a strong positive correlation between the rate of protein synthesis and ________.

the number of ribosomes

When comparing the genomes of a bacterial parasite versus a free-living, nonparasitic bacterium, one expects to find that ________.

the parasite will have a smaller genome

Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This ratio suggests that ________.

the parents were both heterozygous for the particular trait

Trophic efficiency is ________.

the percentage of production transferred from one trophic level to the next