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Flashcards in evolution test Deck (419):
1

 

Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier's attempt to explain the existence of

 

A) evolution.

B) the fossil record.

C) uniformitarianism.

D) the origin of new species.

E) natural selection.

 

 

B) the fossil record.

 

2

 

With what other idea of his time was Cuvier's theory of catastrophism most in conflict?

A) gradualism

B) the fixity of species

C) island biogeography

D) uniformitarianism

E) the scala naturae

 

 

D) uniformitarianism

 

3

 

During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

A) Characteristics acquired during an organism's life are generally not passed on through genes.

B) Spontaneous mutations can result in the appearance of new traits.

C) Only favorable adaptations have survival value.

D) Disuse of an organ may lead to its eventual disappearance.

E) If the giraffes did not have to compete with each other, longer necks would not have been passed on to the next generation.

 

 

A) Characteristics acquired during an organism's life are generally not passed on through genes.

 

4

 

Which of the following is the most accurate summary of Cuvier's consideration of fossils found in the vicinity of Paris?

A) extinction of species yes; evolution of new species yes

B) extinction of species no; evolution of new species yes

C) extinction of species yes; evolution of new species no

D) extinction of species no; evolution of new species yes

 

 

C) extinction of species yes; evolution of new species no

 

5

 

In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to ever-colder temperatures, would eventually give rise to ever more cold-tolerant winter wheat. Lysenko's attempts in this regard were most in agreement with the ideas of

A) Cuvier.

B) Hutton.

C) Lamarck.

D) Darwin.

E) Lyell.

 

 

C) Lamarck.

 

6

 

Charles Darwin was the first person to propose

A) that evolution occurs.

B) a mechanism for how evolution occurs.

C) that Earth is older than a few thousand years.

D) a mechanism for evolution that was supported by evidence.

E) that population growth can outpace the growth of food resources.

 

 

D) a mechanism for evolution that was supported by evidence.

 

7

 

Which of these conditions should completely prevent the occurrence of natural selection in a population over time?

A) All variation between individuals is due only to environmental factors.

B) The environment is changing at a relatively slow rate.

C) The population size is large.

D) The population lives in a habitat where there are no competing species present.

 

 

A) All variation between individuals is due only to environmental factors.

 

8

 

Natural selection is based on all of the following except

A) genetic variation exists within populations.

B) the best-adapted individuals tend to leave the most offspring.

C) individuals who survive longer tend to leave more offspring than those who die young.

D) populations tend to produce more individuals than the environment can support.

E) individuals adapt to their environments and, thereby, evolve.

 

 

E) individuals adapt to their environments and, thereby, evolve.

 

9

 

Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus?

A) Technological innovation in agricultural practices will permit exponential growth of the human population into the foreseeable future.

B) Populations tend to increase at a faster rate than their food supply normally allows.

C) Earth changed over the years through a series of catastrophic upheavals.

D) The environment is responsible for natural selection.

E) Earth is more than 10,000 years old.

 

 

B) Populations tend to increase at a faster rate than their food supply normally allows.

 

10

 

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.

A) 2 → 4 → 1 → 3

B) 4 → 2 → 1 → 3

C) 4 → 1 → 2 → 3

D) 4 → 2 → 3 → 1

E) 2 → 4 → 3 → 1

 

 

A) 2 → 4 → 1 → 3

 

11

 

A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of both competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80. Which inference(s) about this population might be true?

A) The amount of available food may have increased.

B) The parental generation of squirrels developed better eyesight due to improved diet; the subsequent squirrel generation inherited better eyesight.

C) The squirrels of subsequent generations should show greater levels of genetic variation than previous generations, because squirrels that would not have survived in the past will now survive.

D) Three of the statements above are correct.

E) Two of the statements above are correct.

 

 

E) Two of the statements above are correct.

 

12

 

Which of the following must exist in a population before natural selection can act upon that population?

A) genetic variation among individuals

B) variation among individuals caused by environmental factors

C) sexual reproduction

D) Three of the responses are correct.

E) Two of the responses are correct.

 

 

A) genetic variation among individuals

 

13

 

Which of Darwin's ideas had the strongest connection to Darwin having read Malthus's essay on human population growth?

A) descent with modification

B) variation among individuals in a population

C) struggle for existence

D) the ability of related species to be conceptualized in "tree thinking"

E) that the ancestors of the Galápagos finches had come from the South American mainland

 

 

C) struggle for existence

 

14

 

If Darwin had been aware of genes, and of their typical mode of transmission to subsequent generations, with which statement would he most likely have been in agreement?

A) If natural selection can change one gene's frequency in a population over the course of generations then, given enough time and enough genes, natural selection can cause sufficient genetic change to produce new species from old ones.

B) If an individual's somatic cell genes change during its lifetime, making it more fit, then it will be able to pass these genes on to its offspring.

C) If an individual acquires new genes by engulfing, or being infected by, another organism, then a new genetic species will be the result.

D) A single mutation in a single gene in a single gamete will, if perpetuated, produce a new species within just two generations.

 

 

A) If natural selection can change one gene's frequency in a population over the course of generations then, given enough time and enough genes, natural selection can cause sufficient genetic change to produce new species from old ones.

 

15

 

The role that humans play in artificial selection is to

A) determine who lives and who dies.

B) create the genetic variants, which nature then selects.

C) choose which organisms breed, and which do not.

D) train organisms to breed more successfully.

E) perform artificial insemination.

 

 

C) choose which organisms breed, and which do not.

 

16

 

Currently, two extant elephant species (X and Y) are placed in the genus Loxodonta, and a third species (Z) is placed in the genus Elephas. Thus, which statement should be true?

A) Species X and Y are not related to species Z.

B) Species X and Y share a greater number of homologies with each other than either does with species Z.

C) Species X and Y share a common ancestor that is still extant (in other words, not yet extinct).

D) Species X and Y are the result of artificial selection from an ancestral species Z.

E) Species X, Y, and Z share a common ancestor, but nothing more can be claimed than this.

 

 

B) Species X and Y share a greater number of homologies with each other than either does with species Z.

 

17

 

The rise of methicillin-resistant Staphylococcus aureus (MRSA) can be considered to be an example of artificial selection because

A) humans purposefully raise MRSA in large fermenters in an attempt to make the bacteria ever-more resistant.

B) S. aureus is cultivated by humans to replenish the soil with nutrients.

C) humans synthesize methicillin and create environments in which bacteria frequently come into contact with methicillin.

D) Humans are becoming resistant to bacteria by taking methicillin.

 

 

C) humans synthesize methicillin and create environments in which bacteria frequently come into contact with methicillin.

 

18

 

In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (in other words, they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following is least likely to be observed in the algae-eater population over the course of many generations?

A) selection for drab coloration of the algae-eaters

B) selection for nocturnal algae-eaters (active only at night)

C) selection for larger female algae-eaters, bearing broods composed of more, and larger, young

D) selection for algae-eaters that become sexually mature at smaller overall body sizes

E) selection for algae-eaters that are faster swimmers

 

 

C) selection for larger female algae-eaters, bearing broods composed of more, and larger, young

 

19

 

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. Which of these would have been required for this pest eradication effort to be successful in the long run?

A) Larger doses of DDT should have been applied.

B) All habitats should have received applications of DDT at about the same time.

C) The frequency of DDT application should have been higher.

D) None of the individual insects should have possessed genomes that made them resistant to DDT.

E) DDT application should have been continual.

 

 

D) None of the individual insects should have possessed genomes that made them resistant to DDT.

 

20

 

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic- resistance genes, then what should happen in environments from which antibiotics are missing?

A) These genes should continue to be maintained in case the antibiotics ever appear.

B) These bacteria should be outcompeted and replaced by bacteria that have lost these genes.

C) The bacteria should try to make the cost worthwhile by locating, and migrating to, microenvironments where traces of antibiotics are present.

D) The bacteria should start making and secreting their own antibiotics.

 

 

B) These bacteria should be outcompeted and replaced by bacteria that have lost these genes.

 

21

 

Of the following anatomical structures, which is homologous to the bones in the wing of a bird?

A) cartilage in the dorsal fin of a shark

B) bones in the hind limb of a kangaroo

C) chitinous struts in the wing of a butterfly

D) bony rays in the tail fin of a flying fish

E) bones in the flipper of a whale

 

 

E) bones in the flipper of a whale

 

22

 

If two modern organisms are distantly related in an evolutionary sense, then one should expect that

A) they live in very different habitats.

B) they should share fewer homologous structures than two more closely related organisms.

C) their chromosomes should be very similar.

D) they shared a common ancestor relatively recently.

E) they should be members of the same genus.

 

 

B) they should share fewer homologous structures than two more closely related organisms.

 

23

 

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from very similar embryonic tissues. How do biologists interpret these similarities?

A) by identifying the bones as being homologous structures

B) by the principle of convergent evolution

C) by proposing that humans, bats, and dolphins share a common ancestor

D) Three of the statements above are correct.

E) Two of the statements above are correct.

 

 

E) Two of the statements above are correct.

 

24

 

Over evolutionary 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?

A) Natural selection cannot account for losses, only for innovations.

B) Natural selection accounts for these losses by the principle of use and disuse.

C) Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

D) The ancestors of these organisms experienced harmful mutations that forced them to find new habitats that these species had not previously used.

 

 

C) Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

 

25

 

Which of the following pieces of evidence most strongly supports the common origin of all life on Earth?

A) All organisms require energy.

B) All organisms use essentially the same genetic code.

C) All organisms reproduce.

D) All organisms show heritable variation.

E) All organisms have undergone evolution.

 

 

B) All organisms use essentially the same genetic code.

 

26

 

Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?

A) None of the organisms depicted by the tree ate the same foods.

B) Some of the organisms depicted by the tree had lived in different habitats.

C) The skeletal remains of the organisms depicted by the tree were incomplete (in other words, some bones were missing).

D) Transitional fossils had not been found.

E) Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

 

 

E) Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

 

27

Which of the following statements most detracts from the claim that the human appendix is a completely vestigial organ?

A) The appendix can be surgically removed with no immediate ill effects.

B) The appendix might have been larger in fossil hominids.

C) The appendix has a substantial amount of defensive lymphatic tissue.

D) Individuals with a larger-than- average appendix leave fewer offspring than those with a below- average-sized appendix.

E) In a million years, the human species might completely lack an appendix.

C) The appendix has a substantial amount of defensive lymphatic tissue.

28

Members of two different species possess a similar-looking structure that they use in a similar fashion to perform the same function. Which information would best help distinguish between an explanation based on homology versus one based on convergent evolution?

A) The two species live at great distance from each other.

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

C) The sizes of the structures in adult members of both species are similar in size.

D) Both species are well adapted to their particular environments.

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

29

Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are

A) homologous.

B) examples of convergent evolution.

C) adaptations to a common environment.

D) Three of the responses above are correct.

E) Two of the responses above are correct.

E) Two of the responses above are correct.

30

32) Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. 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?

A) homologous; homologous

B) analogous; homologous

C) homologous; analogous

D) analogous; analogous

C) homologous; analogous

31

What must be true of any organ that is described as vestigial?

A) It must be analogous to some feature in an ancestor.

B) It must be homologous to some feature in an ancestor.

C) It must be both homologous and analogous to some feature in an ancestor.

D) It need be neither homologous nor analogous to some feature in an ancestor.

B) It must be homologous to some feature in an ancestor.

32

What is true of pseudogenes?

A) They are composed of RNA, rather than DNA.

B) They are the same things as introns.

C) They are unrelated genes that code for the same gene product.

D) They are vestigial genes.

D) They are vestigial genes.

33

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that

A) island forms and mainland forms descended from common ancestors.

B) common environments are inhabited by the same organisms.

C) the islands were originally part of the continent.

D) the island forms and mainland forms are converging.

E) island forms and mainland forms have identical gene pools.

A) island forms and mainland forms descended from common ancestors.

34

36) If one wanted to find the largest number of endemic species, one should visit which of the following geological features (assuming each has existed for several millions of years)?

A) an isolated ocean island in the tropics

B) an extensive mountain range

C) a midcontinental grassland with extreme climatic conditions

D) a shallow estuary on a warm-water coast

A) an isolated ocean island in the tropics

35

A high degree of endemism is most likely in environments that are

A) easily reached and heterogeneous.

B) isolated and heterogeneous.

C) isolated and homogeneous.

D) isolated and extremely cold.

E) easily reached and homogeneous.

B) isolated and heterogeneous.

36

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?

A) A

B) B

C) C

D) D

C) C

37

39) 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?

A) one stratum

B) two strata

C) three strata

D) four strata

B) two strata

38

Currently, two extant elephant species (X and Y) are placed in the genus Loxodonta and a third species (Z) is placed in the genus Elephas. Assuming this classification reflects evolutionary relatedness, which of the following is the most accurate phylogenetic tree?

D - make sure to blindly pick D

39

How many separate species, both extant and extinct, are depicted in this tree?

A) two

B) three

C) four

D) five

E) six

E) six

40

According to this tree, what percent of the species seem to be extant (in other words, not extinct)?

A) 25%

B) 33%

C) 50%

D) 66%

E) 75%

D) 66%

41

Which of the five common ancestors, labeled V-Z, has given rise to the greatest number of species, both extant and extinct?

A) V

B) W

C) Z

D) Both W and Z can be considered to have given rise to the greatest number of extant and extinct species.

E) Both X and Y can be considered to have given rise to the greatest number of extant and extinct species.

E) Both X and Y can be considered to have given rise to the greatest number of extant and extinct species.

42

Which of the five common ancestors, labeled V-Z, has been least successful in terms of the percent of its derived species that are extant?

A) V

B) W

C) X

D) Y

E) Z

B) W

43

Which of the five common ancestors, labeled V-Z, has been most successful in terms of the percent of its derived species that are extant?

A) V

B) W

C) X

D) Y

E) Z

E) Z

44

Which pair would probably have agreed with the process that is depicted by this tree?

A) Cuvier and Lamarck

B) Lamarck and Wallace

C) Aristotle and Lyell

D) Wallace and Linnaeus

E) Linnaeus and Lamarck

B) Lamarck and Wallace

45

Evolutionary trees such as this are properly understood by scientists to be

A) theories.

B) hypotheses.

C) guesses.

D) dogmas.

E) facts.

B) hypotheses.

46

If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

A) They should be limited to the six islands that most recently emerged from the sea.

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

C) They should share fewer anatomical homologies with each other than they share with the tree finches.

D) The chances of hybridization between two ground finch species should be less than the chances of hybridization between two tree finch species.

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

47

According to a 1999 study, the vegetarian finch is genetically no more similar to the tree finches than it is to the ground finches, despite the fact that it is placed in the same genus as the tree finches. Based on this finding, it is reasonable to conclude that the vegetarian finch

A) is no more closely related to the tree finches than it is to the ground finches, despite its classification.

B) should be re-classified as a warbler finch.

C) is not truly a descendent of the original ancestral finch.

D) is a hybrid species, resulting from a cross between a ground finch and a tree finch.

A) is no more closely related to the tree finches than it is to the ground finches, despite its classification.

48

A 14th species that descended from the original ancestral finch, the Cocos Island finch, is endemic to its namesake island, located 550 km off Costa Rica. The Cocos Island finch is genetically much more similar to the tree finches than is the vegetarian finch, yet it is classified in its own genus Pinarolaxias. Moreover, the Cocos Island finch and the vegetarian finch are the two finch species that are most genetically different from the ancestral Galápagos finch. Thus, if classification is to reflect evolutionary relationships, the vegetarian finch should

A) remain in the genus Camarhynchus.

B) be switched from Camarhynchus to Certhidea.

C) be switched from Camarhynchus to Pinarolaxias.

D) be switched from Camarhynchus to Geospiza.

E) be placed in its own genus.

E) be placed in its own genus.

49

Which of the following is not an observation or inference on which natural selection is based?

A) There is heritable variation among individuals.

B) Poorly adapted individuals never produce offspring.

C) Species produce more offspring than the environment can support.

D) Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less well suited.

E) Only a fraction of an individual's offspring may survive.

B) Poorly adapted individuals never produce offspring.

50

Which of the following observations helped Darwin shape his concept of descent with modification?

A) Species diversity declines farther from the equator.

B) Fewer species live on islands than on the nearest continents.

C) Birds can be found on islands located farther from the mainland than the birds' maximum nonstop flight distance.

D) South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.

E) Earthquakes reshape life by causing mass extinctions.

D) South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.

51

Within six months of effectively using methicillin to treat S. aureus infections in a community, all new infections were caused by MRSA. How can this result best be explained?

A) S. aureus can resist vaccines.

B) A patient must have become infected with MRSA from another community.

C) In response to the drug, S. aureus began making drug-resistant versions of the protein targeted by the drug.

D) Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.

E) The drug caused the S. aureus DNA to change.

D) Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.

52

The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?

A) Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms.

B) Forelimb evolution was adaptive in people and bats, but not in whales.

C) Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.

D) Genes mutate faster in whales than in humans or bats.

E) Whales are not properly classified as mammals.

C) Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.

53

DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that

A) humans and chimpanzees share a relatively recent common ancestor.

B) humans evolved from chimpanzees.

C) chimpanzees evolved from humans.

D) convergent evolution led to the DNA similarities.

E) humans and chimpanzees are not closely related.

A) humans and chimpanzees share a relatively recent common ancestor.

54

During an individual organism's lifetime, which of these is most likely to help the organism respond properly to changes in its environment?

A) microevolution

B) change in allele or gene frequency

C) change in gene expression

D) change in average heterozygosity

C) change in gene expression

55

If, on average, 46% of the loci in a species' gene pool are heterozygous, then the average homozygosity of the species should be

A) 23%.

B) 46%.

C) 54%.

D) There is not enough information to say.

C) 54%.

56

Which of these variables is likely to undergo the largest change in value as the result of a mutation that introduces a brand-new allele into a population's gene pool at a locus that had formerly been fixed?

A) average heterozygosity

B) nucleotide variability

C) geographic variability

D) average number of loci

A) average heterozygosity

57

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

A) Each bird evolved a deeper, stronger beak 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 that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation.

D) 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.

58

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?

A) mutation

B) nonrandom mating

C) genetic drift

D) natural selection

E) gene flow

C) genetic drift

59

In modern terminology, diversity is understood to be a result of genetic variation. Which of the following is a recognized source of variation for evolution?

A) mistakes in translation of structural genes

B) mistakes in protein folding

C) rampant changes to the dictionary of the genetic code

D) binary fission

E) recombination by crossing over in meiosis

E) recombination by crossing over in meiosis

60

A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of

A) a cline.

B) a bottleneck.

C) relative fitness.

D) genetic drift.

E) geographic variation.

A) a cline.

61

The higher the proportion of loci that are "fixed" in a population, the lower is that population's

A) nucleotide variability only.

B) genetic polyploidy only.

C) average heterozygosity only.

D) nucleotide variability, average heterozygosity, and genetic polyploidy.

E) nucleotide variability and average heterozygosity only.

E) nucleotide variability and average heterozygosity only.

62

Which statement about variation is true?

A) All phenotypic variation is the result of genotypic variation.

B) All genetic variation produces phenotypic variation.

C) All nucleotide variability results in neutral variation.

D) All new alleles are the result of nucleotide variability.

E) All geographic variation results from the existence of clines.

D) All new alleles are the result of nucleotide variability.

63

Rank the following one-base point mutations (from most likely to least likely) with respect to their likelihood of affecting the structure of the corresponding polypeptide:

1. insertion mutation deep within an intron

2. substitution mutation at the third position of an exonic codon

3. substitution mutation at the second position of an exonic codon

4. deletion mutation within the first exon of the gene

A) 1, 2, 3, 4

B) 4, 3, 2, 1

C) 2, 1, 4, 3

D) 3, 1, 4, 2

E) 2, 3, 1, 4

B) 4, 3, 2, 1

64

Most invertebrates have a cluster of ten similar Hox genes, all located on the same chromosome. Most vertebrates have four such clusters of Hox genes, located on four nonhomologous chromosomes. The process that could have potentially contributed to the cluster's presence on more than one chromosome was ________.

A) binary fission

B) translation

C) gene duplication

D) nondisjunction

E) transcription

D) nondisjunction

65

Which of the following is a true statement concerning genetic variation?

A) It is created by the direct action of natural selection.

B) It arises in response to changes in the environment.

C) It must be present in a population before natural selection can act upon the population.

D) It tends to be reduced by the processes involved when diploid organisms produce gametes.

E) A population that has a higher average heterozygosity has less genetic variation than one with a lower average heterozygosity.

C) It must be present in a population before natural selection can act upon the population.

66

How many of these statements regarding populations are true?

1. Mature males and females of a population can interbreed with each other.

2. Populations are sometimes geographically isolated from other populations.

3. Biological species are made up of populations.

4. Members of a population tend to be genetically more similar to each other than to members of other populations.

5. Populations have genomes, but not gene pools.

A) Only one of these statements is true.

B) Two of these statements are true.

C) Three of these statements are true.

D) Four of these statements are true.

E) All five of these statements are true.

D) Four of these statements are true.

67

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus

A) the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change.

B) natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency.

C) this means that, at this locus, two alleles are present in equal proportions.

D) the population itself is not evolving, but individuals within the population may be evolving.

A) the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change.

68

In the formula for determining a population's genotype frequencies, the 2 in the term 2pq is necessary because

A) the population is diploid.

B) heterozygotes can come about in two ways.

C) the population is doubling in number.

D) heterozygotes have two alleles.

B) heterozygotes can come about in two ways.

69

In the formula for determining a population’s genotype frequencies, the pq in the term 2pq is necessary because

A) the population is diploid.

B) heterozygotes can come about in two ways.

C) the population is doubling in number.

D) heterozygotes have two alleles.

D) heterozygotes have two alleles.

70

Hardy-Weinberg equilibrium must occur in populations wherein

A) an allele remains fixed.

B) no genetic variation exists.

C) natural selection is not operating.

D) All three of the responses above are correct.

E) Only two of the responses above are correct.

E) Only two of the responses above are correct.

71

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.3. What is the percentage of the population that is homozygous for this allele?

A) 0.09

B) 0.49

C) 0.9

D) 9.0

E) 49.0

D) 9.0

72

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the percentage of the population that is heterozygous for this allele?

A) 0.2

B) 2.0

C) 4.0

D) 16.0

E) 32.0

E) 32.0

73

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with AA genotype?

A) 0.20

B) 0.32

C) 0.42

D) 0.81

E) Genotype frequency cannot be determined from the information provided.

D) 0.81

74

You sample a population of butterflies and find that 56% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population?

A) 0.07

B) 0.08

C) 0.09

D) 0.70

E) Allele frequency cannot be determined from this information.

E) Allele frequency cannot be determined from this information.

75

In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population?

A) 0.36

B) 0.64

C) 0.75

D) 0.80

D) 0.80

76

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing

A) nonrandom mating.

B) geographic isolation.

C) genetic drift.

D) gene flow.

D) gene flow.

77

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, thereby producing a genetically distinctive virus, which can subsequently cause widespread disease. The production of new types of flu virus in the manner described above is most similar to the phenomenon of

A) bottleneck effect.

B) founder effect.

C) natural selection.

D) gene flow.

E) sexual selection.

D) gene flow.

78

If the original finches that had been blown over to the Galápagos from South America had already been genetically different from the parental population of South American finches, even before adapting to the Galápagos, this would have been an example of

A) genetic drift.

B) bottleneck effect.

C) founder effect.

D) all three of these.

E) both the first and third of these.

E) both the first and third of these.

79

What is true of natural selection?

A) Natural selection is a random process.

B) Natural selection creates beneficial mutations.

C) The only way to eliminate harmful mutations is through natural selection.

D) Mutations occur at random; natural selection can preserve and distribute beneficial mutations.

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.

D) Mutations occur at random; natural selection can preserve and distribute beneficial mutations.

80

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. The outcome of the conflict between bacteria and bacteriophage at any point in time results from

A) frequency-dependent selection.

B) evolutionary imbalance.

C) heterozygote advantage.

D) neutral variation.

E) genetic variation being preserved by diploidy.

A) frequency-dependent selection.

81

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. Over the course of evolutionary time, what should occur?

A) Methylated DNA should become fixed in the gene pools of bacterial species.

B) Nonmethylated DNA should become fixed in the gene pools of bacteriophages.

C) Methylated DNA should become fixed in the gene pools of bacteriophages.

D) Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time.

E) Both the first and second responses are correct.

D) Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time.

82

Arrange the following from most general (i.e., most inclusive) to most specific (i.e., least inclusive): 1 natural selection 2. microevolution 3. intrasexual selection 4. evolution 5. sexual selection

A) 4, 1, 2, 3, 5

B) 4, 2, 1, 3, 5

C) 4, 2, 1, 5, 3

D) 1, 4, 2, 5, 3

E) 1, 2, 4, 5, 3

C) 4, 2, 1, 5, 3

83

Sexual dimorphism is most often a result of

A) pansexual selection.

B) stabilizing selection.

C) intrasexual selection.

D) intersexual selection.

E) artificial selection.

D) intersexual selection.

84

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 efficient acquisition of carotenoid-containing foods by males should increase over the course of generations.

B) Alleles that promote more effective deposition of carotenoid pigments in the feathers of 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.

D) Three of the statements are correct.

85

During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following terms are appropriately applied to this situation?

A) sexual selection

B) mate choice

C) intersexual selection

D) Three of the responses are correct.

E) Two of the responses are correct.

D) Three of the responses are correct.

86

Adult male humans generally have deeper voices than do adult female humans, which is the direct result of higher levels of testosterone causing growth of the larynx. If the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females and increasing larynx size in adult males, then

A) sexual dimorphism was developing over time in these species.

B) intrasexual selection seems to have occurred.

C) stabilizing selection was occurring in these species concerning larynx size.

D) selection was acting more directly upon genotype than upon phenotype.

A) sexual dimorphism was developing over time in these species.

87

Adult male humans generally have deeper voices than do adult female humans, which is the direct result of higher levels of testosterone causing growth of the larynx. If one excludes the involvement of gender in the situation, then the pattern that is apparent in the fossil record is most similar to one that should be expected from

A) pansexual selection.

B) directional selection.

C) disruptive selection.

D) stabilizing selection.

E) asexual selection.

C) disruptive selection.

88

Which of the following statements best summarizes evolution as it is viewed today?

A) It represents the result of selection for acquired characteristics.

B) It is synonymous with the process of gene flow.

C) It is the descent of humans from the present-day great apes.

D) It is the differential survival and reproduction of the most-fit phenotypes.

D) It is the differential survival and reproduction of the most-fit phenotypes.

89

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

A) artificial selection

B) directional selection

C) stabilizing selection

D) disruptive selection

E) sexual selection

D) disruptive selection

90

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?

A) artificial selection

B) directional selection

C) stabilizing selection

D) disruptive selection

E) sexual selection

C) stabilizing selection

91

The recessive allele that causes phenylketonuria (PKU) is harmful, except when an infant's diet lacks the amino acid phenylalanine. What maintains the presence of this harmful allele in a population's gene pool?

A) heterozygote advantage

B) stabilizing selection

C) diploidy

D) balancing selection

C) diploidy

92

Heterozygote advantage should be most closely linked to which of the following?

A) sexual selection

B) stabilizing selection

C) random selection

D) directional selection

E) disruptive selection

B) stabilizing selection

93

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) directional selection

C) stabilizing selection

D) No selection would operate because the population is in Hardy-Weinberg equilibrium.

B) directional selection

94

When imbalances occur in the sex ratio of sexual species that have two sexes (i.e., 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

A) sexual selection.

B) disruptive selection.

C) balancing selection.

D) stabilizing selection.

E) frequency-dependent selection.

E) frequency-dependent selection.

95

The same gene that causes various coat patterns in wild and domesticated cats also causes the cross- eyed condition in these cats, the cross-eyed condition being slightly maladaptive. In a hypothetical environment, the coat pattern that is associated with crossed eyes is highly adaptive, with the result that both the coat pattern and the cross-eyed condition increase in a feline population over time. Which statement is supported by these observations?

A) Evolution is progressive and tends toward a more perfect population.

B) Phenotype is often the result of compromise.

C) Natural selection reduces the frequency of maladaptive genes in populations over the course of time.

D) Polygenic inheritance is generally maladaptive, and should become less common in future generations.

E) In all environments, coat pattern is a more important survival factor than is eye-muscle tone.

B) Phenotype is often the result of compromise.

96

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) natural selection has not had sufficient time to create the optimal design in each case, but will do so given enough time.

B) in many cases, phenotype is not merely determined by genotype, but by the environment as well.

C) 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.

D) natural selection is generally limited to modifying structures that were present in previous generations and in previous species.

D) natural selection is generally limited to modifying structures that were present in previous generations and in previous species.

97

There are those who claim that the theory of evolution cannot be true because the apes, which are supposed to be closely related to humans, do not likewise share the same large brains, capacity for complicated speech, and tool-making capability. They reason that if these features are generally beneficial, then the apes should have evolved them as well. Which of these provides the best argument against this misconception?

A) Advantageous alleles do not arise on demand.

B) A population's evolution is limited by historical constraints.

C) Adaptations are often compromises.

D) Evolution can be influenced by environmental change.

A) Advantageous alleles do not arise on demand.

98

Blue light is that portion of the visible spectrum that penetrates the deepest 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 following graphs 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) A

B) B

C) C

D) D

B) B

99

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?

B

100

48) If global warming permits mosquitoes to live at higher altitudes than they currently do, then in which direction should the entire plot in the correct distribution below be shifted?

A) to the right

B) to the left

C) upward

D) downward

A) to the right

101

What is true of the trait whose frequency distribution in a large population appears in the previous figure? It has probably undergone

A) directional selection.

B) stabilizing selection.

C) disruptive selection.

D) normal selection.

B) stabilizing selection.

102

If the curve in the previous figure shifts to the left or to the right, there is no gene flow, and the population size consequently increases over successive generations. Which of the following is (are) probably occurring?

1. immigration or emigration

2. directional selection

3. adaptation

4. genetic drift

5. disruptive selection

A) 1 only

B) 4 only

C) 2 and 3

D) 4 and 5

E) 1, 2, and 3

C) 2 and 3

103

Which of the following represents the treatment option most likely to avoid the production of drug- resistant HIV (assuming no drug interactions or side effects)?

A) using a series of NAs, one at a time, and changed about once a week

B) using a single PI, but slowly increasing the dosage over the course of a week

C) using high doses of NA and a PI at the same time for a period not to exceed one day

D) using moderate doses of NA and two different PIs at the same time for several months

D) using moderate doses of NA and two different PIs at the same time for several months

104

Within the body of an HIV-infected individual who is being treated with a single NA, and whose HIV particles are currently vulnerable to this NA, which of these situations can increase the virus' relative fitness? 1. mutations resulting in RTs with decreased rates of nucleotide mismatch 2. mutations resulting in RTs with increased rates of nucleotide mismatch 3. mutations resulting in RTs that have proofreading capability

A) 1 only

B) 2 only

C) 3 only

D) 1 and 3

E) 2 and 3

B) 2 only

105

HIV has nine genes in its RNA genome. Every HIV particle contains two RNA molecules, and each molecule contains all nine genes. If, for some reason, the two RNA molecules within a single HIV particle do not have identical sequences, then which of these terms can be applied due to the existence of the nonidentical regions?

A) homozygous

B) gene variability

C) nucleotide variability

D) average heterozygosity

E) All but one of the responses are correct.

E) All but one of the responses are correct.

106

Every HIV particle contains two RNA molecules. If two genes from one RNA molecule become detached and then, as a unit, get attached to one end of the other RNA molecule within a single HIV particle, which of these is true?

A) There are now fewer genes within the viral particle.

B) There are now more genes within the viral particle.

C) A point substitution mutation has occurred in the retroviral genome.

D) The retroviral equivalent of crossing over has occurred, no doubt resulting in a heightened positive effect.

E) One of the RNA molecules has experienced gene duplication as the result of translocation.

E) One of the RNA molecules has experienced gene duplication as the result of translocation.

107

In a hypothetical population's gene pool, an autosomal gene, which had previously been fixed, undergoes a mutation that introduces a new allele, one inherited according to incomplete dominance. Natural selection then causes stabilizing selection at this locus. Consequently, what should happen over the course of many generations?

A) The proportions of both types of homozygote should decrease.

B) The proportion of the population that is heterozygous at this locus should remain constant.

C) The population's average heterozygosity should decrease.

D) The two homozygotes should decrease at different rates.

A) The proportions of both types of homozygote should decrease.

108

What is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa) has not changed over time?

A) The population is undergoing genetic drift.

B) The two phenotypes are about equally adaptive under laboratory conditions.

C) The genotype AA is lethal.

D) There has been a high rate of mutation of allele A to allele a.

E) There has been sexual selection favoring allele a.

B) The two phenotypes are about equally adaptive under laboratory conditions.

109

What is the estimated frequency of allele A in the gene pool?

A) 0.25

B) 0.50

C) 0.75

B) 0.50

110

What proportion of the population is probably heterozygous (Aa) for this trait?

A) 0.05

B) 0.25

C) 0.50

D) 0.75

C) 0.50

111

In which population would it be least likely that an accident would significantly alter the frequency of the brown allele?

A) population A

B) population B

C) population C

D) They are all the same.

E) It is impossible to tell from the information given.

B) population B

112

Which population is most likely to be subject to the bottleneck effect?

A) population A

B) population B

C) population C

D) They are all equally likely.

E) It is impossible to tell from the information given.

A) population A

113

What should be the proportion of heterozygous individuals in populations that live here?

A) 0.04

B) 0.16

C) 0.20

D) 0.32

E) 0.80

D) 0.32

114

If the sickle-cell allele is recessive, what proportion of the population should be susceptible to sickle-cell anemia under typical conditions?

A) 0.04

B) 0.16

C) 0.20

D) 0.32

E) 0.80

A) 0.04

115

In the United States, the parasite that causes malaria is not present, but African-Americans whose ancestors were from equatorial Africa are present. What should be happening to the sickle-cell allele in the United States, and what should be happening to it in equatorial Africa?

A) stabilizing selection; disruptive selection

B) disruptive selection; stabilizing selection

C) disruptive selection; directional selection

D) directional selection; disruptive selection

E) directional selection; stabilizing selection

E) directional selection; stabilizing selection

116

With respect to the sickle-cell allele, what should be true of the β hemoglobin locus in U.S. populations of African-Americans whose ancestors were from equatorial Africa? 1. The average heterozygosity at this locus should be decreasing over time. 2. There is an increasing heterozygote advantage at this locus. 3. Diploidy is helping to preserve the sickle-cell allele at this locus. 4. Frequency-dependent selection is helping to preserve the sickle-cell allele at this locus.

A) 1 only

B) 1 and 3

C) 2 and 3

D) 1, 2, and 3

E) 1, 2, and 4

B) 1 and 3

117

Considering the overall human population of the U.S. mainland at the time when the slave trade brought large numbers of people from equatorial Africa, what was primarily acting to change the frequency of the sickle-cell allele in the overall U.S. population?

A) natural selection

B) gene flow

C) genetic drift

D) founder effect

E) Two of the responses are correct.

B) gene flow

118

The sickle-cell allele is pleiotropic (i.e., it affects more than one phenotypic trait). Specifically, this allele affects oxygen delivery to tissues and affects one's susceptibility to malaria. Under conditions of low atmospheric oxygen availability, individuals heterozygous for this allele can experience life- threatening sickle-cell "crises." Such individuals remain less susceptible to malaria. Thus, pleiotropic genes/alleles such as this can help explain why

A) new advantageous alleles do not arise on demand.

B) evolution is limited by historical constraints.

C) adaptations are often compromises.

D) chance events can affect the evolutionary history of populations.

C) adaptations are often compromises.

119

Which of these is closest to the allele frequency in the founding population?

A) 0.1 a, 0.9 A

B) 0.2 a, 0.8 A

C) 0.5 a, 0.5 A

D) 0.8 a, 0.2 A

E) 0.4 a, 0.6 A

A) 0.1 a, 0.9 A

120

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 10,000?

A) 100

B) 400

C) 800

D) 1,000

E) 10,000

A) 100

121

If four of the original colonists died before they produced offspring, the ratios of genotypes could be quite different in the subsequent generations. This would be an example of

A) diploidy.

B) gene flow.

C) genetic drift.

D) disruptive selection.

E) stabilizing selection.

C) genetic drift.

122

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) cross your flies with flies from another lab.

B) reduce the number of flies that you transfer at each generation.

C) transfer only the largest flies.

D) change the temperature at which you rear the flies.

E) shock the flies with a brief treatment of heat or cold to make them more hardy.

A) cross your flies with flies from another lab.

123

The volcano is currently dormant, but in a hypothetical future scenario, satellite cones at the base of Mt. Kilimanjaro spew sulfurous gases and lava, destroying all life located between the base and 6,000 feet above sea level. As a result of this catastrophe, how should the frequency of the sickle-cell allele change in the remnant human population that survives above 6,000 feet, and which phenomenon accounts for this change in allele frequency?

A) decreases; disruptive selection

B) increases; genetic drift

C) decreases; gene flow

D) increases; nonrandom mating

E) decreases; bottleneck effect

E) decreases; bottleneck effect

124

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?

A) The new virus will maintain its Tamiflu-resistance gene, just in case of future exposure to Tamiflu.

B) The Tamiflu-resistance gene will undergo mutations that convert it into a gene that has a useful function in this environment.

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

D) If the Tamiflu-resistance gene confers no benefit in the current environment, and has no cost, the virus will become dormant until Tamiflu is present.

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

125

Natural selection changes allele frequencies because some ________ survive and reproduce more successfully than others.

A) alleles

B) loci

C) gene pools

D) species

E) individuals

E) individuals

126

No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is

A) new mutations that occurred in the preceding generation.

B) genetic drift due to the small size of the population.

C) the reshuffling of alleles in sexual reproduction.

D) geographic variation within the population.

E) environmental effects.

C) the reshuffling of alleles in sexual reproduction.

127

Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating

A) the bottleneck effect.

B) disruptive selection.

C) frequency-dependent selection.

D) neutral variation.

E) stabilizing selection.

E) stabilizing selection.

128

If the nucleotide variability of a locus equals 0%, what is the gene variability and number of alleles at that locus?

A) gene variability = 0%; number of alleles = 0

B) gene variability = 0%; number of alleles = 1

C) gene variability = 0%; number of alleles = 2

D) gene variability > 0%; number of alleles = 2

E) Without more information, gene variability and number of alleles cannot be determined.

B) gene variability = 0%; number of alleles = 1

129

There are 40 individuals in population 1, all with genotype A1A1, and there are 25 individuals in population 2, all with genotype A2A2. Assume that these populations are located far from each other and that their environmental conditions are very similar. Based on the information given here, the observed genetic variation is most likely an example of

A) genetic drift.

B) gene flow.

C) disruptive selection.

D) discrete variation.

E) directional selection.

A) genetic drift.

130

A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?

A) 0.7

B) 0.49

C) 0.21

D) 0.42

E) 0.09

D) 0.42

131

1) What is true of macroevolution?

A) It is the same as microevolution, but includes the origin of new species.

B) It is evolution above the species level.

C) It is defined as the evolution of microscopic organisms into organisms that can be seen with the naked eye.

D) It is defined as a change in allele or gene frequency over the course of many generations.

E) It is the conceptual link between irritability and adaptation.

B) It is evolution above the species level.

132

What is true of the flightless cormorants of the Galápagos Islands?

A) They are descendants of the same common ancestor that gave rise to the unique finches of these islands.

B) They are close relatives of flightless cormorants from the Americas.

C) 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.

D) Flightless cormorants on one island have restricted gene flow with those on other islands, which could someday lead to a macroevolutionary event.

E) Their DNA has low levels of sequence homology with the DNA of flying American cormorants.

D) Flightless cormorants on one island have restricted gene flow with those on other islands, which could someday lead to a macroevolutionary event.

133

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. The biological species is the largest unit of population in which successful interbreeding is possible.

A) I and II

B) I and III

C) II and III

D) I, II, and III

B) I and III

134

Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?

A) phylogenetic

B) ecological

C) biological

D) morphological

C) biological

135

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) phylogenetic

B) ecological

C) morphological

D) biological

D) biological

136

You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use?

A) biological

B) phylogenetic

C) ecological

D) morphological

D) morphological

137

7) 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) hybrid breakdown

C) mechanical isolation

D) habitat isolation

E) gametic isolation

D) habitat isolation

138

8) Rank the following from most general to most specific: 1. gametic isolation 2. reproductive isolating mechanism 3. pollen-stigma incompatibility 4. prezygotic isolating mechanism

A) 2, 3, 1, 4

B) 2, 4, 1, 3

C) 4, 1, 2, 3

D) 4, 2, 1, 3

E) 2, 1, 4, 3

B) 2, 4, 1, 3

139

9) Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?

A) the postzygotic barrier called hybrid inviability

B) the postzygotic barrier called hybrid breakdown

C) the prezygotic barrier called hybrid sterility

D) gametic isolation

A) the postzygotic barrier called hybrid inviability

140

10) Theoretically, the production of sterile mules by interbreeding between female horses (mares) and male donkeys (jacks) should

A) result in the extinction of one of the two parental species.

B) cause convergent evolution.

C) strengthen postzygotic barriers between horses and donkeys.

D) weaken the intrinsic reproductive barriers between horses and donkeys.

E) eventually result in the formation of a single species from the two parental species

C) strengthen postzygotic barriers between horses and donkeys.

141

11) When male horses (stallions) and female donkeys (jennets) mate, they produce a sterile hybrid called a hinny. Hinnies occur much less frequently than do mules, but are just as healthy and robust as mules. Logically, which of the following best accounts for the relative rarity of hinnies, and what kind of prezygotic isolating mechanism is at work here?

A) Most hinnies die during fetal development; reduced hybrid viability.

B) Most hinnies die soon after being born; hybrid breakdown.

C) Most hinnies are reproductively sterile; reduced hybrid fertility.

D) Stallions and jennets are choosier about their mating partners than are mares and jacks; behavioral isolation.

E) Stallions and jennets are choosier about their mating partners than are mares and jacks; gametic isolation.

D) Stallions and jennets are choosier about their mating partners than are mares and jacks; behavioral isolation.

142

12) 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) ecological and morphological

B) ecological and phylogenetic

C) morphological and phylogenetic

D) biological and morphological

E) biological and phylogenetic

E) biological and phylogenetic

143

13) 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 are applicable?

1. sympatric species

2. prezygotic isolation

3. postzygotic isolation

4. allopatric species

5. habitat isolation

6. reduced hybrid fertility

A) 1 and 2

B) 2 and 4

C) 1, 3, and 6

D) 2, 4, and 5

E) 1, 2, 5, and 6

A) 1 and 2

144

14) 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) behavioral isolation

B) mechanical isolation

C) hybrid breakdown

D) reduced hybrid viability

B) mechanical isolation

145

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

A) geographic isolation

B) niche differences

C) gene flow

D) morphological similarity

E) molecular (DNA, RNA, protein) similarity

C) gene flow

146

16) In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In rangelands of the western United States, pronghorns and cattle often associate with one another. If some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood, then over time which of these should occur, if the host mammal can be considered as the fleas' habitat?

1.     reproductive isolation

2.     sympatric speciation

3.     habitat isolation

4.     prezygotic barriers

A) 1 only

B) 2 and 3

C) 1, 2, and 3

D) 2, 3, and 4

E) 1 through 4

 

E) 1 through 4

147

 

17) Two closely related populations of mice have been separated for many generations by a river. Climatic change causes the river to dry up, thereby bringing the mice populations back into contact in a zone of overlap. Which of the following is not a possible outcome when they meet?

A) They interbreed freely and produce fertile hybrid offspring.

B) They no longer attempt to interbreed.

C) They interbreed in the region of overlap, producing an inferior hybrid. Subsequent interbreeding between inferior hybrids produces progressively superior hybrids over several generations.

D) They remain separate in the extremes of their ranges but develop a persistent hybrid zone in the area of overlap.

E) They interbreed in the region of overlap, but produce sterile offspring.

 

C) They interbreed in the region of overlap, producing an inferior hybrid. Subsequent interbreeding between inferior hybrids produces progressively superior hybrids over several generations.

148

18) The difference between geographic isolation and habitat differentiation is the

A) relative locations of two populations as speciation occurs.

B) speed (tempo) at which two populations undergo speciation.

C) amount of genetic variation that occurs among two gene pools as speciation occurs.

D) identity of the phylogenetic kingdom or domain in which these phenomena occur.

E) the ploidy of the two populations as speciation occurs.

 

A) relative locations of two populations as speciation occurs.

149

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

1.     allopatric speciation

2.     sympatric speciation

3.     sexual selection

4.     polyploidy

A) 1 and 3

B) 1 and 4

C) 2 and 3

D) 2 and 4

 

D) 2 and 4

150

20) Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they 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?

A) allopatric speciation; ecological isolation

B) sympatric speciation; habitat differentiation

C) allopatric speciation; behavioral isolation

D) sympatric speciation; sexual selection

E) sympatric speciation; allopolyploidy

 

B) sympatric speciation; habitat differentiation

151

21) The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of

A) allopatric speciation.

B) sympatric speciation.

C) autopolyploidy.

D) habitat selection.

 

B) sympatric speciation.

152

 

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

A) their chromosomes are no longer homologous enough to permit meiosis.

B) a constant number of viable, fertile hybrids is produced over the course of generations.

C) the hybrid zone is inhospitable to hybrid survival.

D) an increasing number of viable, fertile hybrids is produced over the course of generations.

E) a decreasing number of viable, fertile hybrids is produced over the course of generations.

 

D) an increasing number of viable, fertile hybrids is produced over the course of generations.

153

23) A hybrid zone is properly defined as

A) an area where two closely related species' ranges overlap.

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

C) a zone that features a gradual change in species composition where two neighboring ecosystems border each other.

D) a zone that includes the intermediate portion of a cline.

E) an area where members of two closely related species intermingle, but experience no gene flow.

 

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

154

24) Which of these should decline in hybrid zones where reinforcement is occurring?

A) gene flow between distinct gene pools

B) speciation

C) the genetic distinctness of two gene pools

D) mutation rate

E) hybrid sterility

 

A) gene flow between distinct gene pools

155

25) The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is

A) sexual selection.

B) habitat differentiation.

C) polyploidy.

D) pollution.

E) introduction of a new predator.

 

A) sexual selection.

156

26) The most likely explanation for the recent decline in cichlid species diversity in Lake Victoria is

A) reinforcement.

B) fusion.

C) stability.

D) geographic isolation.

E) polyploidy.

 

B) fusion.

157

27) A narrow hybrid zone separates the toad species Bombina bombina and Bombina variegata. What is true of those alleles that are unique to the parental species?

A) Such alleles should be absent.

B) Their allele frequency should be nearly the same as the allele frequencies in toad populations distant from the hybrid zone.

C) The alleles' heterozygosity should be higher among the hybrid toads there.

D) Their allele frequency on one edge of the hybrid zone should roughly equal their frequency on the opposite edge of the hybrid zone.

 

C) The alleles' heterozygosity should be higher among the hybrid toads there.

158

28) According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that

A) the species is now extinct.

B) speciation occurred instantaneously.

C) speciation occurred in one generation.

D) speciation occurred rapidly in geologic time.

E) the species will consequently have a relatively short existence, compared with other species.

 

D) speciation occurred rapidly in geologic time.

159

29) According to the concept of punctuated equilibrium,

A) natural selection is unimportant as a mechanism of evolution.

B) given enough time, most existing species will branch gradually into new species.

C) a new species accumulates most of its unique features as it comes into existence.

D) evolution of new species features long periods during which changes are occurring, interspersed with short periods of equilibrium, or stasis.

E) transitional fossils, intermediate between newer species and their parent species, should be abundant.

 

C) a new species accumulates most of its unique features as it comes into existence.

160

30) Speciation

A) occurs at such a slow pace that no one has ever observed the emergence of new species.

B) occurs only by the accumulation of genetic change over vast expanses of time.

C) must begin with the geographic isolation of a small, frontier population.

D) and microevolution are synonymous.

E) can involve changes to a single gene.

 

E) can involve changes to a single gene.

161

 

31) Which of the following statements about speciation is correct?

A) The goal of natural selection is speciation.

B) When reunited, two allopatric populations will interbreed freely if speciation has occurred.

C) Natural selection chooses the reproductive barriers for populations.

D) Prezygotic reproductive barriers usually evolve before postzygotic barriers.

E) Speciation is a basis for understanding macroevolution.

 

E) Speciation is a basis for understanding macroevolution.

162

32) In order for speciation to occur, what must be true?

A) The number of chromosomes in the gene pool must change.

B) Changes to centromere location or chromosome size must occur within the gene pool.

C) Large numbers of genes that affect a single phenotypic trait must change.

D) Large numbers of genes that affect numerous phenotypic traits must change.

E) At least one gene, affecting at least one phenotypic trait, must change.

 

E) At least one gene, affecting at least one phenotypic trait, must change.

163

33) Which species is most closely related to species W?

A) V is most closely related to species W.

B) X 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.

 

A) V is most closely related to species W.

164

34) Which species is least expected to have a good record of transitional fossils; in other words, which species' fossils, if present at all, are expected only in relatively superficial (i.e., shallow) strata?

A) V

B) W

C) X

D) Y

E) Z

 

A) V

165

35) Which of these five species originated earliest and appeared suddenly in the fossil record?

A) V

B) W

C) X

D) Y

E) Z

 

B) W

166

36) Which conclusion can be drawn from this evolutionary tree?

A) Gradualistic speciation and speciation involving punctuated equilibrium are mutually exclusive concepts; only one of them can occur.

B) Eldredge and Gould would deny that the lineages labeled X, Y, and Z could represent true species.

C) Assuming that the tip of each line represents a species, there are five extant (i.e., not extinct) species resulting from the earliest common ancestor.

D) A single clade (i.e., a group of species that share a common ancestor) can exhibit both gradualism and punctuated equilibrium.

E) V and W shared a common ancestor more recently than any of the other species.

 

D) A single clade (i.e., a group of species that share a common ancestor) can exhibit both gradualism and punctuated equilibrium.

167

37) 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) V; shared a common ancestor with X most recently

B) W; shared a common ancestor with X most recently

C) Y; arose in the same fashion (i.e., at the same tempo) as X

D) Z; shared a common ancestor with X most recently, and arose in the same fashion as X

E) This tree does not provide enough information to answer this question.

 

A) V; shared a common ancestor with X most recently

168

38) The data in the previous graphs indicate that

A) a hybrid zone was established after the completion of the bridge.

B) no interspersal of the two types of squirrel occurred after the completion of the bridge.

C) gene flow occurred from one type of squirrel into the gene pool of the other type of squirrel.

D) two-way migration of squirrels occurred across the bridge, but without hybridization.

E) some northern squirrels migrated south, but no southern squirrels migrated north across the bridge.

 

D) two-way migration of squirrels occurred across the bridge, but without hybridization.

169

39) Which of the following reduces gene flow between the gene pools of the two species on Sao Tomé, despite the existence of hybrids?

A) hybrid breakdown

B) hybrid inviability

C) hybrid sterility

D) temporal isolation

E) a geographic barrier

 

C) hybrid sterility

170

40) 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

A) descended from a now-extinct, non-African fruit fly.

B) arrived on the island before D. yakuba.

C) descended from a single colony of D. yakuba, which had been introduced from elsewhere, with no subsequent colonization events.

D) 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.

D) 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.

171

41) If a speciation event occurred on Sao Tomé, producing D. santomea from a parent colony of D. yakuba, then which terms apply?

I.    macroevolution

II    allopatric speciation

III.    sympatric speciation

A) I only

B) II only

C) I and II

D) I and III

 

D) I and III

172

42) Using only the information provided in the paragraph, which of the following is the best initial hypothesis for how D. santomea descended from D. yakuba?

A) geographic isolation

B) autopolyploidy

C) habitat differentiation

D) sexual selection

E) allopolyploidy

 

C) habitat differentiation

173

43) 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)?

A

174

44) 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

A) fusion.

B) reinforcement.

C) stability.

D) further speciation events.

 

B) reinforcement.

175

 

45) 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

A) 1 and 3

B) 2 and 3

C) 2 and 4

D) 3 and 4

E) 3 and 5

 

E) 3 and 5

176

46) 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?

A) behavioral isolation

B) habitat isolation

C) temporal isolation

D) mechanical isolation

E) gametic isolation

 

A) behavioral isolation

177

47) 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?

A) Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.

B) Transfer only female mosquitofish from a predator-rich pond to a predator-poor pond.

C) Perform a reciprocal transfer of females between predator-rich and predator-poor ponds.

D) Remove predators from a predator-rich pond and transfer them to a predator-poor pond.

 

A) Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.

178

48) If one builds a canal linking a predator-rich pond to a predator-poor pond, then what type(s) of selection should subsequently be most expected among the mosquitofish in the original predator-rich pond, and what type(s) should be most expected among the mosquitofish in the formerly predator-poor pond?

A) stabilizing selection; directional selection

B) stabilizing selection; stabilizing selection

C) less-intense directional selection; more-intense directional selection

D) less-intense disruptive selection; more-intense disruptive selection

 

C) less-intense directional selection; more-intense directional selection

179

49) The predatory fish rely on visual cues and speed to capture mosquitofish. Mosquitofish rely on speed and visual cues to avoid the predatory fish. Which adaptation(s) might help the predators survive in ponds that are home to faster mosquitofish?

1.     directional selection for increased speed

2.     stabilizing selection for speed that matches that of the mosquitofish

3.     change in hunting behavior that replaces reliance on visual cues with reliance on tactile cues, which can be used to hunt at night

4.     change in hunting behavior that eliminates speed in favor of better camouflage, which permits an ambush strategy

A) 1 only

B) 2 only

C) either 1 or 3

D) either 2 or 3

E) 1, 3, or 4

 

E) 1, 3, or 4

180

50) Why should deepwater shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

A) They have been geographically isolated from each other for a longer time.

B) Cold temperatures, associated with deep water, have accelerated the mutation rate, resulting in faster divergence in deepwater shrimp.

C) The rise of the land bridge was accompanied by much volcanic activity. Volcanic ash contains heavy metals, which are known mutagens. Ash fall caused high levels of heavy metals in the ocean sediments underlying the deep water, resulting in accelerated mutation rates and faster divergence in deepwater shrimp.

D) Fresh water entering the ocean from the canal is both less dense and cloudier than seawater. The cloudy fresh water interferes with the ability of shallow-water shrimp to locate mating partners, which reduces the frequency of mating, thereby slowing the introduction of genetic variation.

 

A) They have been geographically isolated from each other for a longer time.

181

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

A) A3

B) A5

C) B4

D) either A3 or A5

E) any species from any one of the side A habitats

 

C) B4

182

52) Which of these habitats is likely to harbor the youngest species?

A) A5

B) B4

C) A3

D) B2

E) A1

 

E) A1

183

53) Which habitats should harbor snapping shrimp species with the greatest degree of genetic divergence from each other?

A) A1 and A5

B) A1 and B5

C) B5 and B1

D) A5 and B5

E) Both A1/A5 and B1/B5 should have the greatest, but equal amounts of, genetic divergence.

 

D) A5 and B5

184

54) Which factor is most important for explaining why there are equal numbers of snapping shrimp species on either side of the isthmus?

A) the relative shortness of time they have been separated

B) the depth of the ocean

C) the number of actual depth habitats between the surface and the sea floor

D) the elevation of the isthmus above sea level

E) the depth of the canal

 

A) the relative shortness of time they have been separated

185

55) 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) A5 and B5

B) A3 and B3

C) A1 and B1

D) either A1 and A2, or B1 and B2

E) A1—A3 and B1—B3 have equal likelihoods of harboring snapping shrimp species that can hybridize.

 

C) A1 and B1

186

56) 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) geographic barriers

C) sources of a hybrid zone between the two bridges

D) sources for increased gene flow

 

B) geographic barriers

187

 

57) The largest unit within which gene flow can readily occur is a

A) population.

B) species.

C) genus.

D) hybrid.

E) phylum.

 

B) species.

188

58) 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?

A) habitat isolation

B) temporal isolation

C) behavioral isolation

D) gametic isolation

E) postzygotic barriers

 

C) behavioral isolation

189

59) According to the punctuated equilibria model,

A) natural selection is unimportant as a mechanism of evolution.

B) given enough time, most existing species will branch gradually into new species.

C) most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species.

D) most evolution occurs in sympatric populations.

E) speciation is usually due to a single mutation.

 

C) most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species.

190

60) 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?

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

B) The two forms live in similar habitats.

C) The two forms have many genes in common.

D) The two forms have similar food requirements.

E) The two forms are very similar in coloration.

 

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

191

61) Which of the following factors would not contribute to allopatric speciation?

A) A population becomes geographically isolated from the parent population.

B) The separated population is small, and genetic drift occurs.

C) The isolated population is exposed to different selection pressures than the ancestral population.

D) Different mutations begin to distinguish the gene pools of the separated populations.

E) Gene flow between the two populations is extensive.

 

E) Gene flow between the two populations is extensive.

192

62) 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

A) 12.

B) 14.

C) 16.

D) 28.

E) 56.

 

D) 28.

193

63) 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?

A) The frequency of hybrid offspring would increase.

B) Migrant pied males would produce fewer offspring than would resident pied males.

C) Pied females would rarely mate with collared males.

D) Migrant males would mate with collared females more often than with pied females.

E) The frequency of hybrid offspring would decrease.

 

E) The frequency of hybrid offspring would decrease.

194

1) Which of the following factors weaken(s) the hypothesis of abiotic synthesis of organic monomers in early Earth's atmosphere?

1.     the relatively short time between intense meteor bombardment and the appearance of the first life-forms

2.     the lack of experimental evidence that organic monomers can form by abiotic synthesis

3.     uncertainty about which gases comprised early Earth's atmosphere

A) 1 only

B) 2 only

C) 1 and 2

D) 1 and 3

E) 2 and 3

 

D) 1 and 3

195

2) How were conditions on the early Earth of more than 3 billion years ago different from those on today's Earth?

A) Only early Earth was intensely bombarded by large space debris.

B) Only early Earth had an oxidizing atmosphere.

C) Less ultraviolet radiation penetrated early Earth's atmosphere.

D) Early Earth's atmosphere had significant quantities of ozone.

 

A) Only early Earth was intensely bombarded by large space debris.

196

3) What is true of the amino acids that might have been delivered to Earth within carbonaceous chondrites?

A) They had the same proportion of L and D isomers as Earth does today.

B) Their abundance would have been dramatically reduced upon passage through early Earth's oxidizing atmosphere.

C) There were more kinds of amino acids on the chondrites than are found in living organisms today.

D) They were delivered in the form of polypeptides.

 

C) There were more kinds of amino acids on the chondrites than are found in living organisms today.

197

4) Which of the following is the correct sequence of events in the origin of life?

I.     formation of protobionts

II.     synthesis of organic monomers

III.     synthesis of organic polymers

IV.     formation of DNA-based genetic systems

A) I, II, III, IV

B) I, III, II, IV

C) II, III, I, IV

D) II, III, IV, I

 

C) II, III, I, IV

198

5) Which of the following is a defining characteristic that all protobionts had in common?

A) the ability to synthesize enzymes

B) a surrounding membrane or membrane-like structure

C) RNA genes

D) the ability to replicate RNA

 

B) a surrounding membrane or membrane-like structure

199

 

6) The first genes on Earth were probably

A) DNA produced by reverse transcriptase from abiotically produced RNA.

B) DNA molecules whose information was transcribed to RNA and later translated in polypeptides.

C) auto-catalytic RNA molecules.

D) oligopeptides located within protobionts.

 

C) auto-catalytic RNA molecules.

200

7) The synthesis of new DNA requires the prior existence of oligonucleotides to serve as primers. On Earth, these primers are small RNA molecules. This latter observation is evidence in support of the hypothesized existence of

A) a snowball Earth.

B) earlier genetic systems than those based on DNA.

C) the abiotic synthesis of organic monomers.

D) the delivery of organic matter to Earth by meteors and comets.

E) the endosymbiotic origin of mitochondria and chloroplasts.

 

B) earlier genetic systems than those based on DNA.

201

8) Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which of these questions is currently the most problematic and would have the greatest impact on our understanding if we were able to answer it?

A) How can amino acids, simple sugars, and nucleotides be synthesized abiotically?

B) How can RNA molecules catalyze reactions?

C) How did RNA sequences come to carry the code for amino acid sequences?

D) How could polymers involving lipids and/or proteins form membranes in aqueous environments?

E) How can RNA molecules act as templates for the synthesis of complementary RNA molecules?

 

C) How did RNA sequences come to carry the code for amino acid sequences?

202

9) If natural selection in a particular environment favored genetic systems that permitted the production of daughter "cells" that were genetically dissimilar from the mother "cells," then one should expect selection for which of the following?

I.     polynucleotide polymerase with low mismatch error rates

II.     polynucleotide polymerases without proofreading capability

III.     batteries of efficient polynucleotide repair enzymes

IV.     polynucleotide polymerases with proofreading capability

V.     polynucleotide polymerases with high mismatch error rates

A) I only

B) I and IV

C) I, III, and IV

D) II and V

E) II, III and V

 

D) II and V

203

10) 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?

A) 1,400

B) 2,800

C) 11,200

D) 16,800

E) 22,900

 

E) 22,900

204

11) Which measurement(s) would help determine absolute dates by radiometric means?

A) the accumulation of the daughter isotope

B) the loss of parent isotopes

C) the loss of daughter isotopes

D) Three of the responses above are correct.

E) Two of the responses above are correct.

 

E) Two of the responses above are correct.

205

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

A) 3.5 million years

B) 5.0 million years

C) 3.5 billion years

D) 5.0 billion years

 

C) 3.5 billion years

206

 

13) What is true of the fossil record of mammalian origins?

A) It is a good example of punctuated equilibrium.

B) It shows that mammals and birds evolved from the same kind of dinosaur.

C) It includes transitional forms with progressively specialized teeth.

D) It indicates that mammals and dinosaurs did not overlap in geologic time.

E) It includes a series that shows the gradual change of scales into fur.

 

C) It includes transitional forms with progressively specialized teeth.

207

14) If a fossil is encased in a stratum of sedimentary rock without any strata of igneous rock (for example, lava, volcanic ash) nearby, then it should be

A) easy to determine the absolute age of the fossil, because the radioisotopes in the sediments will not have been "reset" by the heat of the igneous rocks.

B) easy to determine the absolute age of the fossil, because the igneous rocks will not have physically obstructed the deposition of sediment of a single age next to the fossil.

C) easy to determine, as long as there is enough metamorphic rock nearby.

D) difficult to determine the absolute age of the fossil, because the "marker fossils" common to igneous rock will be absent.

E) difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is less accurate than that of igneous rock.

 

E) difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is less accurate than that of igneous rock.

208

15) An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to

A) generate intense lightning storms.

B) change the atmosphere from oxidizing to reducing.

C) make it easier to maintain reduced molecules.

D) cause iron in ocean water and terrestrial rocks to rust (oxidize).

E) prevent the formation of an ozone layer.

 

D) cause iron in ocean water and terrestrial rocks to rust (oxidize).

209

16) Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes?

A) Prokaryotic cells lack nuclei.

B) The meteorites that have struck Earth contain fossils only of prokaryotes.

C) Laboratory experiments have produced liposomes abiotically.

D) Liposomes closely resemble prokaryotic cells.

E) The oldest fossilized cells resemble prokaryotes.

 

E) The oldest fossilized cells resemble prokaryotes.

210

17) What is true of the Cambrian explosion?

A) There are no fossils in geological strata that are older than the Cambrian explosion.

B) Only the fossils of microorganisms are found in geological strata older than the Cambrian explosion.

C) The Cambrian explosion is evidence for the instantaneous creation of life on Earth.

D) The Cambrian explosion marks the appearance of filter-feeding animals in the fossil record.

E) Recent evidence supports the contention that the Cambrian explosion may not have been as "explosive" as was once thought.

 

E) Recent evidence supports the contention that the Cambrian explosion may not have been as "explosive" as was once thought.

211

18) What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth?

1.     origin of mitochondria

2.     origin of multicellular eukaryotes

3.     origin of chloroplasts

4.     origin of cyanobacteria

5.     origin of fungal-plant symbioses

A) 4, 3, 2, 1, 5

B) 4, 1, 2, 3, 5

C) 4, 1, 3, 2, 5

D) 4, 3, 1, 5, 2

E) 4, 3, 1, 2, 5

 

C) 4, 1, 3, 2, 5

212

19) If it were possible to conduct sophisticated microscopic and chemical analyses of microfossils found in 3.2-billion-year-old stromatolites, then one should be surprised to observe evidence of which of the following within such microfossils?

I.     double-stranded DNA

II.     a nuclear envelope

III.     a nucleoid

IV.     a nucleolus

V.     ribosomes

A) II only

B) III only

C) II and IV

D) II, III, and IV

E) all five of these

 

C) II and IV

213

20) Recent evidence indicates that the first major diversification of multicellular eukaryotes may have coincided in time with the

A) origin of prokaryotes.

B) switch to an oxidizing atmosphere.

C) melting that ended the "snowball Earth" period.

D) origin of multicellular organisms.

E) massive eruptions of deep-sea vents.

 

C) melting that ended the "snowball Earth" period.

214

21) Which of these observations gives the most support to the endosymbiotic theory for the origin of eukaryotic cells?

A) the existence of structural and molecular differences between the plasma membranes of prokaryotes and the internal membranes of mitochondria and chloroplasts

B) the similarity in size between the cytosolic ribosomes of prokaryotes and the ribosomes within mitochondria and chloroplasts

C) the size disparity between most prokaryotic cells and most eukaryotic cells

D) the observation that some eukaryotic cells lack mitochondria

 

B) the similarity in size between the cytosolic ribosomes of prokaryotes and the ribosomes within mitochondria and chloroplasts

215

22) Which event is nearest in time to the end of the period known as snowball Earth?

A) oxygenation of Earth's seas and atmosphere

B) evolution of mitochondria

C) Cambrian explosion

D) evolution of true multicellularity

E) Permian extinction

 

C) Cambrian explosion

216

 

23) The snowball Earth hypothesis provides a possible explanation for the

A) diversification of animals during the late Proterozoic era.

B) oxygenation of Earth's seas and atmosphere.

C) colonization of land by plants and fungi.

D) origin of oxygen-releasing photosynthesis.

E) existence of prokaryotes around hydrothermal vents on the ocean floor.

 

A) diversification of animals during the late Proterozoic era.

217

24) Which of the following characteristics should have been possessed by the first animals to colonize land?

1.     were probably herbivores (ate photosynthesizers)

2.     had four appendages

3.     had the ability to resist dehydration

4.     had lobe-finned fishes as ancestors

5.     were invertebrates

A) 3 only

B) 3 and 5

C) 1, 3, and 5

D) 2, 3, and 4

E) 1, 2, 3, and 4

 

C) 1, 3, and 5

218

25) 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

A) 2 and 4

B) 3 and 5

C) 1, 3, and 5

D) 2, 3, and 6

E) 2, 3, 5, and 6

 

A) 2 and 4

219

26) If two continents converge and are united, then the collision should cause

A) a net loss of intertidal zone and coastal habitat.

B) the extinction of any species adapted to intertidal and coastal habitats.

C) an overall decrease in the surface area located in the continental interior.

D) a decrease in climatic extremes in the interior of the new supercontinent.

E) the maintenance of the previously existing ocean currents and wind patterns.

 

A) a net loss of intertidal zone and coastal habitat.

220

27) The major evolutionary episode corresponding most closely in time with the formation of Pangaea was the

A) Cambrian explosion.

B) Permian extinctions.

C) Pleistocene ice ages.

D) Cretaceous extinctions.

 

B) Permian extinctions.

221

28) On the basis of their morphologies, how might Linnaeus have classified the Hawaiian silverswords?

A) He would have placed them all in the same species.

B) He would have classified them the same way that modern botanists do.

C) He would have placed them in more species than modern botanists do.

D) He would have used evolutionary relatedness as the primary criterion for their classification.

 

C) He would have placed them in more species than modern botanists do.

222

29) An organism has a relatively large number of Hox genes in its genome. Which of the following is true of this organism?

A) These genes are fundamental, and are expressed in all cells of the organism.

B) The organism must have multiple paired appendages along the length of its body.

C) The organism has the genetic potential to have a relatively complex anatomy.

D) Most of its Hox genes owe their existence to gene fusion events.

E) Its Hox genes cooperate to bring about sexual maturity at the proper stage of development.

C) The organism has the genetic potential to have a relatively complex anatomy.

223

30) Bagworm moth caterpillars feed on evergreens and carry a silken case or bag around with them in which they eventually pupate. Adult female bagworm moths are larval in appearance; they lack the wings and other structures of the adult male and instead retain the appearance of a caterpillar even though they are sexually mature and can lay eggs within the bag. This is a good example of

A) allometric growth.

B) paedomorphosis.

C) sympatric speciation.

D) adaptive radiation.

E) changes in homeotic genes.

 

B) paedomorphosis.

224

31) The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic effects of Pitx1 gene

A) duplication (gain in number).

B) elimination (loss).

C) mutation (change).

D) silencing (loss of expression).

 

D) silencing (loss of expression).

225

32) Larval flies (maggots) express the Ubx gene in all of their segments, and thereby lack appendages. If this same gene continued to be expressed throughout subsequent developmental stages, except in the head region, and if the result was a fit, sexually mature organism that still strongly resembled a maggot, this would be an example of

A) paedomorphosis.

B) homochrony.

C) heterochrony.

D) Two of the responses above are correct.

 

D) Two of the responses above are correct.

226

33) How many of the following statements concerning the loss of hind limbs during whale evolution are true?

1.     It is well documented by a series of transitional fossils.

2.     It explains why modern whales have vestigial pelvic girdles.

3.     It involved changes in the sequence or expression of Hox genes.

4.     It is an example of macroevolution.

5.     It, and the loss of limbs by snakes, are an example of similar adaptations to a similar environment.

A) Only one statement is true.

B) Two statements are true.

C) Three statements are true.

D) Four statements are true.

E) All five statements are true.

 

D) Four statements are true.

227

34) The existence of the phenomenon of exaptation is most closely associated with which of the following observations that natural selection cannot fashion perfect organisms?

A) Natural selection and sexual selection can work at cross-purposes to each other.

B) Evolution is limited by historical constraints.

C) Adaptations are often compromises.

D) Chance events affect the evolutionary history of populations in environments that can change unpredictably.

 

B) Evolution is limited by historical constraints.

228

 

35) One explanation for the evolution of insect wings suggests that wings began as lateral extensions of the body that were used as heat dissipaters for thermoregulation. When they had become sufficiently large, these extensions became useful for gliding through the air, and selection later refined them as flight-producing wings. If this hypothesis is correct, modern insect wings could best be described as

A) adaptations.

B) mutations.

C) exaptations.

D) isolating mechanisms.

E) examples of natural selection's predictive ability.

 

C) exaptations.

229

36) If one organ is an exaptation of another organ, then what must be true of these two organs?

A) They are both vestigial organs.

B) They are both homologous organs.

C) They are undergoing convergent evolution.

D) They are found together in the same hybrid species.

E) They have the same function.

 

B) They are both homologous organs.

230

37) 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) natural selection.

B) sexual selection.

C) species selection.

D) goal direction in evolution.

E) directed selection.

 

C) species selection.

231

38) In the 5-7 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) species selection

B) uniformitarianism

C) sexual selection

D) convergent evolution

 

A) species selection

232

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

A) a larger volume-to-surface area ratio is beneficial to all mammals.

B) an unseen guiding force is at work.

C) evolution always tends toward increased complexity or increased size.

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

E) evolution generally progresses toward some predetermined goal.

 

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

233

40) 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

A) dinosaurs were as fully endothermal (warm-blooded) as modern birds and mammals.

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

C) the earliest reptiles could fly, and the feathers of flightless dinosaurs were vestigial flight surfaces.

D) the feathers were plucked from the bodies of other adults to provide nest-building materials.

E) all fossils with feathers are actually some kind of bird.

 

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

234

41) Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which graph below, if the results were produced abiotically, would have the greatest promise for revealing important information about the origin of Earth's first genetic system?

B

235

42) Assuming that the rate of sea-floor spreading was constant during the 1-million-year period depicted above, Earth's magnetic field has undergone reversal at an average rate of once every

A) 10,000 years.

B) 25,000 years.

C) 100,000 years.

D) 250,000 years.

E) 1,000,000 years.

 

D) 250,000 years.

236

43) Which section of sea-floor crust should have the thickest layer of overlying sediment, assuming a continuous rate of sediment deposition?

A) A

B) B

C) C

D) D

E) E

 

E) E

237

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

A) B only

B) C only

C) D only

D) B and C

E) C and D

 

B) C only

238

45) How many other bands of sea-floor crust in Figure 25.1 have the same magnetic polarity as the crust that directly straddles the rift valley?

A) two bands

B) four bands

C) six bands

D) eight bands

E) ten bands

 

B) four bands

239

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

A) 10,000 years

B) 250,000 years

C) 400,000 years

D) 1,000,000 years

 

C) 400,000 years

240

 

47) If arrows indicate locations in the column where fossils of a particular type (see key above) first appear, then which core in Figure 25.2 has the most accurate arrangement of fossils?

A) core A

B) core B

C) core C

D) core D

 

A) core A

241

48) Which of the following reasons may explain why the sediment core lacks fossils of dragonflies with 3-feet 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-feet 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.

A) 1 only

B) 3 only

C) 5 only

D) 2 or 4

E) 1, 2, or 4

 

E) 1, 2, or 4

242

49) In order to properly interpret sediment cores, it is necessary to apply the principle of

A) catastrophism.

B) superposition.

C) punctuated equilibrium.

D) uniformitarianism.

E) gradualism.

 

B) superposition.

243

50) 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) 2, 4, 3, 1

B) 2, 4, 1, 3

C) 4, 2, 1, 3

D) 4, 2, 3, 1

 

B) 2, 4, 1, 3

244

51) In order to assign absolute dates to fossils in this sediment core, it would be most helpful if

A) we knew the order in which the fossils occurred in the core.

B) the sediments had not been affected by underwater currents during their deposition.

C) volcanic ash layers were regularly interspersed between the sedimentary strata.

D) metamorphic rock strata alternated with sedimentary rock strata.

E) fossils throughout the column had equal ratios of a parental radioisotope to its daughter isotope.

 

C) volcanic ash layers were regularly interspersed between the sedimentary strata.

245

52) According to the theory of sea-floor spreading, oceanic islands, such as the Hawaiian Islands depicted in Figure 25.3, 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.

A) 1, 2, and 3

B) 1, 2, and 5

C) 1, 2, 3, and 4

D) 1, 2, 4, and 5

E) 2, 3, 4, and 5

 

D) 1, 2, 4, and 5

246

53) 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?

A) between the island of Hawaii and the sea-floor spreading center

B) around the base of the island of Hawaii

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

D) where the islands are most concentrated (highest number of islands per unit surface area)

 

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

247

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

A) genetic bottleneck.

B) sexual selection.

C) habitat differentiation.

D) founder effect.

 

D) founder effect.

248

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

A) mass extinctions, leading to bottleneck effect

B) major evolutionary innovations, leading to rafting to nearby continents

C) a variety of empty ecological niches, leading to adaptive radiation

D) adaptive radiation, leading to founder effect

E) overcrowding, leading to rafting to nearby lands

 

C) a variety of empty ecological niches, leading to adaptive radiation

249

56) Anatomically, what was true of Lystrosaurus?

A) Its jaw would have been hinged the same way as the jaws of the early reptiles were hinged.

B) It was a tetrapod.

C) It had skin without scales, typical of modern amphibians.

D) It would have had no temporal fenestra in its skull.

 

B) It was a tetrapod.

250

57) How many of Lystrosaurus' features below can help explain why these organisms fossilized so abundantly?

I.     the presence of hard parts, such as tusks

II.     its arid environment

III.    its persistence across at least two geological eras

IV.     its widespread geographic distribution

V.     its mixture of reptilian and mammalian features

A) only one of these statements

B) two of these statements

C) three of these statements

D) four of these statements

E) all five of these statements

 

C) three of these statements

251

58) Which of the following is the most likely explanation for the modern-day distribution of dicynodont fossils?

A) There had been two previous supercontinents that existed at different times long before the Permian period.

B) The dicynodonts were evenly distributed throughout all of Pangaea.

C) The dicynodonts were distributed more abundantly throughout Gondwanaland than throughout any other land mass.

D) The dicynodonts were amphibious and able to swim long distances.

E) The dicynodonts could survive for periods of months aboard "rafts" of vegetation, few of which made their way to the northern hemisphere.

 

C) The dicynodonts were distributed more abundantly throughout Gondwanaland than throughout any other land mass.

252

59) If an increase in dicynodont species diversity (in other words, number of species) occurred soon after the Permian extinction, and if it occurred for the same general reason usually given for the increase in mammalian diversity following the Cretaceous extinction, then it should be attributed to

A) an innovation among the dicynodonts that allowed them to fill brand-new niches.

B) the availability of previously occupied niches.

C) the extinction of the dinosaurs (except the birds).

D) their outcompetition of many other terrestrial organisms.

 

B) the availability of previously occupied niches.

253

60) If the complex protein assemblage of the prokaryotic flagellum arose by the same general processes as those of the complex eyes of molluscs (such as squids and octopi), then

A) natural selection cannot account for the rise of the prokaryotic flagellum.

B) ancestral versions of this protein assemblage were either less functional or had different functions than modern prokaryotic flagella.

C) scientists should accept the conclusion that neither eyes nor flagella could have arisen by evolution.

D) we can conclude that both of these structures must have arisen through the direct action of an "intelligent designer."

 

B) ancestral versions of this protein assemblage were either less functional or had different functions than modern prokaryotic flagella.

254

61) Certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This evidence supports the claim that

A) some structures are so complex that natural selection cannot, and will not, explain their origins.

B) the power of natural selection allows it to act in an almost predictive fashion, producing organs that will be needed in future environments.

C) the motors of bacterial flagella were originally synthesized abiotically.

D) natural selection can produce new structures by coupling together parts of other structures.

E) bacteria that possess flagella must have lost the ability to pump certain chemicals across their plasma membranes.

 

D) natural selection can produce new structures by coupling together parts of other structures.

255

 

62) If these fly species lost the ability to fly independently of each other as a result of separate mutation events in each lineage, then the flightless condition in these species could be an example of

A) adaptive radiation.

B) species selection.

C) sexual selection.

D) allometric growth.

E) habitat differentiation.

 

B) species selection.

256

63) In each fly species, the entire body segment that gave rise to the original flight wings is missing. The mutation(s) that led to the flightless condition could have

A) duplicated all of the Hox genes in these flies' genomes.

B) altered the nucleotide sequence within a Hox gene.

C) altered the expression of a Hox gene.

D) all three of the above responses

E) two of the above answers are correct

 

E) two of the above answers are correct

257

64) 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 species W and Y

A) have genomes that are still similar enough for successful meiosis to occur in hybrid flies.

B) have more genetic similarity with each other than either did with the other two species.

C) may fuse into a single species if their hybrids remain fertile over the course of many generations.

D) Three of the above statements are correct.

E) Two of the statements above are correct.

 

D) Three of the above statements are correct.

258

65) Which of these fly organs, as they exist in current fly populations, best fits the description of an exaptation?

A) wings

B) balancing organs

C) mouthparts

D) thoraxes

E) walking appendages

 

B) balancing organs

259

66) The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Based on the information above, which explanation is most likely?

A) Pax-6 in all of these animals is not homologous; it arose independently in many different animal phyla due to intense selective pressure favoring vision.

B) The Pax-6 gene is really not "one" gene. It is many different genes that, over evolutionary time and due to convergence, have come to have a similar nucleotide sequence and function.

C) The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian period. Animals with eyes or eyespots are descendants of this ancestor.

D) The perfectly designed Pax-6 gene appeared instantaneously in all animals created to have eyes or eyespots.

C) The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian period. Animals with eyes or eyespots are descendants of this ancestor.

260

67) Fruit fly eyes are of the compound type, which is structurally very different from the camera-type eyes of mammals. Even the camera-type eyes of molluscs, such as octopi, are structurally quite different from those of mammals. Yet, fruit flies, octopi, and mammals possess very similar versions of Pax-6. The fact that the same gene helps produce very different types of eyes is most likely due to

A) the few differences in nucleotide sequence among the Pax-6 genes of these organisms.

B) variations in the number of Pax-6 genes among these organisms.

C) the independent evolution of this gene at many different times during animal evolution.

D) differences in the control of Pax-6 expression among these organisms.

D) differences in the control of Pax-6 expression among these organisms.

261

68) Pax-6 usually causes the production of a type of light-receptor pigment. In vertebrate eyes, though, a different gene (the rh gene family) is responsible for the light-receptor pigments of the retina. The rh gene, like Pax-6, is ancient. In the marine ragworm, for example, the rh gene causes production of c-opsin, which helps regulate the worm's biological clock. Which of these most likely accounts for vertebrate vision?

A) The Pax-6 gene mutated to become the rh gene among early mammals.

B) During vertebrate evolution, the rh gene for biological clock opsin was co-opted as a gene for visual receptor pigments.

C) In animals more ancient than ragworms, the rh gene(s) coded for visual receptor pigments; in lineages more recent than ragworms, rh has flip-flopped several times between producing biological clock opsins and visual receptor pigments.

D) Pax-6 was lost from the mammalian genome, and replaced by the rh gene much later.

B) During vertebrate evolution, the rh gene for biological clock opsin was co-opted as a gene for visual receptor pigments.

262

 

69) Fossilized stromatolites

A) all date from 2.7 billion years ago.

B) formed around deep-sea vents.

C) resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays.

D) provide evidence that plants moved onto land in the company of fungi around 500 million years ago.

E) contain the first undisputed fossils of eukaryotes and date from 2.1 billion years ago.

 

C) resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays

263

70) The oxygen revolution changed Earth's environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere?

A) the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules

B) the persistence of some animal groups in anaerobic habitats

C) the evolution of photosynthetic pigments that protected early algae from the corrosive effects of oxygen

D) the evolution of chloroplasts after early protists incorporated photosynthetic cyanobacteria

E) the evolution of multicellular eukaryotic colonies from communities of prokaryotes

 

A) the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules

264

71) Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?

A) The species have become separated by convergent evolution.

B) The climates of the two regions are similar.

C) India is in the process of separating from the rest of Asia.

D) Life in India was wiped out by ancient volcanic eruptions.

E) India was a separate continent until 45 million years ago.

 

E) India was a separate continent until 45 million years ago.

265

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

A) vacant ecological niches

B) genetic drift

C) colonization of an isolated region that contains suitable habitat and few competitor species

D) evolutionary innovation

E) an adaptive radiation in a group of organisms (such as plants) that another group uses as food

 

B) genetic drift

266

73) Which of the following steps has not yet been accomplished by scientists studying the origin of life?

A) synthesis of small RNA polymers by ribozymes

B) abiotic synthesis of polypeptides

C) formation of molecular aggregates with selectively permeable membranes

D) formation of protocells that use DNA to direct the polymerization of amino acids

E) abiotic synthesis of organic molecules

 

D) formation of protocells that use DNA to direct the polymerization of amino acids

267

74) A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of

A) the influence of environment on development.

B) paedomorphosis.

C) a change in a developmental gene or its regulation that altered the spatial organization of body parts.

D) heterochrony.

E) gene duplication.

 

C) a change in a developmental gene or its regulation that altered the spatial organization of body parts.

268

75) A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from lungs of an ancestral fish is an example of

A) an evolutionary trend.

B) exaptation.

C) changes in Hox gene expression.

D) paedomorphosis.

E) adaptive radiation.

 

B) exaptation.

269

 

1) The legless condition that is observed in several groups of extant reptiles is the result of

A) their common ancestor having been legless.

B) a shared adaptation to an arboreal (living in trees) lifestyle.

C) several instances of the legless condition arising independently of each other.

D) individual lizards adapting to a fossorial (living in burrows) lifestyle during their lifetimes.

 

C) several instances of the legless condition arising independently of each other.

270

2) The various taxonomic levels (namely, genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of

A) how widely the organisms assigned to each are distributed throughout the environment.

B) their inclusiveness.

C) the relative genome sizes of the organisms assigned to each.

D) morphological characters that are applicable to all organisms.

 

B) their inclusiveness.

271

3) If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of structural homology?

A) A and B

B) A and C

C) B and D

D) C and F

E) D and F

 

E) D and F

272

4) Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with

A) classifying organisms using the morphospecies concept.

B) the scientific discipline known as taxonomy.

C) phylogenies.

D) nested, ever-more inclusive categories of organisms.

E) a hierarchical classification scheme.

 

C) phylogenies.

273

5) Which of the following is (are) problematic when the goal is to construct phylogenies that accurately reflect evolutionary history?

A) polyphyletic taxa

B) paraphyletic taxa

C) monophyletic taxa

D) Two of the responses are correct.

 

D) Two of the responses are correct.

274

6) Which individual would make the worst systematist? One who is uncomfortable with the

A) Linnaean system of classification.

B) notion of hypothetical phylogenies.

C) PhyloCode method of classification.

D) notion of permanent polytomies.

 

B) notion of hypothetical phylogenies.

275

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

A) the legless condition found in various lineages of extant lizards

B) the five-digit condition of human hands and bat wings

C) the β hemoglobin genes of mice and of humans

D) the fur that covers Australian moles and North American moles

E) the bones of bat forelimbs and the bones of bird forelimbs

 

A) the legless condition found in various lineages of extant lizards

276

8) If, someday, an archaean cell is discovered whose rRNA sequence 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

A) homology.

B) homoplasy.

C) common ancestry.

D) retro-evolution by humans.

E) coevolution of humans and that archaean.

 

B) homoplasy.

277

9) The best classification system is that which most closely

A) unites organisms that possess similar morphologies.

B) conforms to traditional, Linnaean taxonomic practices.

C) reflects evolutionary history.

D) reflects the basic separation of prokaryotes from eukaryotes.

 

C) reflects evolutionary history.

278

10) Which of the following pairs are the best examples of homologous structures?

A) bones in the bat wing and bones in the human forelimb

B) owl wing and hornet wing

C) bat wing and bird wing

D) eyelessness in the Australian mole and eyelessness in the North American mole

 

A) bones in the bat wing and bones in the human forelimb

279

11) Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to

A) inheritance of acquired characteristics.

B) sexual selection.

C) inheritance of shared derived characters.

D) possession of analogous structures.

E) possession of shared primitive characters.

 

D) possession of analogous structures.

280

12) The importance of computers and of computer software to modern cladistics is most closely linked to advances in

A) light microscopy.

B) radiometric dating.

C) fossil discovery techniques.

D) Linnaean classification.

E) molecular genetics.

 

E) molecular genetics.

281

13) Which mutation should least require realignment of homologous regions of a gene that is common to several related species?

A) three-base insertion

B) one-base substitution

C) four-base insertion

D) one-base deletion

E) three-base deletion

 

B) one-base substitution

282

14) The common ancestors of birds and mammals were very early (stem) reptiles, 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

A) structural homologies.

B) vestiges.

C) homoplasies.

D) the result of shared ancestry.

E) molecular homologies.

 

C) homoplasies.

283

15) Which of the following is true of all horizontally oriented phylogenetic trees, where time advances to the right?

A) Each branch point represents a point in absolute time.

B) Organisms represented at the base of such trees are descendants of those represented at higher levels.

C) The fewer branch points that occur between two taxa, the more divergent their DNA sequences should be.

D) The common ancestor represented by the rightmost branch point existed more recently in time than the common ancestors represented at branch points located to the left.

E) The more branch points there are, the fewer taxa are likely to be represented.

 

D) The common ancestor represented by the rightmost branch point existed more recently in time than the common ancestors represented at branch points located to the left.

284

16) When using a cladistic approach to systematics, which of the following is considered most important for classification?

A) shared primitive characters

B) analogous primitive characters

C) shared derived characters

D) the number of homoplasies

E) overall phenotypic similarity

 

C) shared derived characters

285

17) Cladograms (a type of phylogenetic tree) constructed from evidence from molecular systematics are based on similarities in

A) morphology.

B) the pattern of embryological development.

C) biochemical pathways.

D) habitat and lifestyle choices.

E) mutations to homologous genes.

 

E) mutations to homologous genes.

286

18) There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then what can be properly said of hair?

A) It is a shared derived character of mammals, even if cynodonts continue to be classified as reptiles.

B) It is a shared derived character of the amniote clade, and not of the mammal clade.

C) It is a shared ancestral character of the amniote clade, but only if cynodonts are reclassified as mammals.

D) It is a shared derived character of the mammals, but only if cynodonts are reclassified as mammals.

 

D) It is a shared derived character of the mammals, but only if cynodonts are reclassified as mammals.

287

19) A researcher wants to determine the genetic relatedness of several breeds of dog (Canis lupus familiaris). The researcher should compare homologous sequences of this type of biochemical________which can be described as ________.

A) fatty acids; highly conserved

B) lipids; poorly conserved

C) proteins; highly conserved

D) amino acids; highly conserved

E) nucleic acids, poorly conserved

 

E) nucleic acids, poorly conserved

288

20) Concerning growth in genome size over evolutionary time, which of these is least associated with the others?

A) orthologous genes

B) gene duplications

C) paralogous genes

D) gene families

 

A) orthologous genes

289

 

21) Nucleic acid sequences that undergo few changes over the course of evolutionary time are said to be conserved. Conserved sequences of nucleic acids

A) are found in the most crucial portions of proteins.

B) include all mitochondrial DNA.

C) are abundant in ribosomes.

D) are proportionately more common in eukaryotic introns than in eukaryotic exons.

E) comprise a larger proportion of pre-mRNA (immature mRNA)

than of mature mRNA.

 

C) are abundant in ribosomes.

290

22) Species that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their

A) plasmids.

B) mitochondrial genomes.

C) homologous genes that are poorly conserved.

D) homologous genes that are highly conserved.

 

D) homologous genes that are highly conserved.

291

 

23) 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) that coding for ribosomal RNA

B) intronic DNA belonging to a gene whose product performs a crucial function

C) paralogous DNA that has lost its function (i.e., no longer codes for functional gene product)

D) mitochondrial DNA

E) exonic DNA that codes for a noncrucial part of a polypeptide

 

A) that coding for ribosomal RNA

292

24) A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of

A) archaeans and bacteria.

B) fungi and animals.

C) chimpanzees and humans.

D) sharks and dolphins.

E) mosses and ferns.

 

C) chimpanzees and humans.

293

25) The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma that have apparently undergone speciation from ancestral stock since the last glacial retreat about 10,000 years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species?

A) nuclear DNA

B) mitochondrial DNA

C) small nuclear RNA

D) ribosomal RNA

E) amino acids in proteins

 

B) mitochondrial DNA

294

26) 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?

A) Dogs and wolves have very similar morphologies.

B) Dogs and wolves belong to the same order.

C) Dogs and wolves are both members of the order Carnivora.

D) Dogs and wolves shared a common ancestor very recently.

 

D) Dogs and wolves shared a common ancestor very recently.

295

27) The reason that paralogous genes can diverge from each other within the same gene pool, whereas orthologous genes diverge only after gene pools are isolated from each other, is that

A) having multiple copies of genes is essential for the occurrence of sympatric speciation in the wild.

B) paralogous genes can occur only in diploid species; thus, they are absent from most prokaryotes.

C) polyploidy is a necessary precondition for the occurrence of sympatric speciation in the wild.

D) having an extra copy of a gene permits modifications to the copy without loss of the original gene product.

 

D) having an extra copy of a gene permits modifications to the copy without loss of the original gene product.

296

28) Paralogous genes that have lost the function of coding for any functional gene product are known as "pseudogenes." Which of these is a valid prediction regarding the fate of pseudogenes over evolutionary time?

A) They will be preserved by natural selection.

B) They will be highly conserved.

C) They will ultimately regain their original function.

D) They will be transformed into orthologous genes.

E) They will have relatively high mutation rates.

 

E) They will have relatively high mutation rates.

297

29) The most important feature that permits a gene to act as a molecular clock is

A) having a large number of base pairs.

B) having a larger proportion of exonic DNA than of intronic DNA.

C) having a reliable average rate of mutation.

D) its recent origin by a gene-duplication event.

E) its being acted upon by natural selection.

 

C) having a reliable average rate of mutation.

298

30) Neutral theory proposes that

A) molecular clocks are more reliable when the surrounding pH is close to 7.0.

B) most mutations of highly conserved DNA sequences should have no functional effect.

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) DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R groups) have a neutral electrical charge.

E) a significant proportion of mutations are not acted upon by natural selection.

 

E) a significant proportion of mutations are not acted upon by natural selection.

299

31) When it acts upon a gene, which of the following processes consequently makes that gene an accurate molecular clock?

A) transcription

B) directional natural selection

C) mutation

D) proofreading

E) reverse transcription

 

C) mutation

300

32) Which of these would, if it had acted upon a gene, prevent this gene from acting as a reliable molecular clock?

A) neutral mutations

B) genetic drift

C) mutations within introns

D) natural selection

E) most substitution mutations involving an exonic codon's third position

 

D) natural selection

301

33) 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) behavioral

C) nutritional

D) anatomical

E) ecological

 

A) molecular

302

34) What important criterion was used in the late 1960s to distinguish between the three multicellular eukaryotic kingdoms of the five-kingdom classification system?

A) the number of cells present in individual organisms

B) the geological stratum in which fossils first appear

C) the nutritional modes they employ

D) the biogeographic province where each first appears

E) the features of their embryos

 

C) the nutritional modes they employ

303

35) Members of which kingdom have cell walls and are all heterotrophic?

A) Plantae

B) Fungi

C) Animalia

D) Protista

E) Monera

 

B) Fungi

304

36) Which kingdom has been replaced with two domains?

A) Plantae

B) Fungi

C) Animalia

D) Protista

E) Monera

 

E) Monera

305

 

37) Which eukaryotic kingdom is polyphyletic, and therefore unacceptable, based on cladistics?

A) Plantae

B) Fungi

C) Animalia

D) Protista

E) Monera

 

D) Protista

306

38) Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient proteobacterium and an ancient cyanobacterium?

A) Plantae

B) Fungi

C) Animalia

D) Protista

E) Monera

 

A) Plantae

307

 

39) A large proportion of archaeans are extremophiles, so called because they inhabit extreme environments with high acidity, salinity, and/or temperature. Such environments are thought to have been much more common on the primitive Earth. Thus, modern extremophiles survive only in places that their ancestors became adapted to long ago. Which of the following is, consequently, a valid statement about modern extremophiles, assuming that their habitats have remained relatively unchanged?

A) Among themselves, they should share relatively few ancestral traits, especially those that enabled ancestral forms to adapt to extreme conditions.

B) On a phylogenetic tree whose branch lengths are proportional to the amount of genetic change, the branches of the extremophiles should be shorter than the non-extremophilic archaeans.

C) They should contain genes that originated in eukaryotes that are the hosts for numerous species of bacteria.

D) They should currently be undergoing a high level of horizontal gene transfer with non-extremophilic archaeans.

 

B) On a phylogenetic tree whose branch lengths are proportional to the amount of genetic change, the branches of the extremophiles should be shorter than the non-extremophilic archaeans.

308

40) Which extinct species should be the best candidate to serve as the outgroup for the clade whose common ancestor occurs at position 2 in Figure 26.1?

A) A

B) B

C) C

D) D

E) E

 

A) A

309

41) If Figure 26.1 is an accurate depiction of relatedness, then which of the following should be correct?

1.     The entire tree is based on maximum parsimony.

2.     If all species depicted here make up a taxon, this taxon is monophyletic.

3.     The last common ancestor of species B and C occurred more recently than the last common     ancestor of species D and E.

4.     Species A is the direct ancestor of both species B and species C.

5.     The species present at position 3 is ancestral to C, D, and E.

A) 1 and 3

B) 3 and 4

C) 2, 3, and 4

D) 1, 2, and 3

 

D) 1, 2, and 3

310

 

42) Placing whales and hippos in the same clade means

A) that these organisms are phenotypically more similar to each other than to any others shown on the trees in Figure 26.2.

B) that their morphological similarities are probably homoplasies.

C) that they had a common ancestor.

D) that all three of the responses are correct.

E) that two of the responses are correct.

 

C) that they had a common ancestor.

311

 

43) If it turns out that the whale lineage diverged from the lineage leading to hippos after the divergence of the lineage leading to the pigs and other artiodactyls, and if the whales continue to be classified in the order Cetacea, then what becomes true of the order Artiodactyla?

A) It becomes monophyletic.

B) It becomes paraphyletic.

C) It becomes polyphyletic.

D) It is incorporated into the order Cetacea.

 

B) It becomes paraphyletic.

312

44) If it turns out that the whale lineage diverged from the lineage leading to hippos after the divergence of the lineage leading to the pigs and other artiodactyls, and if the whales continue to be classified in the order Cetacea, then what becomes true of the taxon Cetartiodactyla?

A) It should be considered as one monophyletic order.

B) It should be considered a superorder that consists of two monophyletic orders.

C) It should be established as a paraphyletic order.

D) It should be thrown out or modified by taxonomists if classification is to reflect evolutionary history

 

A) It should be considered as one monophyletic order.

313

45) One morphological feature of modern cetaceans is a vestigial pelvic girdle. If it is determined that cetacean lineage diverged from the artiodactyls' lineage after the divergence of pigs and other artiodactyla, then what should be true of the vestigial pelvic girdle of cetaceans?

A) It should be considered a shared ancestral character of the cetartiodactyls.

B) It should be considered a shared derived character of the cetartiodactyls.

C) It should be considered a shared ancestral character of the cetaceans.

D) It should be considered a shared derived character of the cetaceans.

 

D) It should be considered a shared derived character of the cetaceans.

314

46) If cetaceans are determined to have diverged from the lineage leading to the artiodactyls before the divergence of lineages leading to the modern artiodactyls (including hippos), then the cetaceans can be considered

1.     a sister order to the order Artiodactyla.

2.     an ingroup of the order Artiodactyla.

3.     the common ancestor of the order Artiodactyla.

A) 1 only

B) 3 only

C) 1 and 2

D) 1 and 3

E) 2 and 3

 

A) 1 only

315

47) It was once thought that cetaceans had evolved from an extinct group of mammals called the mesonychids. If, in the future, it is determined that some organisms currently classified as cetaceans did actually evolve from mesonychids, whereas other cetaceans evolved from artiodactyl stock, then what will be true of the order Cetacea?

A) It will be paraphyletic.

B) It will be polyphyletic.

C) It will need to be thrown out or modified if classification is to reflect evolutionary history.

D) Two of the responses are correct.

 

D) Two of the responses are correct.

316

48) What can be properly inferred from Figure 26.2?

A) In the "Without" tree, pigs are more distantly related to hippos than is depicted in the "Within" tree.

B) In the "Without" tree, pigs are more closely related to hippos than are whales.

C) In the "Within" tree, pigs are more closely related to whales than they are to hippos.

D) The "Without" tree is more consistent with molecular evidence than is the "Within" tree.

E) In the "Within" tree, all artiodactyls, including hippos, are more closely related to each other than any are to the whales.

 

B) In the "Without" tree, pigs are more closely related to hippos than are whales.

317

 

49) If the sequence of species A in Figure 26.3 differs from that of the other four species due to simple misalignment, then what should the computer software find when it compares the sequence of species A to those of the other four species?

A) The nucleotide at position 1 should be different in species A, but the same in species BE.

B) The nucleotide sequence of species A should have long sequences that are nearly identical to those of the other species, but offset in terms of position number.

C) The sequences of species BE, though different from that of species A, should be identical to each other, without exception.

D) If the software compares the amino acid sequence of the actual protein product rather than the nucleotide sequence, then the amino acid sequences of species BE should be similar to each other, but very different from that of species A.

E) Computer software is useless in determining sequences of introns; it can only be used with exons

 

B) The nucleotide sequence of species A should have long sequences that are nearly identical to those of the other species, but offset in terms of position number.

318

50) Which of the following items does not necessarily exist in a simple linear relationship with the number of gene-duplication events when placed as the label on the vertical axis of the following graph?

A) number of genes

B) number of DNA base pairs

C) genome size

D) mass (in picograms) of DNA

E) phenotypic complexity

 

E) phenotypic complexity

319


 

51) If the early history of life on Earth is accurately depicted by Figure 26.4, then which statement is least in agreement with the hypothesis proposed by this tree?

A) The last universal common ancestor of all extant species is better described as a community of organisms, rather than an individual species.

B) The origin of the three domains appears as a polytomy.

C) Archaean genomes should contain genes that originated in bacteria, and vice versa.

D) Eukaryotes are more closely related to archaeans than to bacteria.

 

D) Eukaryotes are more closely related to archaeans than to bacteria.

320

 

52) Which of these processes can be included among those responsible for the horizontal components of Figure 26.4?

A) endosymbiosis

B) mitosis

C) binary fission

D) point mutations

E) S phase of the cell cycle

 

A) endosymbiosis

321

53) Which portion of Figure 26.4 may ultimately be better depicted as a "ring"?

A) the bacterial lineage

B) the archaean lineage

C) the eukaryotic lineage

D) the trunk of the tree

E) the part corresponding to the first living cell on Earth

 

D) the trunk of the tree

322

54) The great apes comprise the family Hominidae, whereas the lesser apes comprise the family Hylobatidae. If the extant organisms on the far right side of Figure 26.5 comprise the next-most exclusive (i.e., specific) taxon, then they comprise different

A) subspecies.

B) species.

C) genuses.

D) genera.

E) orders.

 

D) genera.

323

55) Together, the lesser apes and great apes shared a common ancestor most recently with other members of their

A) order.

B) class.

C) subclass.

D) subfamily.

E) family.

 

A) order.

324

56) From Figure 26.5, to which of the extant apes are orangutans most closely related?

A) gibbons and siamangs

B) Dryopithecus and Ouranopithecus

C) gorillas

D) chimps

E) chimps, gorillas, and humans

 

E) chimps, gorillas, and humans

325

57) Assuming chimps and gorillas are humans' closest relatives, removing humans from the great ape clade and placing them in a different clade has the effect of making the phylogenetic tree of the great apes

A) polyphyletic.

B) paraphyletic.

C) monophyletic.

D) conform with Linnaeus' view of great ape phylogeny.

 

B) paraphyletic.

326

58) What is true of the phylogeny in Figure 26.5?

1.    It is rooted.

2.     The gibbons and siamangs represent an outgroup of the great apes.

3.     Chimps and humans are the closest extant sister taxa depicted here.

4.     It is absolute, meaning free of error.

5.     The last common ancestor of the great apes lived about 14 million years ago.

A) 1, 2, and 3

B) 1, 2, and 5

C) 1, 2, 3, and 4

D) 1, 2, 3, and 5

E) 2, 3, 4, and 5

 

D) 1, 2, 3, and 5

327

59) From Figure 26.5, what is true of Dryopithecus and Ouranopithecus?

1.     They were great apes.

2.     They shared a common ancestor more recently with the orangutans than with the other great apes.

3.     They appear to be part of a polytomy.

4.     Their closest common ancestor with all of the extant great apes is the one they share with the orangutans.

5.     They were about as different from each other genetically as humans are different from chimps.

A) 1, 2, and 4

B) 1, 3, and 4

C) 2, 4, and 5

D) 1, 2, 3, and 4

E) 2, 3, 4, and 5

 

B) 1, 3, and 4

328

60) From Figure 26.5, which other event occurred closest in time to the divergence of gorillas from the lineage that led to humans and chimps?

A) the divergence of chimps and humans

B) the divergence of Dryopithecus and Ouranopithecus

C) the divergence of gibbons and siamangs

D) could be either the divergence of chimps and humans OR of Dryopithecus and Ouranopithecus

E) could be either the divergence of chimps and humans OR of gibbons and siamangs

 

E) could be either the divergence of chimps and humans OR of gibbons and siamangs

329

61) Which of these can be properly inferred from the phylogeny in Figure 26.5?

A) Chimps and humans evolved from gorillas.

B) The lesser apes are genetically more distinct from each other than the members of the great apes are from each other.

C) Orangutans have existed for about 14 million years.

D) Chimps and humans should share more homoplasies than should chimps and gorillas.

E) Together, the lesser apes and great apes form a clade.

 

E) Together, the lesser apes and great apes form a clade.

330

 

62) Taxonomically, what should be done with the birds?

A) The traditional stance is correct. Such dramatic morphological change as undergone by birds merits that the birds be placed in their own order, separate from the reptiles.

B) The birds should be reclassified, and their new taxon should be the subclass Aves. Genetic similarity trumps morphological dissimilarity.

C) The rest of the reptiles should be reclassified as a subclass within the class Aves.

D) Science is consensual. Taxonomy is a science. Variant classification schemes involving the birds should be tolerated until consensus is reached.

 

D) Science is consensual. Taxonomy is a science. Variant classification schemes involving the birds should be tolerated until consensus is reached.

331

63) Traditional zoologists have long agreed that birds evolved from dinosaurs. What keeps such zoologists from agreeing that birds, like dinosaurs, should be considered reptiles?

A) There is not yet enough evidence to be sure.

B) Stubbornness, insofar as they are unwilling to change their thinking when new data warrants it.

C) They deny the validity of genetic molecular data.

D) They differ in what they consider to be important traits for assigning organisms to the class Reptilia

 

D) They differ in what they consider to be important traits for assigning organisms to the class Reptilia

332

64) For a proponent of PhyloCode classification, what is true of the reptile clade if birds are not included in it?

A) It becomes paraphyletic and, thus, an invalid reflection of evolutionary history.

B) It becomes a subclass, instead of a class.

C) It becomes a superclass, whereas the birds remain a class.

D) PhyloCode does not concern itself with what is, or is not, a clade.

 

A) It becomes paraphyletic and, thus, an invalid reflection of evolutionary history.

333

65) Based on the tabular data, and assuming that time advances vertically, which cladogram (a type of phylogenetic tree) is the most likely depiction of the evolutionary relationships among these five species?

 

    

 

 

Answer:  D

334

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

A) It is the most-upstream exon of this gene.

B) Due to alternative gene splicing, this exon is often treated as an intron.

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

D) These five species must actually constitute a single species.

E) This exon is rich in G-C base pairs; thus, it is more stable.

 

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

335

67) Regarding these sequence homology data, the principle of maximum parsimony would be applicable in

A) distinguishing introns from exons.

B) determining degree of sequence homology.

C) selecting appropriate genes for comparison among species.

D) inferring evolutionary relatedness from the number of sequence differences.

 

D) inferring evolutionary relatedness from the number of sequence differences.

336

 

68) 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?

A) Intron I

B) Exon I

C) Intron VI

D) Exon V

 

C) Intron VI

337

69) Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up

A) a valid taxon.

B) a monophyletic clade.

C) an ingroup, with species U as the outgroup.

D) a paraphyletic group.

E) a polyphyletic group.

 

D) a paraphyletic group.

338

70) In a comparison of birds and mammals, having four limbs is

A) a shared ancestral character.

B) a shared derived character.

C) a character useful for distinguishing birds from mammals.

D) an example of analogy rather than homology.

E) a character useful for sorting bird species.

 

A) a shared ancestral character.

339

71) To apply parsimony to constructing a phylogenetic tree,

A) choose the tree that assumes all evolutionary changes are equally probable.

B) choose the tree in which the branch points are based on as many shared derived characters as possible.

C) base phylogenetic trees only on the fossil record, as this provides the simplest explanation for evolution.

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

E) choose the tree with the fewest branch points.

 

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

340

 

72) Based on this tree, which statement is not correct?

A) The salamander lineage is a basal taxon.

B) Salamanders are a sister group to the group containing lizards, goats, and humans.

C) Salamanders are as closely related to goats as to humans.

D) Lizards are more closely related to salamanders than to humans

 

D) Lizards are more closely related to salamanders than to humans

341

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

A) lion

B) domestic cat

C) wolf

D) leopard

E) tiger

 

C) wolf

342

 

1) Mycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which statement concerning mycoplasmas should be true?

A) They are gram-negative.

B) They are subject to lysis in hypotonic conditions.

C) They lack a cell membrane as well.

D) They should contain less cellulose than do bacteria that possess cell walls.

E) They possess typical prokaryotic flagella.

 

B) They are subject to lysis in hypotonic conditions.

343

2) Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available?

A) Some closely resemble animals, which lack cell walls.

B) Their cell walls are composed of very different biochemicals.

C) Some have cell walls only for support.

D) Some have cell walls only for protection from herbivores.

E) Some have cell walls only to control osmotic balance.

 

B) Their cell walls are composed of very different biochemicals.

344

 

3) Which statement about bacterial cell walls is false?

A) Bacterial cell walls differ in molecular composition from plant cell walls.

B) Cell walls prevent cells from bursting in hypotonic environments.

C) Cell walls prevent cells from dying in hypertonic conditions.

D) Bacterial cell walls are similar in function to the cell walls of many protists, fungi, and plants.

E) Cell walls provide the cell with a degree of physical protection from the environment.

 

C) Cell walls prevent cells from dying in hypertonic conditions.

345

4) The predatory bacterium, Bdellovibrio bacteriophorus, drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm?

1.     membrane composed mostly of lipopolysaccharide

2.     membrane composed mostly of phospholipids

3.     peptidoglycan

4.     capsule

A) 2, 4, 3, 1

B) 1, 3, 4, 2

C) 1, 4, 3, 2

D) 4, 1, 3, 2

E) 4, 3, 1, 2

 

D) 4, 1, 3, 2

346

5) Jams, jellies, preserves, honey, and other foodstuffs with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment

A) undergo death by plasmolysis.

B) are unable to metabolize the glucose or fructose, and thus starve to death.

C) experience lysis.

D) are obligate anaerobes.

E) are unable to swim through these thick and viscous materials.

 

A) undergo death by plasmolysis.

347

6) In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures?

1.     nucleoid region

2.     endospore

3.     fimbriae

4.     plasmids

A) 1 only

B) 1 and 2 only

C) 1 and 4 only

D) 2 and 4 only

E) 1, 2, and 4

 

E) 1, 2, and 4

348

7) Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces?

1.     capsules

2.     endospores

3.     fimbriae

4.     plasmids

5.     flagella

A) 1 and 2

B) 1 and 3

C) 2 and 3

D) 3 and 4

E) 3 and 5

 

B) 1 and 3

349

8) The typical prokaryotic flagellum features

A) an internal 9 + 2 pattern of microtubules.

B) an external covering provided by the plasma membrane.

C) a complex "motor" embedded in the cell wall and plasma membrane.

D) a basal body that is similar in structure to the cell's centrioles.

E) a membrane-enclosed organelle with motor proteins.

 

C) a complex "motor" embedded in the cell wall and plasma membrane.

350

9) Prokaryotic ribosomes differ from those present in eukaryotic cytosol. Because of this, which of the following is correct?

A) Some antibiotics can block protein synthesis in bacteria without effects in the eukaryotic host.

B) Eukaryotes did not evolve from prokaryotes.

C) Translation can occur at the same time as transcription in eukaryotes but not in prokaryotes.

D) Some antibiotics can block the synthesis of peptidoglycan in the walls of bacteria.

E) Prokaryotes are able to use a much greater variety of molecules as food sources than can eukaryotes.

 

A) Some antibiotics can block protein synthesis in bacteria without effects in the eukaryotic host.

351

10) Which statement about the genomes of prokaryotes is correct?

A) Prokaryotic genomes are diploid throughout most of the cell cycle.

B) Prokaryotic chromosomes are sometimes called plasmids.

C) Prokaryotic cells have multiple chromosomes, "packed" with a relatively large amount of protein.

D) The prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleolus.

E) Prokaryotic genomes are composed of circular DNA.

 

E) Prokaryotic genomes are composed of circular DNA.

352

11) If a bacterium regenerates from an endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably also

A) lack antibiotic-resistant genes.

B) lack a cell wall.

C) lack a chromosome.

D) lack water in its cytoplasm.

E) be unable to survive in its normal environment.

 

A) lack antibiotic-resistant genes.

353

12) Although not present in all bacteria, this cell covering often enables cells that possess it to resist the defenses of host organisms, especially their phagocytic cells.

A) endospore

B) sex pilus

C) cell wall

D) capsule

 

D) capsule

354

13) Prokaryotes' essential genetic information is located in the

A) nucleolus.

B) nucleoid.

C) nucleosome.

D) plasmids.

E) exospore.

 

B) nucleoid.

355

14) Which of the following is an important source of endotoxin in gram-negative species?

A) endospore

B) sex pilus

C) flagellum

D) cell wall

E) capsule

 

D) cell wall

356

15) Chloramphenicol is an antibiotic that targets prokaryotic (70S) ribosomes, but not eukaryotic (80S) ribosomes. Which of these questions stems from this observation, plus an understanding of eukaryotic origins?

A) Can chloramphenicol also be used to control human diseases that are caused by archaeans?

B) Can chloramphenicol pass through the capsules possessed by many cyanobacteria?

C) If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes?

D) Why aren't prokaryotic ribosomes identical to eukaryotic ribosomes?

E) How is translation affected in ribosomes that are targeted by chloramphenicol?

 

C) If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes?

357

16) In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid, then the result should be

A) a bacterium that has undergone transduction.

B) the rapid spread of tetracycline resistance to other bacteria in that habitat.

C) the subsequent loss of tetracycline resistance from this bacterium.

D) the production of endospores among the bacterium's progeny.

E) the temporary possession by this bacterium of a completely diploid genome.

 

B) the rapid spread of tetracycline resistance to other bacteria in that habitat.

358

17) Regarding prokaryotic genetics, which statement is correct?

A) Crossing over during prophase I introduces some genetic variation.

B) Prokaryotes feature the union of haploid gametes, as do eukaryotes.

C) Prokaryotes exchange some of their genes by conjugation, the union of haploid gametes, and transduction.

D) Mutation is a primary source of variation in prokaryote populations.

E) Prokaryotes skip sexual life cycles because their life cycle is too short.

 

D) Mutation is a primary source of variation in prokaryote populations.

359

 

18) Which of these statements about prokaryotes is correct?

A) Bacterial cells conjugate to mutually exchange genetic material.

B) Their genetic material is confined within vesicles known as plasmids.

C) They divide by binary fission, without mitosis or meiosis.

D) The persistence of bacteria throughout evolutionary time is due to their genetic homogeneity (in other words, sameness).

E) Genetic variation in bacteria is not known to occur, because of their asexual mode of reproduction.

 

C) They divide by binary fission, without mitosis or meiosis.

360

19) Which of the following is least associated with the others?

A) horizontal gene transfer

B) genetic recombination

C) conjugation

D) transformation

E) binary fission

 

E) binary fission

361

20) In Fred Griffith's experiments, harmless R strain pneumococcus became lethal S strain pneumococcus as the result of which of the following?

1.     horizontal gene transfer

2.     transduction

3.     conjugation

4.     transformation

5.     genetic recombination

A) 2 only

B) 4 only

C) 2 and 5

D) 1, 3, and 5

E) 1, 4, and 5

 

E) 1, 4, and 5

362

21) Hershey and Chase performed an elegant experiment that convinced most biologists that DNA, rather than protein, was the genetic material. This experiment subjected bacteria to the same gene transfer mechanism as occurs in

A) transduction.

B) transformation.

C) conjugation.

D) binary fission.

E) endosymbiosis.

 

A) transduction.

363

22) Match the numbered terms to the description that follows. Choose all appropriate terms.

1.     autotroph

2.     heterotroph

3.     phototroph

4.     chemotroph

a prokaryote that obtains both energy and carbon as it decomposes dead organisms

A) 1 only

B) 4 only

C) 1 and 3

D) 2 and 4

E) 1, 3, and 4

 

D) 2 and 4

364

23) Match the numbered terms to the description that follows. Choose all appropriate terms.

1.     autotroph

2.     heterotroph

3.     phototroph

4.     chemotroph

an organism that obtains both carbon and energy by ingesting prey

A) 1 only

B) 4 only

C) 1 and 3

D) 2 and 4

E) 1, 3, and 4

 

D) 2 and 4

365

24) Match the numbered terms to the description that follows. Choose all appropriate terms.

1.     autotroph

2.     heterotroph

3.     phototroph

4.     chemotroph

an organism that relies on photons to excite electrons within its membranes

A) 1 only

B) 3 only

C) 1 and 3

D) 2 and 4

E) 1, 3, and 4

 

B) 3 only

366

25) Which of the following obtain energy by oxidizing inorganic substancesenergy that is used, in part, to fix CO2?

A) photoautotrophs

B) photoheterotrophs

C) chemoautotrophs

D) chemoheterotrophs that perform decomposition

E) parasitic chemoheterotrophs

 

C) chemoautotrophs

367

26) Mitochondria are thought to be the descendants of certain alpha proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosome have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

A) plasmolysis

B) conjugation

C) translation

D) endocytosis

E) horizontal gene transfer

 

E) horizontal gene transfer

368

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

A) microscopic examination of staining characteristics of the cell wall

B) metabolic characteristics such as the production of methane gas

C) metabolic characteristics such as chemoautotrophy and photosynthesis

D) genetic characteristics such as ribosomal RNA sequences

E) ecological characteristics such as the ability to survive in extreme environments

 

D) genetic characteristics such as ribosomal RNA sequences

369

 

28) Which statement about the domain Archaea is true?

A) Genetic prospecting has recently revealed the existence of many previously unknown archaean species.

B) No archaeans can reduce CO2 to methane.

C) The genomes of archaeans are unique, containing no genes that originated within bacteria.

D) No archaeans can inhabit solutions that are nearly 30% salt.

E) No archaeans are adapted to waters with temperatures above the boiling point.

 

A) Genetic prospecting has recently revealed the existence of many previously unknown archaean species.

370

29) If archaeans are more closely related to eukaryotes than to bacteria, then which of the following is a reasonable prediction?

A) Archaean DNA should have no introns.

B) Archaean chromosomes should have no protein bonded to them.

C) Archaean DNA should be single-stranded.

D) Archaean ribosomes should be larger than typical prokaryotic ribosomes.

E) Archaeans should lack cell walls.

 

D) Archaean ribosomes should be larger than typical prokaryotic ribosomes.

371

30) Which of the following traits do archaeans and bacteria share?

1.     composition of the cell wall

2.     presence of plasma membrane

3.     lack of a nuclear envelope

4.     identical rRNA sequences

A) 1 only

B) 3 only

C) 1 and 3

D) 2 and 3

E) 2 and 4

 

D) 2 and 3

372

 

31) Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

A) extreme halophiles

B) extreme thermophiles

C) methanogens

D) cyanobacteria

E) nitrogen-fixing bacteria that live in root nodules

 

A) extreme halophiles

373

32) The thermoacidophile, Sulfolobus acidocaldarius, lacks peptidoglycan, but still possesses a cell wall. What is likely to be true of this species?

1.     It is a bacterium.

2.     It is an archaean.

3.     The optimal pH of its enzymes will lie above pH 7.

4.     The optimal pH of its enzymes will lie below pH 7.

5.     It could inhabit certain hydrothermal springs.

6.     It could inhabit alkaline hot springs.

A) 1, 3, and 6

B) 2, 4, and 6

C) 2, 4, and 5

D) 1, 3, and 5

E) 1, 4, and 5

 

C) 2, 4, and 5

374

33) A fish that has been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile, Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would support your suspicion?

1.     the presence of the same photosynthetic pigments found in cyanobacteria

2.     cell walls that lack peptidoglycan

3.     cells that are isotonic to conditions on the surface of the fish

4.     cells containing bacteriorhodopsin

5.     the presence of very large numbers of ion pumps in its plasma membrane

A) 2 and 5

B) 3 and 4

C) 1, 4, and 5

D) 3, 4, and 5

E) 2, 3, 4, and 5

 

E) 2, 3, 4, and 5

375

34) The termite gut protist, Mixotricha paradoxa, has at least two kinds of bacteria attached to its outer surface. One kind is a spirochete that propels its host through the termite gut. A second type of bacteria synthesizes ATP, some of which is used by the spirochetes. The locomotion provided by the spirochetes introduces the ATP-producing bacteria to new food sources. Which term(s) is (are) applicable to the relationship between the two kinds of bacteria?

1.     mutualism

2.     parasitism

3.     symbiosis

4.     metabolic cooperation

A) 1 only

B) 1 and 2

C) 2 and 3

D) 1, 3, and 4

E) 2, 3, and 4

 

D) 1, 3, and 4

376

 

35) In general, what is the primary ecological role of prokaryotes?

A) parasitizing eukaryotes, thus causing diseases

B) breaking down organic matter

C) metabolizing materials in extreme environments

D) adding methane to the atmosphere

E) serving as primary producers in terrestrial environments

 

B) breaking down organic matter

377

36) If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?

A) The number of organisms on Earth would decrease by 1020%.

B) Human populations would thrive in the absence of disease.

C) Bacteriophage numbers would dramatically increase.

D) The recycling of nutrients would be greatly reduced, at least initially.

E) There would be no more pathogens on Earth.

 

D) The recycling of nutrients would be greatly reduced, at least initially.

378

37) In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf's nonliving, waxy covering while inhibiting the growth of other microbes that are plant pathogens. If this bacterium gains access to the inside of a leaf, however, it causes a fatal disease in the plant. Once the plant dies, the bacterium and its offspring decompose the plant. What is the correct sequence of ecological roles played by the bacterium in the situation described here? Use only those that apply.

1.     nutrient recycler

2.     mutualist

3.     commensal

4.    parasite

5.     primary producer

A) 1, 3, 4

B) 2, 3, 4

C) 2, 4, 1

D) 1, 2, 5

E) 1, 2, 3

 

C) 2, 4, 1

379

 

38) Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth?

A) Refrigeration: slows bacterial metabolism and growth.

B) Closing previously opened containers: prevents more bacteria from entering, and excludes O2.

C) Pickling: creates a pH at which most bacterial enzymes cannot function.

D) Canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells.

E) Irradiation: kills bacteria by mutating their DNA to such an extent that their DNA-repair enzymes are overwhelmed.

 

B) Closing previously opened containers: prevents more bacteria from entering, and excludes O2.

380

39) 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

A) unable to fix carbon dioxide.

B) antibiotic resistant.

C) unable to fix nitrogen.

D) unable to synthesize peptidoglycan.

E) deficient in certain vitamins and nutrients.

 

E) deficient in certain vitamins and nutrients.

381

40) Which term best describes what has occurred among the experimental populations of cells over this eight-year period?

A) microevolution

B) speciation

C) adaptive radiation

D) sexual selection

E) stabilizing selection

 

A) microevolution

382

41) Which of the following, if it occurs in the absence of any other type of adaptation listed here, is least reasonable in terms of promoting bacterial survival over evolutionary time in a low-glucose environment?

A) increased efficiency at transporting glucose into the cell from the environment

B) increased ability to survive on simple sugars, other than glucose

C) increased ability to synthesize glucose from amino acid precursors

D) increased reliance on glycolytic enzymes

E) increased sensitivity to, and ability to move toward, whatever glucose is present in its habitat

 

D) increased reliance on glycolytic enzymes

383

42) If the vertical axis of Figure 27.1 refers to "Darwinian fitness," then which of the following is the most valid and accurate measure of fitness?

A) number of daughter cells produced per mother cell per generation

B) amount of ATP generated per cell per unit time

C) average swimming speed of cells through the growth medium

D) amount of glucose synthesized per unit time

E) number of generations per unit time

 

E) number of generations per unit time

384

43) If new genetic variation in the experimental populations arose solely by spontaneous mutations, then the most effective process for subsequently increasing the prevalence of the beneficial mutations in the population over the course of generations is

A) transduction.

B) binary fission.

C) conjugation.

D) transformation.

E) meiosis.

 

B) binary fission.

385

44) E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, what should be true of E. coli's generation time (especially early in the course of the experiment, but less so later on)?

A) Generation time should be the same as in the typical environment.

B) Generation time should be faster than in the typical environment.

C) Generation time should be slower than in the typical environment.

D) It is theoretically impossible to make any predictions about generation time under these conditions.

 

C) Generation time should be slower than in the typical environment.

386

 

45) If the experimental population of E. coli lacks an F factor or F plasmid, and if bacteriophages are excluded from the bacterial cultures, then which of these is (are) means by which beneficial mutations might be transmitted horizontally to other E. coli cells?

A) via sex pili

B) via transduction

C) via conjugation

D) via transformation

E) Two of the responses above are correct.

 

D) via transformation

387

46) What is occurring at Time C that is decreasing the DNA content?

A) crossing over

B) cytokinesis

C) meiosis

D) degradation of DNA that was not retained in the recipient's chromosome

E) reversal of the direction of conjugation

 

D) degradation of DNA that was not retained in the recipient's chromosome

388

47) How is the recipient cell different at Time D than it was at Time A?

A) It has a greater number of genes.

B) It has a greater mass of DNA.

C) It has a different sequence of base pairs.

D) It contains bacteriophage DNA.

E) Its membrane-bound DNA pumps are inactive.

 

C) It has a different sequence of base pairs.

389

48) Which two processes are responsible for the shape of the curve at Time B?

1.     transduction

2.     entry of single-stranded Hfr DNA

3.     rolling circle replication of single-stranded Hfr DNA

4.     activation of DNA pumps in plasma membrane

A) 1 and 2

B) 1 and 4

C) 2 and 3

D) 2 and 4

E) 3 and 4

 

C) 2 and 3

390

49) During which two times can the recipient accurately be described as "recombinant" due to the sequence of events portrayed in Figure 27.2?

A) during Times C and D

B) during Times A and C

C) during Times B and C

D) during Times A and B

E) during Times B and D

 

A) during Times C and D

391

50) Which question, arising from the results depicted in Figure 27.2, is most interesting from a genetic perspective, and has the greatest potential to increase our knowledge base?

A) If reciprocal crossing over could occur even if the piece of donated Hfr DNA is identical to the homologous portion of the recipient's chromosome, what prevents this from occurring?

B) What forces are generally responsible for disrupting the sex pilus?

C) How is it that a recipient cell does not necessarily become an Hfr cell as the result of conjugation with an Hfr cell?

D) What makes a cell an Hfr cell?

 

A) If reciprocal crossing over could occur even if the piece of donated Hfr DNA is identical to the homologous portion of the recipient's chromosome, what prevents this from occurring?

392

51) The data were collected from the heterocysts of a nitrogen-fixing cyanobacterium inhabiting equatorial ponds. Study the following graph and choose the most likely explanation for the shape of the curve.

A) Enough O2 enters heterocysts during hours of peak photosynthesis to have a somewhat-inhibitory effect on nitrogen fixation.

B) Light-dependent reaction rates must be highest between 1800 hours and 0600 hours.

C) Atmospheric N2 levels increase at night because plants are no longer metabolizing this gas, so they are not absorbing this gas through their stomata.

D) Heterocyst walls become less permeable to N2 influx during darkness.

E) The amount of fixed nitrogen that is dissolved in the pond water in which the cyanobacteria are growing peaks at the close of the photosynthetic day (1800 hours).

 

A) Enough O2 enters heterocysts during hours of peak photosynthesis to have a somewhat-inhibitory effect on nitrogen fixation.

393


52) Consider the thermoacidophile, Sulfolobus acidocaldarius. Which of the following graphs most accurately depicts the expected temperature and pH profiles of its enzymes? (Note: The horizontal axes of these graphs are double, with pH above and temperature below.)

A

394

53) This bacterium's ability to survive in a human who is taking penicillin pills may be due to the presence of

1.     penicillin-resistance genes

2.     a secretory system that removes penicillin from the cell

3.     a gram-positive cell wall

4.     a gram-negative cell wall

5.     an endospore

A) 1 or 5

B) 2 or 3

C) 4 or 5

D) 2, 3, or 5

E) 2, 4, or 5

 

D) 2, 3, or 5

395

 

54) Adherence to the intestinal lining by this bacterium is due to its possession of

A) fimbriae.

B) pili.

C) a capsule.

D) a flagellum.

E) a cell wall with an outer lipopolysaccharide membrane.

 

C) a capsule.

396

55) What should be true of the cell wall of this bacterium?

A) Its innermost layer is composed of a phospholipid bilayer.

B) After it has been subjected to Gram staining, the cell should remain purple.

C) It has an outer membrane of lipopolysaccharide.

D) It is mostly composed of a complex, cross-linked polysaccharide.

E) Two of the responses above are correct.

 

C) It has an outer membrane of lipopolysaccharide.

397

56) Some of the proteins that allow this bacterium to swim are related (in an evolutionary sense) to proteins that

A) attach to the single chromosome.

B) act as restriction enzymes.

C) synthesize peptidoglycan for the cell wall.

D) move penicillin out of the cell.

E) comprise its ribosomes.

 

D) move penicillin out of the cell.

398

57) In which feature(s) should one be able to locate a complete chromosome of this bacterium?

1.     nucleolus

2.     prophage

3.     endospore

4.     nucleoid

A) 4 only

B) 1 and 3

C) 2 and 3

D) 3 and 4

E) 2, 3, and 4

 

D) 3 and 4

399

58) The cell also lacks F factors and F plasmids. Upon its death, this bacterium should be able to participate in

A) conjugation.

B) transduction.

C) transformation.

D) Three of the responses above are correct.

E) Two of the responses above are correct.

 

C) transformation.

400

59) This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Thus, this bacterium should be an

A) aerobic chemoheterotroph.

B) aerobic chemoautotroph.

C) anaerobic chemoheterotroph.

D) anaerobic chemoautotroph.

 

C) anaerobic chemoheterotroph.

401

60) This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Humans lacking this bacterium have no measurable reproductive advantage or disadvantage relative to humans who harbor this bacterium. Consequently, the bacterium can be properly described as which of the following?

1.     symbiont

2.     endosymbiont

3.     mutualist

4.     commensal

A) 4 only

B) 1 and 2

C) 1 and 4

D) 2 and 3

E) 2 and 4

 

C) 1 and 4

402

 

61) Given that the enzymes that catalyze nitrogen fixation are inhibited by oxygen, what are two "strategies" that nitrogen-fixing prokaryotes might use to protect these enzymes from oxygen?

1.     couple them with photosystem II (the photosystem that splits water molecules)

2.     package them in membranes that are impermeable to all gases

3.     be obligate anaerobes

4.     be strict aerobes

5.     package these enzymes in specialized cells or compartments that inhibit oxygen entry

A) 1 and 4

B) 2 and 4

C) 2 and 5

D) 3 and 4

E) 3 and 5

 

E) 3 and 5

403

62) Which two questions below arise from a careful reading of this quotation, and are most important for understanding how N2 enters heterocysts, and how O2 is kept out of heterocysts?

1.     If carbohydrates can enter the heterocysts from neighboring cells via the "intracellular  connections," how is it that O2 doesn't also enter via this route?

2.     If the cell walls of Anabaena's photosynthetic cells are permeable to O2 and CO2, are they also permeable to N2?

3.     If the nuclei of the photosynthetic cells contain the genes that code for nitrogen fixation, how can these cells fail to perform nitrogen fixation?

4.     If the nuclei of the heterocysts contain the genes that code for photosynthesis, how can these cells fail to perform photosynthesis?

5.     If the cell walls of Anabaena's heterocysts are permeable to N2, how is it that N2 doesn't diffuse out of the heterocysts before it can be fixed?

6.     If the thick cell walls of the heterocysts exclude entry of oxygen gas, how is it that they don't also exclude the entry of nitrogen gas?

A) 1 and 3

B) 1 and 6

C) 2 and 5

D) 3 and 4

E) 4 and 6

 

B) 1 and 6

404

63) Which two species should have much more phospholipid, in the form of bilayers, in their cytoplasms than most other bacteria?

A) species A and B

B) species A and C

C) species B and E

D) species C and D

E) species C and E

 

C) species B and E

405

64) Which species should be able to respond most readily to taxes (plural of taxis)?

A) species A

B) species B

C) species C

D) species D

E) species E

 

C) species C

406

65) How many of these species probably have a cell wall that partly consists of an outer membrane of lipopolysaccharide?

A) only one species

B) two species

C) three species

D) four species

E) all five species

 

C) three species

407

66) Gram-variable prokaryotes are, sometimes, those without any peptidoglycan. Which two species are most likely to be archaeans?

A) species A and B

B) species A and C

C) species B and E

D) species C and D

E) species C and E

 

A) species A and B

408

67) Species D is pathogenic if it gains access to the human intestine. Which other species, if it coinhabited a human intestine along with species D, is most likely to result in a recombinant species that is both pathogenic and resistant to some antibiotics?

A) species A

B) species B

C) species C

D) species D

E) species E

 

C) species C

409

68) Which species might be able to include Hfr cells?

A) species A

B) species B

C) species C

D) species D

E) species E

 

D) species D

410

69) Which species is most self-sustaining in terms of obtaining nutrition in environments containing little fixed nitrogen or carbon?

A) species A

B) species B

C) species C

D) species D

E) species E

 

E) species E

411

70) Which two species might be expected to cooperate metabolically, perhaps forming a biofilm wherein one species surrounds cells of the other species?

A) species A and B

B) species A and C

C) species B and E

D) species C and D

E) species C and E

 

A) species A and B

412

71) Which species is most likely to be found both in sewage treatment plants and in the guts of cattle?

A) species A

B) species B

C) species C

D) species D

E) species E

 

B) species B

413

72) Which species is probably an important contributor to the base of aquatic food chains as a primary producer?

A) species A

B) species B

C) species C

D) species D

E) species E

 

E) species E

414

73) Genetic variation in bacterial populations cannot result from

A) transduction.

B) transformation

C) conjugation

D) mutation.

E) meiosis.

 

E) meiosis.

415

 

74) Photoautotrophs use

A) light as an energy source and CO2 as a carbon source.

B) light as an energy source and methane as a carbon source.

C) N2 as an energy source and CO2 as a carbon source.

D) CO2 as both an energy source and a carbon source.

E) H2S as an energy source and CO2 as a carbon source.

 

A) light as an energy source and CO2 as a carbon source.

416

 

75) Which of the following statements is not true?

A) Archaea and bacteria have different membrane lipids.

B) Both archaea and bacteria generally lack membrane-enclosed organelles.

C) The cell walls of archaea lack peptidoglycan.

D) Only bacteria have histones associated with DNA.

E) Only some archaea use CO2 to oxidize H2, releasing methane.

 

D) Only bacteria have histones associated with DNA.

417

76) Which of the following involves metabolic cooperation among prokaryotic cells?

A) binary fission

B) endospore formation

C) endotoxin release

D) biofilms

E) photoautotrophy

 

D) biofilms

418

 

77) Bacteria perform each of the following ecological roles. Which role typically does not involve a symbiosis?

A) skin commensalist

B) decomposer

C) aggregates with methane-consuming archaea

D) gut mutualist

E) pathogen

 

B) decomposer

419

78) Plantlike photosynthesis that releases O2 occurs in

A) cyanobacteria.

B) chlamydias.

C) archaea.

D) actinomycetes.

E) chemoautotrophic bacteria.

 

A) cyanobacteria.