Question 1

Which of the following statements describe the effect of evolution on a population?

Accepted Answer

A)  increasingly better match between a population and its environment 
B)  increased genetic variation among individuals in a population 
C)  increased variation among individuals in a population 
D)  increased sexual reproduction in a population

Question 2

For which one of the following observations were both Lamarck's hypothesis and Darwin's hypothesis in complete agreement?

Accepted Answer

A)  Use and disuse of organs determines their size in progeny. 
B)  Gradual evolutionary change explains why organisms are well-suited to their environments. 
C)  Acquired characteristics are inherited. 
D)  More complex species are descended from less complex species.

Question 3

Given what we know about evolutionary biology, we expect to find the largest number of endemic species in which of the following geological features, which have existed for at least a few million years?

Accepted Answer

A)  an isolated ocean island in the tropics 
B)  an extensive mountain range 
C)  a grassland in the center of a large continent, with extreme climatic conditions 
D)  a shallow estuary on a warm-water coast

Question 4

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

Accepted Answer

A)  Some of the organisms depicted by the tree lived in different habitats. 
B)  The skeletal remains of the organisms depicted by the tree were incomplete (in other words, some bones were missing). 
C)  Transitional fossils had not been found. 
D)  Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

Question 5

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?

Accepted Answer

A)  Forelimb evolution was adaptive in people and bats, but not in whales. 
B)  Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy. 
C)  Genes mutate faster in whales than in humans or bats. 
D)  Whales are not properly classified as mammals.

Question 6

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

Accepted Answer

A)  theories 
B)  hypotheses 
C)  dogmas 
D)  facts

Question 7

In a hypothetical environment, fishes called pike-cichlids are visual predators of large, adult algae-eating fish (in other words, they locate their prey by sight). The population of algae-eaters experiences predatory pressure from pike-cichlids. Which of the following is least likely to result in the algae-eater population in future generations?

Accepted Answer

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

Question 8

The greatest number of endemic species is expected in environments that are ________.

Accepted Answer

A)  easily reached and ecologically diverse 
B)  isolated and show little ecological diversity 
C)  isolated and ecologically diverse 
D)  easily reached and show little ecological diversity

Question 9

The following question is based on information from Frank M. Frey, "Opposing Natural Selection from Herbivores and Pathogens May Maintain Floral-Color Variation in Claytonia virginica (Portulacaceae)," Evolution 58(11), 2004: 2426-37.
Claytonia virginica is a woodland spring herb with flowers that vary from white, to pale pink, to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so that Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time?

Accepted Answer

A)  The percentage of pink flowers should increase over time. 
B)  The percentage of white flowers should increase over time. 
C)  The distribution of flower colors should not change. 
D)  The distribution of flower colors should randomly fluctuate over time.

Question 10

The following questions refer to the figure below, which shows an outcrop of sedimentary rock whose strata are labeled A-D.

If x indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D

Question 11

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should ________.

Accepted Answer

A)  test whether other traits in these males are also adaptive 
B)  look for evidence of hair in ancestors of tamarins 
C)  determine if hair length is heritable 
D)  test whether males with shaved heads are still able to mate

Question 12

Starting from the wild mustard Brassica oleracea, breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Therefore, which of the following statements is correct?

Accepted Answer

A)  In this wild mustard, there is enough heritable variation to permit these different varieties. 
B)  Heritable variation is low in wild mustard-otherwise this wild strain would have different characteristics. 
C)  Natural selection is rare in wild populations of wild mustard. 
D)  In wild mustard, most of the variation is due to differences in soil or other aspects of the environment.

Question 13

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

Accepted Answer

A)  convergent evolution 
B)  a homologous structure 
C)  natural selection 
D)  a vestigial trait

Question 14

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

Accepted Answer

A)  All habitats should have received applications of DDT at about the same time. 
B)  The frequency of DDT application should have been higher. 
C)  None of the insect pests would have genetic variations that resulted in DDT resistance. 
D)  DDT application should have been continual.

Question 15

Which one of the following statements best defines artificial selection?

Accepted Answer

A)  Process that occurs when individuals inherit traits that enable them to survive and reproduce 
B)  Process where humans decide which plants and/or animals will not breed 
C)  Process of human directed breeding aimed to produce selective traits in selected species 
D)  Process that favors beneficial mutations

Question 16

The cow Bos primigenius (which is bred for meat and milk)has a smaller brain and larger eyes than closely related wild species of ungulates. These traits most likely arose by ________.

Accepted Answer

A)  natural selection, because these traits evolved in the population over time 
B)  natural selection, because these traits were not consciously selected by humans 
C)  artificial selection, because changes in these traits co-occurred with human selection for high milk output and high muscle content 
D)  artificial selection, because these animals differ from their close relatives and common ancestor

Question 17

Fossils found in strata reveal that ________.

Accepted Answer

A)  older strata carry fossils that differ greatly from living organisms 
B)  geologic changes occur quickly on Earth 
C)  unused body parts decrease in size 
D)  innate drive to complexity of life

Question 18

What must be true of any organ described as vestigial?

Accepted Answer

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.

Question 19

The Linnaeus classification system grouped organisms by ________.

Accepted Answer

A)  linear hierarchy of the scala naturae 
B)  increasingly more general categories 
C)  increasingly more complex categories 
D)  environmental location

Question 20

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these statements explains why the pigweed reappeared?

Accepted Answer

A)  The herbicide company lost its triazine formula and started selling poor-quality triazine. 
B)  Natural selection caused the pigweed to mutate, creating a new triazine-resistant species. 
C)  Triazine-resistant pigweed has less-efficient photosynthesis metabolism. 
D)  Triazine-resistant weeds were more likely to survive and reproduce.

Exam 22: Descent with Modification: A Darwinian View of Life