BIO EXAM 4

All species of humans other than Homo sapiens became extinct:

between 30,000 and 12,000 years ago. (Neandertals became extinct about 30,000 years ago, H. erectus about 27,000 years ago, and H. floresiensis about 12,000 years ago.)

What characteristics define a chordate?

bilateral symmetry, defined tissues, and gut develops from back to front (All chordates exhibit bilateral symmetry, have defined tissues, and have a gut that develops from back to front.)

What characteristics define an arthropod?

bilateral symmetry, gut develops from front to back, and grows by molting (All arthropods possess bilateral symmetry, they are protostomes, and they grow by shedding their exoskeleton.)

Which species concept is based on the degree of reproductive isolation between populations of species?

biological species concept

All cnidarians have tentacles that are armed with rows of stinging:

cnidocytes. (Cnidocytes are stinging cells that cnidarians use to capture prey.)

What were the primary lines of evidence demonstrating the occurrence of evolution?

-fossil record -biogeography -comparative anatomy and embryology -molecular biology

Sponges are:

-hermaphrodites -asexual -sessile -members of phylum Porifera

The three phenomena that tend to trigger adaptive radiations are:

-mass extinctions -colonization events -evolutionary innovations

What is the cause of background extinction?

-natural selection -competition -changing environmental conditions -bad luck

What are common features among bacteria?

-single-celled -no nucleus or organelles -circular DNA molecule(s) -asexual

Charles Darwin initially sketched out his ideas about evolution by natural selection in 1842; however, he didn't actually publish a full book, detailing his ideas, until:

1859. (Darwin waited nearly 16 years to publish his ideas. It was only after biologist Alfred Russel Wallace contacted him in 1858 with his own description of evolution by natural selection that Darwin sprang into action and finally wrote and published his book, The Origin of Species.)

In what decade did Stanley Miller and Harold Urey conduct their famous experiment?

1950s (The Urey-Miller experiment took place in 1953.)

What role do analogous traits play in constructing phylogenies?

Analogous traits do not play a role in constructing phylogenies. (When different organisms live in similar environments with similar selective forces, traits may arise that are similar (analogous traits); however, these traits do not indicate that the two species are closely related.)

You find a protostome that has a closed circulatory system and a segmented body. In which phylum does it most likely belong?

Annelida (Annelids, or segmented worms, have segmented bodies. Also, unlike flatworms, which have no specialized circulatory organs, annelids have a closed circulatory system.)

Which scientist is incorrectly matched to his scientific/evolutionary contribution? A) Georges Buffon showed that earth is much older than previously believed. B) Georges Cuvier showed through genetic experiments that extinction had occurred. C) Jean-Baptiste Lamarck suggested that living species might change over time. D) Charles Lyell theorized that geological forces had shaped the earth and continue to do so.

B) Georges Cuvier showed through genetic experiments that extinction had occurred. (Through documentation of fossil discoveries (not genetic experiments), Georges Cuvier demonstrated extinction had occurred.)

Which of the following species of humans never migrated out of Africa? A) Homo sapiens B) Homo ergaster C) Homo neanderthalensis D) Homo erectus E) Homo floresiensis

B) Homo ergaster (Homo ergaster did not migrate out of Africa, unlike Homo erectus, which spread across eastern Europe and Asia.)

Which of the following about insects is false? A) Insects have a tough exoskeleton that acts like body armor. B) All insects are arthropods. C) Wings and the ability to fly first appeared in insects. D) All insects have three life stages: larva, pupa, and adult. E) The primary role of an adult insect is to reproduce.

D) All insects have three life stages: larva, pupa, and adult. (Not all insects go through three distinct life stages; about 83% of insect species do. Some insects, like grasshoppers, only have two stages, nymph and adult, which is known as incomplete metamorphosis.)

Which of the following is not an important reason that natural selection does not lead to perfect organisms? A) Environments change quickly; natural selection may be too slow to adapt an organism in a population to the constantly "moving target" of the environment. B) Variation is created by random processes and natural selection can only "work" with the variations that show up. C) There are often multiple alleles for a trait; each allele may represent an equally fit "solution" to the challenges of the environment. D) All of the above are important reasons that natural selection does not lead to perfect organisms. E) None of the above is an important reason explaining why natural selection does not lead to perfect organisms.

D) All of the above are important reasons that natural selection does not lead to perfect organisms. (When Charles Darwin wrote that species "tend to progress towards perfection," he failed to acknowledge the factors listed here, which essentially prevent "perfect" organisms.)

As mammals evolved, there was a gradual transition from bodies with short legs to bodies with longer legs, held vertically beneath the trunk of the animal. Which of the following was a result of this anatomical change in early mammals? A) Less heat was generated from the body. B) Cellular respiration rates decreased. C) Heat was able to be released from under the body. D) The animals could run faster after prey. E) The animals were able to produce milk.

D) The animals could run faster after prey. (Evolution of longer legs allows mammals to run faster.)

Which of the following is an indisputable component of the origin of life on earth? A) Urey and Miller replicated the exact atmosphere of early earth in their experiment. B) Metals in the atmosphere were able to act as a catalyst to spark cellular metabolism. C) Life originated elsewhere in the universe and traveled to earth. D) The first living cells contained no nucleus, no organelles, and a circular strand of genetic information. E) The first self-replicating molecule was definitely RNA.

D) The first living cells contained no nucleus, no organelles, and a circular strand of genetic information.

Archaeans share a common ancestor with:

eukaryotes (Even though archaea physically resemble bacteria, they are more closely related to eukarya, exhibiting similar cell membranes, ribosomes, and similar enzymes.)

Which term below is the best match for the following statement: "Natural selection can act on different anatomical starting material to produce modifications that serve similar purposes"? A) genetic drift B) fitness C) divergent evolution D) convergent evolution E) homologous structures

D) convergent evolution (Analogous structures with similar functions that arise from different starting anatomy are produced through convergent evolution.)

Which of the following is not an important feature in distinguishing animals from each other? A) presence and cellular arrangement of tissues B) development of the gut C) growth of skeletal elements D) method of locomotion (movement) E) body symmetry

D) method of locomotion (movement) (This is not a common feature used to separate animal groups.)

Protists are all alike in that they all are:

eukaryotic. (They are a very diverse group, and the presence of a nucleus is one of the few characteristics they share.)

____________ selection favors organisms that have character values at both extremes of the phenotypic distribution.

Disruptive

Which of the following is not a feature of archaea? A) They have some enzymes similar to those found in eukaryotes. B) They have cell membranes. C) Their cell walls contain polysaccharides that are unique among the three domains. D) They have ribosomes. E) They have a nucleus.

E) They have a nucleus.

Based on the information given, which of the organisms described below most likely has the LOWEST fitness? A) a sand-colored mouse living at the beach B) a human who dies at age 40 who has had four children C) a short-lived rabbit with a greater than average number of offspring, relative to other individuals in its population D) a dark-colored mouse living in the brown brush E) a sterile organism that lives twice as long as the average longevity in its population

E) a sterile organism that lives twice as long as the average longevity in its population (An organism that is sterile will not be reproductively successful and thus will have low fitness.)

Birds are grouped with turtles, lizards, snakes, alligators, and crocodiles. Birds, however, have feathers and can generate their own body heat, which other reptiles cannot do. Which of the following likely explains the original evolutionary function of feathers in early reptiles? A) structural support B) locomotion C) insulation D) flight E) behavioral displays

E) behavioral displays (The original function of feathers in early reptiles most likely was courtship behavior.)

What do we know about evolution?

Evolution is occurring continuously in wild and controlled populations.

What statement about evolution is true?

Evolution undeniably occurs.

_________________ can complicate attempts to determine phylogenies based on sequence data.

Horizontal gene transfer (Bacteria can transfer DNA directly to an unrelated species, which can complicate the process of assessing evolutionary relatedness by genotyping.)

Why do human embryos have gill pouches?

Humans and fishes share a common ancestor. (Shared embryological features such as gill pouches indicate that organisms shared a common ancestor.)

What is true of reptiles but not amphibians?

Reptiles have amniotic eggs, whereas amphibians do not. (As a result, amphibians must lay their eggs in water, while reptiles lay their eggs on land.)

While on the HMS Beagle, Darwin was intrigued by glyptodonts because:

glyptodont fossils resembled a species that currently existed but were much, much larger. (Glyptodont fossils resembled armadillos, which are extant. However, the glyptodont fossils were significantly larger.)

Stinky "morning breath" is caused by:

accumulation of sulfur-containing waste products from anaerobic bacteria. (It is the increase in metabolic activity and number of anaerobic bacteria that cause "morning breath.")

The most primitive group of animals that had lungs were the:

amphibians. (They have primitive lungs and were important to the transition to land.)

A population:

is a group of organisms of the same species living in the same geographic region. (This includes natural habitats as well as unnatural habitats, such as a laboratory setting.)

Background extinctions occur mostly due to:

natural selection

In complex chordates, such as vertebrates, the ____________ is eventually replaced by a vertebral column.

notochord (In more complex chordates, the notochord in early embryos is replaced by a vertebral column, or backbone, as the embryo develops.)

Three major distinguishing features of the primates are that they have binocular vision, arms that can rotate in their sockets, and:

opposable thumbs

The fact that RNA can catalyze reactions necessary for replication gave rise to:

the RNA world hypothesis. (This hypothesis proposes that the world may have been filled with RNA-based life before it was filled with DNA-based life, as we see today.)

All northern elephant seals come from a very small genetic pool. This is because in the 1890s a large number of them were very quickly killed until their population size was reduced to only about 20 individuals. Though their population has since increased to over 30,000 individuals, all their genes have come from those 20 individuals. What population genetic concepts does this example represent?

the bottleneck effect (The bottleneck effect occurs when a large part of a population dies and the survivors establish a new population.)

In terms of evolutionary trees, what exactly is a node?

the point at which two groups diverge on an evolutionary tree (The evolutionary tree will branch at this point, indicating that the two species have diverged.)

The chief concern among conservation biologists trying to protect small populations is:

to preserve genetic diversity. (Genetic drift is most likely to occur in small populations. The death of only a few individuals could result in the loss of alleles from a population.)

Urey and Miller's experimental setup was able to produce all twenty of the amino acids found in proteins. Some amino acids contain the element oxygen. Which starting material in the Urey-Miller experiment was the source of this element?

water

Why can radioactive carbon be used by scientists to date the ages of ancient fossilized organisms?

-Carbon components are found in all of the earth's creatures. -Radioactive carbon is produced in the atmosphere at the same rate as the radioactive carbon decays. -After an organism dies, its radioactive carbon concentration decreases while the concentration of nonradioactive carbon stays the same. -The rate of decay for radioactive carbon always remains the same.

What statements about fitness are true?

-Fitness is the relative success of a phenotype or genotype in a population. -Fitness depends on the environment in which an organism lives. -Fitness depends on an organism's reproductive success compared with others in the population.

It is said that the fossil record is an incomplete record. Why is that?

-The soft parts of an organism almost always decay rapidly and completely after death. -Only a few environments demonstrate reduced forces of decomposition resulting in the preservation of the organism's hard parts (i.e., teeth, bones).

An organism's fitness is measured:

-relative to other genotypes/phenotypes in the population. -only for a specific environment. -by reproductive success. -for a given point in time.

Estimates of evolutionary relatedness based on a "molecular clock" are supported by:

-the fossil record. -observations of comparative anatomy.

Terrestrial vertebrates are descendants of lobe-finned fishes that lived during the Devonian period, approximately:

400 million years ago. (The Devonian period took place about 400 million years ago. Terrestrial vertebrates' ancestors, the lobe-finned fishes, lived during this time.)

Animals without backbones represent more than ______ of the total species in the animal kingdom.

95% (Invertebrates are the largest and most diverse group on animals.)

Birds are a branch of the reptile lineage but, unlike other reptiles, birds are able to do which of the following? A) generate body heat B) produce amniotic eggs C) control their body temperature using external heat D) produce milk for their young E) have multiple offspring at the same time

A) generate body heat (Birds are endotherms, meaning they are able to generate body heat via cellular respiration. Other reptiles, however, are ectotherms, meaning they must bask in the sun to raise their body temperature.)

Which of the following is incorrectly matched? A) molecular biology: examination of life at the level of atoms and compounds B) fossil record: physical evidence of organisms from the past C) biogeography: patterns in geographic distribution of organisms D) comparative anatomy: growth, development, and body structures of major groups of organisms E) laboratory and field studies: implementation of the scientific method to observe and study evolution

A) molecular biology: an examination of life at the level of atoms and compounds (Molecular biology deals with individual molecules, especially DNA.)

________________ is defined as a rapid diversification event that occurs when, in a brief period of time, a small number of species diversify into a much larger number of species that are able to live in a wide diversity of habitats.

Adaptive radiation (Adaptive radiation occurs when there is a large rapid diversification of species.)

Which of the following is true of all animals? A) They have sense organs, like eyes and ears. B) They are capable of movement at some stage of their life cycle. C) They reproduce asexually. D) They can sustain themselves exclusively by photosynthesis. E) They are made up of single and multicellular individuals.

B) They are capable of movement at some stage of their life cycle. (In addition to movement, all animals are characterized by multicellularity and inability to make their own food, meaning they must eat other organisms.)

Cephalopods include all of the following kinds of animals except: A) nautiluses. B) clams. C) All of these organisms are cephalopods. D) octopuses. E) squid.

B) clams. (Clams are bivalve mollusks with a soft body, protected by a pair of hard shells that are hinged together by a ligament.)

Which of the following lists of groupings or taxons is in descending order, from most inclusive to least inclusive? Some lists may be missing some of the intermediate taxons. A) family, order, class, species, genus B) kingdom, class, family, genus, species C) phylum, class, order, genus, family D) domain, phylum, family, class, species E) class, family, species, order, phylum

B) kingdom, class, family, genus, species

The three domains of life are:

Bacteria, Archaea, Eukarya

Artificial selection and natural selection are similar in what way?

Both artificial selection and natural selection result in a change in allele frequencies over time. (Both types of selection are means of evolution.)

Which of the following statements correctly distinguishes between microevolution and macroevolution? A) Macroevolution is limited to changes in allele frequencies without speciation. B) Microevolution occurs in a fundamentally different process than macroevolution. C) Macroevolution includes speciation, while microevolution does not. D) Macroevolution occurs faster than microevolution. E) Macroevolution can lead to microevolution after a long period of time.

C) Macroevolution includes speciation, while microevolution does not. (Whereas microevolution is marked by slight changes in allele frequencies over one or a few generations, macroevolution is the accumulated effect of microevolution over time, including diversification of species.)

Which statement about radiometric dating is false? A) Radiometric dating allows scientists to learn the ages and chronologies of fossils found in rocks. B) Radiometric dating is achieved by measuring the relative amounts of radioactive isotopes present in rock and their leftover decay products C) Radiometric dating only provides enough information to know the relative ages of rocks and not their absolute numerical ages. D) Radiometric dating has allowed scientists to determine the age of the earth and living organisms on it. E) Radiometric dating is possible because radioactive isotopes in rock break down at a constant rate.

C) Radiometric dating only provides enough information to know the relative ages of rocks and not their absolute numerical ages. (Radiometric dating makes it possible to determine the absolute ages of rocks.)

If a population is in Hardy-Weinberg equilibrium, which of the following is true? A) More homozygotes are dying. B) More recessive alleles are being eliminated from the population. C) Recessive and dominant alleles are not changing in frequency over time. D) Evolution is occurring. E) Non-random mating is occurring in the population.

C) Recessive and dominant alleles are not changing in frequency over time. (The allele frequencies do not change in a population in Hardy-Weinberg equilibrium.)

Which statement about bacteria is false? A) They are single-celled B) They reproduce asexually. C) They have organelles. D) They are prokaryotic. E) They have circular DNA.

C) They have organelles.

Terrestrial vertebrates are classified either as amniotes or non-amniotes. Which of the following animals is a non-amniote? A) birds B) humans C) amphibians D) mammals E) reptiles

C) amphibians (Amphibians lack desiccation-proof amniotic eggs. As a result, they must reproduce in water.)

Which of the following insect orders has the most species currently named by scientists? A) butterflies and moths B) flies C) beetles D) grasshoppers and crickets E) bees, wasps, ants, and sawflies

C) beetles (More than 25% of all described species on earth are beetles.)

Nearly one-third of amphibian populations are facing extinction. Which of the following does not attribute to the universal decline in amphibian populations? A) habitat destruction B) fungal disease C) competition from mammals D) pollution E) climate change

C) competition from mammals (Competition is a common part of life in a community and is not a factor contributing to amphibian decline.)

Which of the following characteristics is common to all mammals? A) viviparity B) teeth C) mammary glands D) land-dwelling E) bipedal

C) mammary glands (All mammals share two common characteristics: mammary glands and hair.)

Which one of the common names are matched correctly with its phyla? A) roundworms: Annelida B) tapeworms: Nematoda C) roundworms: Nematoda D) flatworms: Annelida E) segmented worms: Platyhelminthes

C) roundworms: Nematoda (This is a large group of roundworms with no segmentation.)

Which of the following is an animal with rigid bones, jaws, and a swim bladder? A) hagfish B) lobe-finned fish C) salmon D) sharks E) lampreys

C) salmon

Which of the following is an example of an echinoderm? A) crab B) centipede C) sand dollar D) ant E) frog

C) sand dollar (They have radial symmetry, small tube feet for movement, and a spiny outer covering--all of which are characteristics of echinoderms.)

Which animal is an ectotherm? A) hawk B) sea lion C) snake D) human E) dolphin

C) snake (Snakes are exothermic, meaning their body temperature is controlled by external conditions, such as air temperature.)

Which of the following is not a characteristic of tunicates? A) free-swimming larvae B) pharyngeal slits C) vertebrae D) deuterostome E) filter-feeders

C) vertebrae (Tunicates are a member of the chordate phylum that do not possess vertebrae.)

Which of the following work by earlier scientists was least important for Darwin's development of the theory of evolution by natural selection? A) Buffon's discovery that the world was much older than previously thought B) Cuvier's discovery that there were species of animals that once lived on the earth that no longer live on the earth C) Lamarck's suggestion that species change over time D) Wallace's discovery of distinct bioregions in the Malaysian archipelago E) Lyell's argument that geological forces have continuously changed the features of the earth

D) Wallace's discovery of distinct bioregions in the Malaysian archipelago (Darwin's development of the theory of evolution was independent of Wallace's work.)

Which of the following correctly pairs a stage of arthropod metamorphosis with its most significant change at that stage? A) pupa: the pupa eats and grows large enough to become an adult B) adult: changes occur throughout the entire adult life until reproduction C) zygota: the sperm and the egg unite D) pupa: body structures of the larva are broken down and reassembled E) larva: embryological growth and change occurs at this stage

D) pupa: body structures of the larva are broken down and reassembled (This is the actual defining stage of metamorphosis when the larva encloses itself in a case, body structures are broken down, and new structures are assembled into adult form.)

Which of the following does not cause mutation? A) chance B) the complex process of cell division C) environmental influences D) social influences E) chemical influences

D) social influences

Which of the following organisms is not a chordate? A) tunicate B) reptile C) lancelet D) starfish E) stingray

D) starfish (A starfish is not a chordate; it is found in the echinoderm phylum.)

Which of the following are examples of experiments involving evolution? A) fruit flies selected for starvation resistance B) rabbits selected for increased speed C) bacteria that have developed resistance to antibiotics D) dogs bred for smaller body size E) All of the above.

E) All of the above. (Evolution can be observed in a wide range of experiments that include both laboratory and natural environments.)

Cnidarians are a unique group of organisms. Which of the following statements about cnidarians is true? A) They have a specialized sensory organ known as a cnidocyte. B) Cnidarians include jellyfish, sea urchins, and corals. C) Cnidarians are omnivores. D) Cnidarians get their name from their body shape. E) Cnidarians can be sessile (polyp) or free-floating (medusa).

E) Cnidarians can be sessile (polyp) or free-floating (medusa). (These are the two body types of cnidarians.)

Which of the following is an advantage of radial symmetry? A) movement with equal ease in any direction B) sense organs distributed around their circumference C) even distribution of appendages D) sense organs grouped at the front end of the body, opposite the side of locomotion E) The first three choices are all advantages of radial symmetry.

E) The first three choices are all advantages of radial symmetry.

Which of the following best explains why bacteria have the greatest biomass of any other plant or animal on earth? A) Bacteria are able to live essentially anywhere—soil, air, water, ice, etc. B) Some bacteria can make their own food. C) Some bacteria can survive and thrive with or without oxygen. D) There is one dominant species of bacteria that has a greater molecular weight than all other bacteria, accounting for the high biomass. E) The first three choices are correct.

E) The first three choices are correct. (Metabolically, they are very diverse, with many more species to discover.)

A new animal is discovered with a prominent muscular foot that attaches to underwater rocks. The animal also has a one-piece shell. To which of the following animal groups does this new animal belong? A) bivalves B) cephalopods C) echinoderms D) crustaceans E) gastropods

E) gastropods (This is the largest group of mollusks and includes both terrestrial and aquatic organisms.)

Which of the following pairs of organisms is probably monophyletic? A) dolphins, sharks B) giant sequoia trees, magnolia trees C) archaeans, bacteria D) plants, fungi E) large cactus finch, vampire finch

E) large cactus finch, vampire finch (Both types of finches share a recent common ancestor and are monophyletic.)

Which of these animals is not an arachnid? A) scorpion B) mite C) spider D) tick E) shrimp

E) shrimp (Shrimp are crustaceans. Unlike arachnids, which are land-dwelling arthropods, most crustaceans are aquatic.)

What is the relationship between coral and zooxanthellae?

Mutually symbiotic; zooxanthellae provide the coral with nutrition, while the coral provide zooxanthellae with carbon dioxide. (Both of these organisms depend on each other for survival.)

In a large population of randomly breeding foxes, a dominant allele results in a soft, brown pelt, while a recessive allele results in a rough, grey pelt. The dominant allele is found in 80% of the population while the recessive allele is found in 20%. There is no migration, drift, or selection in the population. When human beings enter this habitat, they selectively hunt foxes with brown pelts. After many generations of this activity, how will this population change?

The frequency of the recessive allele will rise above 20%, while the dominant allele will decrease below 80%. (This will result since hunters are removing these alleles and making them less frequent over time.)

During genetic drift, where do the genes drift to?

The genes do not drift at all—drift is a mathematical metaphor that means gene frequencies are unstable and drift from one number to another. (Genetic drift is metaphorical. Genetic drift causes evolution when an allele's frequency changes by chance and not for reasons related to an allele's influence on reproductive success.)

During gene flow, where do the genes flow to?

The genes flow into and out of the population due to migration of individuals from one population to another. (This can result in a very fast change in allele frequency of a population and can help a population maintain or increase the gene pool of a population. Gene flow plays an important consideration in animal conservation.)

Which of the following is true about eukarya? A) The majority of the named species on earth are eukarya, and the majority of eukaryotes are insects. B) All of the kingdoms of eukarya can be seen with the naked eye. C) Archaea and eukarya split about 35 billion years ago. D) At the time of the split between eukarya and archaea, eukarya were single-celled, primitive forms of bacteria. E) The majority of all species inhabiting the earth are eukaryotic, and the majority of eukaryotes are insects.

The majority of the named species on earth are eukarya, and the majority of eukaryotes are insects. (However, it's important to note that there are more prokaryotes than there are eukaryotes. Eukaryotes are easier to see in most cases, whereas all prokaryotes are microscopic and not always visible to the naked eye.)

What makes eukaryotes unique?

They have organelles.

The oldest fossilized cells are approximately 3.4 billion years old. As precursors to modern prokaryotes, what was true about these cells?

They lacked a nucleus and organelles. (These ancestors to modern day bacterial cells lacked a nucleus and organelles.)

Which of the following is not true about Neandertals? A) They lived in organized social groups. B) They were more muscular and robust than modern humans. C) They hunted large game with short spears. D) They were nearly the same size as modern humans. E) They lived primarily in Africa

They lived primarily in Africa. (Neandertals lived primarily across Europe and the Middle East.)

Which of the following best supports the idea that the frequency of recessive alleles does not decrease over time?

Using Hardy-Weinberg equilibrium, it can be demonstrated that X allele frequencies will always produce the same genotype frequencies, retaining the allele frequencies. (The kangaroo rat example in Section 10.10 demonstrates this nicely.)

Which statement about vestigial structures is false? A) Vestigial structures exist because they had value in an ancestor species. B) Vestigial structures are a type of homologous structure. C) Vestigial structures are evolutionary leftovers with little or no remaining function. D) Vestigial structures occur in humans. E) Vestigial structures arise through convergent evolution.

Vestigial structures arise through convergent evolution. (Vestigial structures are not a result of convergent evolution; they arise from homologous structures.)

Many people question whether or not viruses are alive. What is the main piece of evidence supporting the idea that they are not alive?

Viruses can only have metabolic activity by taking over the metabolism of other organisms. (In the absence of other organisms, viruses have no metabolic activity of their own.)

The consistent accumulation of mutations that creates differences in the DNA sequences of two diverging groups of organisms is referred to as:

a "molecular clock." (The molecular clock "ticks" over time, and the longer two species have been evolving on their own, the greater the number of changes in amino acid sequences or "ticks of the clock.")

A speciation event is:

a point in evolutionary history where a population splits into independent evolutionary lineages. (This results in the development of different species.)

Charles Darwin spent time on the Beagle:

after graduating from college, while serving as the companion to the captain on the surveying ship. (Charles Darwin's time serving as the companion to the captain on the Beagle occurred after he graduated with his theology degree.)

Experiments in the selection of fruit flies for starvation resistance:

are testable and reproducible. (The fruit fly starvation experiment is a simple way to test a hypothesis about the effect of a treatment on a population, and the results are consistent upon repetition.)

Centuries ago, a breeder chose the smallest variations of poodles to produce the toy poodles we know today. This is an example of:

artificial selection. (Artificial selection is when a trait, chosen by a breeder, is amplified in a short amount of time by choosing parents that possess the most extreme variation of a desired trait.)

Fossils:

can show evidence of evolutionary change by revealing what organisms looked like a long time ago.

The development of jaws allowed fishes to:

capture and kill prey. (Jaws lined with sharp teeth allowed fishes to seize and chew prey. Before the development of jaws, aquatic vertebrates were either gained nutrients by filter feeding or attaching an oral disk to prey.)

A group of birds fly off the mainland and end up on a distant set of islands. Once there, they find a large number of opportunities for diversification and adaptation. This situation is best described as:

colonization event (The situation described above is a colonization event that allowed for selection of different alleles better suited for the different environments.)

In 1954, William Thompson performed a maze-running experiment using rats in which he was able to produce populations of fast maze-learners and slow maze-learners. The results of this experiment indicate that:

complex traits, such as behavior, are heritable. (In short, natural selection can produce and alter complex traits, including behaviors such as the ability of rats to learn and navigate mazes.)

Crabs, lobsters, and barnacles all belong to which group?

crustaceans

The amino acid chains making up hemoglobin in different species:

differ depending on how long it has been since the species last shared a common ancestor. (For example, in humans and rhesus monkeys, there are 146 amino acids that make up the beta chain of hemoglobin; of these, 138 are shared. But between lampreys and humans, only 21 are shared. Lampreys and humans are more distant relatives than humans and monkeys.)

Which organisms are considered deuterostomes?

echinoderms (Echinoderms and chordates are the only two animal groups in which the gut forms back to front.)

If _______ has occurred, the allele frequencies in a population have changed.

evolution (Evolution by definition means that the allele frequencies in a population change over time.)

All species are either ____________ or ______________.

extant; extinct (From an evolutionary perspective, species either exist or no longer exist.)

The taxonomic rank that includes genera but not orders is:

family. (Both genus and species are included in the family taxonomic rank, whereas order is not.)

Feathers are to birds as __________ is/are to _______________.

fur, mammals (Mammals have fur, just as birds have feathers.)

The gray wolf is more closely related to the ________________ than it is to the Tasmanian wolf.

giant anteater (The gray wolf and giant anteater are both placental mammals whereas the Tasmanian wolf is a marsupial.)

In their experiment, what were Urey and Miller attempting to demonstrate about earth's early environment?

how complex organic molecules could have arisen (By creating an environment similar to that of early earth, they were trying to create molecules that would lead to the biological molecules necessary for all life.)

The amount of time that has passed since two species last shared a common ancestor:

is revealed by the degree of similarity in sections of their DNA. (Molecular biology techniques, such as DNA sequencing, reveal the degree of similarity in sections of two species' DNA. In turn, this allows a scientist to estimate the time that has passed since the two species last shared a common ancestor.)

What is not necessary for the evolution of a trait by natural selection?

large population size Only three things are necessary for evolution of a trait by natural selection: 1) variation for a trait 2) heritability 3) differential reproductive success.

Punctuated equilibrium is a model of evolution in which:

long periods of relatively little evolutionary change are interrupted by bursts of rapid change. (The punctuated equilibrium model of evolution involves long periods of very little change punctuated by short periods of rapid change.)

An air environment, gravity, and desiccation are three challenges that were addressed in the evolution of reptiles. What three evolutionary innovations addressed these challenges?

lungs, better limb support, and the amniotic egg (Fins were modified into limbs. Vertebrae were modified to transmit body weight through the limbs to the ground. The site of gas exchange was transferred from gills and swim bladders to lungs. Finally, terrestrial vertebrate eggs with membranes and a shell resisted drying out.)

Radiometric dating:

makes it possible to determine the absolute age of fossils. (This is an important tool that has furthered our knowledge of the earth as well as an ever-increasing volume of fossil evidence.)

Consider a population of 5,000 garter snakes. Two hundred of those snakes split off from the population to a new habitat. When the original population dropped from 5,000 to 4,800, the allele frequencies of various genes changed. The evolutionary process that caused the change in allele frequencies in the original population is:

migration. (This example illustrates the mechanism of migration when a subpopulation leaves and establishes a new population in a different location.)

In dry years in the Galápagos Islands, finches had to eat large, hard seeds. In wet years, however, finches could eat smaller, soft seeds. The alternation between dry and wet years in the habitat of these Galápagos finches illustrates that:

natural selection does not march simply toward an optimized endpoint. (Natural selection acts upon organisms that have advantageous traits in particular environments; if the environment changes, that trait may not be advantageous or even may become disadvantageous.)

Trichinella worms sometimes cause the disease known as trichinosis in humans when undercooked pork is eaten. These organisms have long cylindrical bodies but no segmentation. This species is most similar to which of the following animals? A) Portuguese man-o'-war B) jellyfish C) flatworms D) earthworms E) nematodes

nematodes (These worms are not segmented and have a cylindrical shaped body.)

To establish that evolution by natural selection is operating in a population, one must demonstrate variability for a trait, heritability of that trait, differential reproductive success based on that trait, and:

nothing else. (The absence of any of these will present an obstacle to natural selection.)

While on the voyage of the HMS Beagle, Darwin:

nurtured his love of studying nature, exploring plant and animal diversity, and collecting fossils. (He took every opportunity to explore, describe, and collect as many species of plants, animals, and fossils as possible.)

Which characteristic is unique to lobe-finned fish?

pelvic and pectoral fins (The fins, located on the underside of the body, are unique to lobe-finned fishes.)

The taxonomic rank that includes classes but not domains is:

phylum. (Phylum includes classes but not domains.)

Marsupials are thought to be most closely related to:

placental mammals (Marsupials in Australia have evolved to fill many of the niches that are filled by mammals in other regions of the world.)

The appropriate unit for defining and measuring genetic variation is the:

population. (Changes in the allele frequencies (genetic composition) of a population changes over time as evolution occurs.)

In the fruit fly starvation experiment, the 20% of flies that survived the longest without food in each generation:

possessed heritable alleles that allowed them to survive the longest without food. (Because only the most starvation-resistant flies survived to lay eggs, they were able to pass the heritable trait of starvation resistance on to each subsequent generation.)

Tiktaalik appears to:

represent a transitional species, somewhere between fish and land animals. (It is called a missing link and shows how animals made their way to life on land.)

Which groups of animals grow by molting?

roundworms and arthropods

Which is the only animal phylum to not possess true tissues? A) sponges B) chordates C) flatworms D) mollusks E) cnidarians

sponges (Sponges do not have specialized cells that work together as tissues.)

Exceptionally large babies increase a mother's mortality risk when giving birth, and exceptionally small babies tend to die at birth or shortly afterward. For these reasons, birth weight in human babies is generally:

subject to stabilizing selection. (Birth weight in humans has low variation. The mean stays approximately the same.)

Evolution can occur when certain individuals in a population are born with characteristics that make them more likely to:

survive and reproduce compared to other individuals in the population. (The process of evolution is driven by genetic changes in a population that increase the odds of survival and reproduction.)

The five groups of archaea are:

thermophilic, halophilic, high- and low-pH tolerant, high-pressure tolerant, and methanogenic. (They are divided into groups according to the environment in which they have evolved to live.)

Sponges are sessile organisms as adults. They are classified as animals because:

they exhibit movement as juveniles. (Movement (at some point in an organism's life cycle) is one of the defining characteristics of animals.)

The difference between macroevolution and microevolution is that:

they take place on different time scales. (The origin of entirely new species occurs during macroevolution, and changes in individual traits occur during microevolution.)