ch 20,21,22,23

c

A hybrid zone is properly defined as a) a zone that features a gradual change in species composition where two neighboring ecosystems border each other. b) a zone that includes the intermediate portion of a cline. c) an area where mating occurs between members of two closely related species, producing viable offspring. d) an area where members of two closely related species intermingle, but experience no gene flow. e) an area where two closely related species' ranges overlap.

e

A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of a) fungi and animals. b)mosses and ferns. c)sharks and dolphins. d)archaeans and bacteria. e)chimpanzees and humans.

b

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 a) though we may not consider the fit between the current skeletal arrangements and their functions excellent, we should not doubt that natural selection ultimately produces the best design. b) natural selection is generally limited to modifying structures that were present in previous generations and in previous species. c) natural selection has not had sufficient time to create the optimal design in each case, but will do so given enough time. d) in many cases, phenotype is not merely determined by genotype, but by the environment as well.

1, 2, 4, and 5

According to the theory of sea-floor spreading, oceanic islands, such as the Hawaiian Islands depicted in the 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 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 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. There is a good chance of finding endemic species on this island. 5. On average, it should have fewer species per unit surface area than the other six islands.

linear

Anopheles mosquitoes, which carry the malaria parasite, cannot live above elevations of 5,900 feet. In addition, oxygen availability decreases with higher altitude. Consider a hypothetical human population that is adapted to life on the slopes of Mt. Kilimanjaro in Tanzania, a country in equatorial Africa. Mt. Kilimanjaro's base is about 2,600 feet above sea level and its peak is 19,341 feet above sea level. If the incidence of the sickle-cell allele in the population is plotted against altitude (feet above sea level), which of the following distributions is most likely, assuming little migration of people up or down the mountain?

500,000 years

Assuming that the rate of sea-floor spreading was constant during the 1-million-year period depicted in the figure, what should be the approximate age of marine fossils found in undisturbed sedimentary rock immediately overlying the igneous rock at the arrow labeled "II"?

2, 4, 1, 3

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

a

Based on the information presented in the accompanying figure, when both finches are found on the same island, what is the most likely factor to determine the difference in beak size? a) Competition b) Predation c) Nonrandom mating d) Genetic drift

d

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? a) reduced hybrid fertility b) mechanical isolation c) gametic isolation d) habitat isolation e) hybrid breakdown

a

Dogs (Canis lupus familiaris) and gray wolves (Canis lupus) can interbreed to produce viable, fertile offspring. These species shared a common ancestor recently (in geologic time) and have a high degree of genetic similarity, although their anatomies vary widely. Judging from this evidence, which two species concepts are most likely to place dogs and wolves together into a single species? a) biological and phylogenetic b) biological and morphological c) ecological and morphological d) morphological and phylogenetic e) ecological and phylogenetic

their feathers originally served as insulation, and only later became flight surfaces.

Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers. If some of these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be evidence supporting the claim that

around the base of Kauai, the oldest of the Hawaiian islands

Hawaii is the most southeastern of the seven islands and is also closest to the sea-floor spreading center from which the Pacific plate originates, which lies about 5,600 km further to the southeast. Assuming equal sedimentation rates, what should be the location of the thickest sediment layer and, thus, the area with the greatest diversity of fossils above the oceanic crust?

4 bands

How many other bands of sea-floor crust in the figure have the same magnetic polarity as the crust that directly straddles the rift valley?

c only

If a particular marine organism is fossilized in the sediments immediately overlying the igneous rock at the arrow labeled "II," at which other location(s), labeled A-E, would a search be most likely to find more fossils of this organism?

5

If one assumes that Hardy-Weinberg equilibrium applies to the population of colonists on this planet, about how many people will have attached earlobes when the planet's population reaches 1) 400 2)800 3) 10,000 4) 1,000 5)100

d

If the finch G. fortis established a population on Los Hermanos, based on the information shown in the graph, what would you predict would happen to the beak depth of G. fuliginosa over time? a) The beak depth would stay the same, but the beak would become longer. b) The beak depth would increase. c) The beak depth would not change d) The beak depth would decrease.

22,900

If the half-life of carbon-14 is about 5,730 years, then a fossil that has one-sixteenth the normal proportion of carbon-14 to carbon-12 should be about how many years old?

e

In order for speciation to occur, what must be true? a) Changes to centromere location or chromosome size must occur within the gene pool. b) Large numbers of genes that affect a single phenotypic trait must change. c) Large numbers of genes that affect numerous phenotypic traits must change. d) The number of chromosomes in the gene pool must change. e) At least one gene, affecting at least one phenotypic trait, must change.

c

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? a) disruptive selection b) stabilizing selection c) directional selection d) No selection would operate because the population is in Hardy-Weinberg equilibrium.

species selection

In the 5 to 7 million years that the hominid lineage has been diverging from its common ancestor with the great apes, dozens of hominid species have arisen, often with several species coexisting in time and space. As recently as 30,000 years ago, Homo sapiens coexisted with Homo neanderthalensis. Both species had large brains and advanced intellects. The fact that these traits were common to both species is most easily explained by which of the following?

a

In the Hardy-Weinberg equation, the pq in the term 2pq represents a) the heterozygotes' two different alleles. b) that the population is diploid. c) that the population is doubling in number. d) that heterozygotes can come about in two ways.

d

In the wild, male house finches (Carpodus mexicanus) vary considerably in the amount of red pigmentation in their head and throat feathers, with colors ranging from pale yellow to bright red. These colors come from carotenoid pigments that are found in the birds' diets; no vertebrates are known to synthesize carotenoid pigments. Thus, the brighter red the male's feathers are, the more successful he has been at acquiring the red carotenoid pigment by his food-gathering efforts (all other factors being equal). During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following is true of this situation? a) Alleles that promote more effective deposition of carotenoid pigments in the feathers of males should increase over the course of generations. b) Alleles that promote more efficient acquisition of carotenoid-containing foods by males should increase over the course of generations. c) There should be directional selection for bright red feathers in males. d) Three of the statements are correct. e) Two of the statements are correct.

species selection.

Many species of snakes lay eggs. However, in the forests of northern Minnesota where growing seasons are short, only live-bearing snake species are present. This trend toward species that perform live birth in a particular environment is an example of

a

Neutral theory proposes that a) a significant proportion of mutations are not acted upon by natural selection. b) DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R groups) have a neutral electrical charge. c) DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R groups) have a neutral pH. d) molecular clocks are more reliable when the surrounding pH is close to 7.0. e) most mutations of highly conserved DNA sequences should have no functional effect.

b

Part A Blue light is a portion of the visible spectrum that penetrates deep into bodies of water. Ultraviolet (UV) light, though, can penetrate even deeper. A gene within a population of marine fish that inhabits depths from 500 m to 1,000 m has an allele for a photopigment that is sensitive to UV light, and another allele for a photopigment that is sensitive to blue light. Which of the graphs in the figure best depicts the predicted distribution of these alleles within a population if the fish that carry these alleles prefer to locate themselves where they can see best?

a

Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. If pollen grains (which contain sperm cells) from one species are unable to germinate and make pollen tubes on female ovules (which contain egg cells) of the other species, then which of these terms is applicable? a) mechanical isolation b) reduced hybrid viability c) hybrid breakdown d) behavioral isolation

c

Speciation a) and macroevolution are synonymous. b) occurs only by the accumulation of genetic change over vast expanses of time. c) can involve changes to a single gene. d) must begin with the geographic isolation of a small, frontier population. e) occurs at such a slow pace that no one has ever observed the emergence of new species.

d

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? a) either A1 and A2, or B1 and B2 b) A1A3 and B1B3 have equal likelihoods of harboring snapping shrimp species that can hybridize. c) A3 and B3 d) A1 and B1 e) A5 and B5

c

The best classification system is that which most closely a) reflects the basic separation of prokaryotes from eukaryotes. b) conforms to traditional, Linnaean taxonomic practices. c) reflects evolutionary history. d) unites organisms that possess similar morphologies.

e

The difference between geographic isolation and habitat differentiation is the a) amount of genetic variation that occurs among two gene pools as speciation occurs. b) speed (tempo) at which two populations undergo speciation. c) the ploidy of the two populations as speciation occurs. d) identity of the phylogenetic kingdom or domain in which these phenomena occur. e) relative locations of two populations as speciation occurs.

All of the above statements are true.

The evolution of mammals from early tetrapods

in particular environments, similar adaptations can be beneficial in more than one species.

The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that

2 and 4

The first terrestrial organisms probably were considered which of the following? 1. burrowers 2. photosynthetic 3. multicellular 4. prokaryotes 5. eukaryotes 6. plants and their associated fungi

c

The importance of computers and of computer software to modern cladistics is most closely linked to advances in a) fossil discovery techniques. b) light microscopy. c) molecular genetics. d) Linnaean classification. e) radiometric dating.

a

The legless condition that is observed in several groups of extant reptiles is the result of a) several instances of the legless condition arising independently of each other. b) individual lizards adapting to a fossorial (living in burrows) lifestyle during their lifetimes. c) their common ancestor having been legless. d) a shared adaptation to an arboreal (living in trees) lifestyle.

e

The most important feature that permits a gene to act as a molecular clock is a) its being acted upon by natural selection. b) having a large number of base pairs. c) having a larger proportion of exonic DNA than of intronic DNA. d) its recent origin by a gene-duplication event. e) having a reliable average rate of mutation.

c

There are currently two large, permanent bridges that span the Panama Canal. The bridges are about 8 miles apart. If snapping shrimp avoid swimming at night and avoid swimming under shadows, then what do these bridges represent for the snapping shrimp? a) sources of refuge b) sources of a hybrid zone between the two bridges c) geographic barriers d) sources for increased gene flow

d

There is still some controversy among biologists about whether Neanderthals should be placed within the same species as modern humans or into a separate species of their own. Most DNA sequence data analyzed so far indicate that there was probably little or no gene flow between Neanderthals and Homo sapiens. Which species concept is most applicable in this example? a) ecological b) morphological c) phylogenetic d) biological

a variety of empty ecological niches, leading to adaptive radiation

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

a)

What is true of natural selection? a) Mutations occur at random; natural selection can preserve and distribute beneficial mutations. b) Natural selection creates beneficial mutations. c) The only way to eliminate harmful mutations is through natural selection. d) Natural selection is a random process. e) Mutations occur when directed by the good of the species; natural selection edits out harmful mutations and causes populations to adapt to the beneficial mutations.

a

What is true of the flightless cormorants of the Galápagos Islands? a) Flightless cormorants on one island have restricted gene flow with those on other islands, which could someday lead to a macroevolutionary event. b) They are descendants of the same common ancestor that gave rise to the unique finches of these islands. c) They are close relatives of flightless cormorants from the Americas. d) Their DNA has low levels of sequence homology with the DNA of flying American cormorants. e) If they are still able to breed successfully with flying cormorants, it would probably be with North American cormorants, rather than with South American cormorants.

It includes transitional forms with progressively specialized teeth.

What is true of the fossil record of mammalian origins?

a

What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains, rather than assigning all prokaryotes to the same kingdom? a) molecular b) nutritional c) anatomical d) ecological e) behavioral

b

When it acts upon a gene, which of the following processes consequently makes that gene an accurate molecular clock? a) reverse transcription b) mutation c) transcription d) proofreading e) directional natural selection

b

Which eukaryotic kingdom is polyphyletic, and therefore unacceptable, based on cladistics? a) Fungi b) Protista c) Monera d) Plantae e) Animalia

a

Which extinct species should be the best candidate to serve as the outgroup for the clade whose common ancestor occurs at position 2 in the figure? Use the figure to answer the following question. Which extinct species should be the best candidate to serve as the outgroup for the clade whose common ancestor occurs at position 2 in the figure? A B C D E

b

Which kind of DNA should provide the best molecular clock for determining the evolutionary relatedness of several species whose common ancestor became extinct billions of years ago? a) paralogous DNA that has lost its function (i.e., no longer codes for functional gene product) b) that coding for ribosomal RNA c) exonic DNA that codes for a noncrucial part of a polypeptide d) intronic DNA belonging to a gene whose product performs a crucial function e) mitochondrial DNA

b

Which kingdom has been replaced with two domains? a) Animalia b) Monera c) Fungi d) Plantae e) Protista

d

Which of the following are the best examples of homologous structures? a) owl wing and hornet wing b) eyelessness in the Australian mole and eyelessness in the North American mole c) bat wing and bird wing d) bones in the bat wing and bones in the human forelimb

e

Which of the following is a true statement concerning genetic variation? a) It arises in response to changes in the environment. b) It is created by the direct action of natural selection. c) It tends to be reduced by the processes involved when diploid organisms produce gametes. d) A population that has a higher average heterozygosity has less genetic variation than one with a lower average heterozygosity. e) It must be present in a population before natural selection can act upon the population.

b

Which of the following statements best summarizes evolution as it is viewed today? a) It is the descent of humans from the present-day great apes. b) It is a change in allele frequencies in a population over generations. c) It is synonymous with the process of gene flow. d) It represents the result of selection for acquired characteristics.

d

Which of these evolutionary trees represents the situation described in the previous paragraph? (Note: Yakuba (I) represents the island population, and yakuba (M) represents the mainland population.)

b

Which of these five species is the extant (i.e., not extinct) species that is most closely related to species X, and why is this so? a) This tree does not provide enough information to answer this question. b) V; shared a common ancestor with X most recently c) W; shared a common ancestor with X most recently d) Y; arose in the same fashion (i.e., at the same tempo) as X e) Z; shared a common ancestor with X most recently, and arose in the same fashion as X

c

Which of these would, if it had acted upon a gene, prevent this gene from acting as a reliable molecular clock? a) most substitution mutations involving an exonic codon's third position b) neutral mutations c) natural selection d) genetic drift e) mutations within introns

b

Which species is most closely related to species W? a) X is most closely related to species W. b) V is most closely related to species W. c) Y and Z are equally closely related to W. d) It is not possible to say from this tree.

b

Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true? a) The frequency of the strong-beak alleles increased in each bird as the drought persisted. b) Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted. c) Each bird evolved a deeper, stronger beak as the drought persisted. d) Each bird that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation.

e

You are maintaining a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after each generation. After several generations, you notice that the viability of the flies has decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, the best way to reverse this trend is to a) transfer only the largest flies. b) shock the flies with a brief treatment of heat or cold to make them more hardy. c) change the temperature at which you rear the flies. d) reduce the number of flies that you transfer at each generation. e) cross your flies with flies from another lab.