Question 1

When genes at many loci affect a character,

Accepted Answer

A)   the trait is more likely to occur in a smooth distribution.
B)   natural selection cannot act on the character.
C)   the environment is less likely to affect the character.
D)   both a and c are correct.

Question 2

Which of the following decreases genetic variation?

Accepted Answer

A)   Mutation
B)   Selection
C)   Recombination
D)   Gene flow

Question 3

Characters are more likely to exhibit continuous variation when

Accepted Answer

A)   there are no environmental effects.
B)   they are affected by alleles at more than one locus.
C)   inheritance is blending rather than particulate.
D)   there are only two alleles.

Question 4

Consider a population of 20 AA, 40 Aa, and 40 aa individuals. A is a dominant allele causing death before reproductive age. What are the genotypic frequencies of the next generation after selection?

Accepted Answer

A)   All AA individuals
B)   All aa individuals
C)   50% AA and 50% aa individuals
D)   25% AA and 75% aa individuals B

Question 5

Mutation can maintain variation because

Accepted Answer

A)   every mutation results in adaptation.
B)   directional selection is constantly working.
C)   a considerable amount of variation is protected from selection.
D)   the rates of mutation are very high.

Question 6

For male soapberry bugs, behavioral plasticity is costly because

Accepted Answer

A)   males must cooperate with other males to guard females.
B)   flexibility requires longer appendages.
C)   males will sometimes make mistakes about the local sex ratio and behave inappropriately.
D)   flexible males have to grow larger and therefore need more food.

Question 7

Local adaptations are called ________ constraints.

Accepted Answer

A)   optimal
B)   fixed
C)   developmental
D)   genetic

Question 8

Natural selection can move a population beyond its initial range of variation because

Accepted Answer

A)   there is hidden variation.
B)   alleles for extreme phenotypes are not concentrated in any one individual.
C)   there is no hidden variation.
D)   both a and

Question 9

Humans have a nearly insatiable appetite for sugar, fat, and salt because

Accepted Answer

A)   we are in perfect equilibrium with regard to such appetites.
B)   these appetites are always adaptive.
C)   such appetites were adaptive in ancient environments.
D)   these appetites are adaptive in our modern environment.

Question 10

Explain how natural selection can shape flexible behavioral responses.

Accepted Answer

The key concept students need to underst...

Question 11

The fact that all modern breeds of dog stem from wild wolves is evidence that

Accepted Answer

A)   selection can move a population beyond its initial range of variation.
B)   there is plenty of hidden variation.
C)   selection is weak.
D)   Both a and b are correct.

Question 12

Which of the following statements is correct?

Accepted Answer

A)   Hidden variation is not always present in continuously evolving traits.
B)   Selection causes genotypic frequencies to reach equilibrium in one generation, and the distribution of phenotypes does not change.
C)   Selection can lead to cumulative, long-term change.
D)   Genetic variation is always expressed as phenotypic variation.

Question 13

Evolutionary change in a phenotype

Accepted Answer

A)   results from change in the environment only.
B)   reflects change in the underlying genetic composition of a population.
C)   cannot be passed from parent to offspring.
D)   Both a and

Question 14

How can small population size affect gene frequencies? When is fixation reached?

Accepted Answer

Small population sizes affect gene frequ...

Question 15

Consider a population of 20 aa, 32 Aa, and 48 AA individuals. Selection acts against the lethal recessive homozygote (aa)  before adulthood. After selection, survivors mate randomly. What are the genotypic frequencies of the next generation?

Accepted Answer

A)   25% aa, 50% Aa, and 25% AA
B)   All AA
C)   4% aa, 16% Aa, and 64% AA
D)   None of the above.

Question 16

Correlated characters

Accepted Answer

A)   can occur because some genes affect more than one character.
B)   change independently.
C)   are always positively related.
D)   make natural selection longer. A

Question 17

For most continuously varying characters, offspring are intermediate between their parents because

Accepted Answer

A)   of blending inheritance.
B)   genetic transmission involves faithful copying of the genes themselves and their reassembly into different combinations in zygotes.
C)   mutation is constantly introducing new alleles, some of which will produce new phenotypes.
D)   natural selection reduces variation.

Question 18

Low rates of mutation can maintain variation in a population because many different genotypes generate intermediate phenotypes that are favored by ________ selection.

Accepted Answer

A)   stabilizing
B)   disruptive
C)   directional
D)   All of the above.

Question 19

The compound eye cannot evolve into the camera-type eye because

Accepted Answer

A)   natural selection does not change adaptations.
B)   the compound eye is always superior to the camera-type eye.
C)   the compound eye is a local optimum.
D)   the camera-type eye is a local optimum.

Question 20

Male soapberry bugs adjust their mate-guarding behavior

Accepted Answer

A)   in places where the environment is stable.
B)   in places where the environment is variable.
C)   in colder climates.
D)   in wetter climates. B

Exam 3: The Modern Synthesis

When genes at many loci affect a character,

Correct AnswerverifiedShow Answer

Which of the following decreases genetic variation?

Correct AnswerverifiedShow Answer

Characters are more likely to exhibit continuous variation when

Correct AnswerverifiedShow Answer

Consider a population of 20 AA, 40 Aa, and 40 aa individuals. A is a dominant allele causing death before reproductive age. What are the genotypic frequencies of the next generation after selection?

Correct AnswerverifiedB

Mutation can maintain variation because

Correct AnswerverifiedShow Answer

For male soapberry bugs, behavioral plasticity is costly because

Correct AnswerverifiedShow Answer

Local adaptations are called ________ constraints.

Correct AnswerverifiedShow Answer

Natural selection can move a population beyond its initial range of variation because

Correct AnswerverifiedShow Answer

Humans have a nearly insatiable appetite for sugar, fat, and salt because

Correct AnswerverifiedShow Answer

Explain how natural selection can shape flexible behavioral responses.

Correct AnswerverifiedThe key concept students need to underst...View AnswerShow Answer

The fact that all modern breeds of dog stem from wild wolves is evidence that

Correct AnswerverifiedShow Answer

Which of the following statements is correct?

Correct AnswerverifiedShow Answer

Evolutionary change in a phenotype

Correct AnswerverifiedShow Answer

How can small population size affect gene frequencies? When is fixation reached?

Correct AnswerverifiedSmall population sizes affect gene frequ...View AnswerShow Answer

Consider a population of 20 aa, 32 Aa, and 48 AA individuals. Selection acts against the lethal recessive homozygote (aa) before adulthood. After selection, survivors mate randomly. What are the genotypic frequencies of the next generation?

Correct AnswerverifiedShow Answer

Correlated characters

Correct AnswerverifiedA

For most continuously varying characters, offspring are intermediate between their parents because

Correct AnswerverifiedShow Answer

Low rates of mutation can maintain variation in a population because many different genotypes generate intermediate phenotypes that are favored by ________ selection.

Correct AnswerverifiedShow Answer

The compound eye cannot evolve into the camera-type eye because

Correct AnswerverifiedShow Answer

Male soapberry bugs adjust their mate-guarding behavior

Correct AnswerverifiedB

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B

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The key concept students need to underst...
View Answer

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Small population sizes affect gene frequ...
View Answer

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A

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B