Question 1

Which statement about allele frequencies is not true?

Accepted Answer

A)  The sum of all allele frequencies at a locus is always 1. 
B)  If there are two alleles at a locus and we know the frequency of one of them, we can obtain the frequency of the other by subtraction. 
C)  If an allele is missing from a population, its frequency in that population is 0. 
D)  If two populations have the same allele frequencies at a locus, they must have the same proportion of homozygotes at that locus. 
E)  If there is only one allele at a locus, its frequency is 1. 
A)  The sum of all allele frequencies at a locus is always 1. 
B)  If there are two alleles at a locus and we know the frequency of one of them, we can obtain the frequency of the other by subtraction. 
C)  If an allele is missing from a population, its frequency in that population is 0. 
D)  If two populations have the same allele frequencies at a locus, they must have the same proportion of homozygotes at that locus. 
E)  If there is only one allele at a locus, its frequency is 1.

Question 2

Genetic variation is

Accepted Answer

A)  favored by variation in the environment. 
B)  maintained in subpopulations of the same species. 
C)  generated by recombination. 
D)  disfavored by frequency-dependent selection. 
E)  a, b, and c 
A)  favored by variation in the environment. 
B)  maintained in subpopulations of the same species. 
C)  generated by recombination. 
D)  disfavored by frequency-dependent selection. 
E)  a, b, and c

Question 3

Use the following to answer questions:
Suppose you have a population of flour beetles with 1,000 individuals. Normally the beetles are red; however, this population is polymorphic for a mutant autosomal body color, black, designated by b/b. Red is dominant to black, so B/B and B/b genotypes are red. Assume the population is in Hardy-Weinberg equilibrium, with equal frequencies of the two alleles.
-What would be the expected red and black allele frequencies if 1000 black individuals migrated into the population?

Accepted Answer

A)  0.75 red; 0.25 black 
B)  0.25 red; 0.75 black 
C)  0.33 red; 0.67 black 
D)  They would not change because the population would still be in Hardy-Weinberg equilibrium. 
E)  None of the above 
A)  0.75 red; 0.25 black 
B)  0.25 red; 0.75 black 
C)  0.33 red; 0.67 black 
D)  They would not change because the population would still be in Hardy-Weinberg equilibrium. 
E)  None of the above

Question 4

Suppose the population size of a species of field mice is two million. It has a mutation rate of 2 $\times$ 10-9 and its genome size is three billion. The number of new mutations that appear in this species would be about _______.

Accepted Answer

The answer of Suppose the population size of a species...

Question 5

Which of the following tends to reduce genetic variation within populations?

Accepted Answer

A)  Genetic drift 
B)  Stabilizing selection 
C)  Directional selection 
D)  All of the above 
E)  None of the above 
A)  Genetic drift 
B)  Stabilizing selection 
C)  Directional selection 
D)  All of the above 
E)  None of the above

Question 6

Which of the following would not be considered an example of a trade-off?

Accepted Answer

A)  Brightly colored male guppies are more successful at acquiring mates than other males but are more likely to be killed by predators. 
B)  Humans that carry the e4 allele for the Apo-E gene are at greater risk than individuals without this allele for acquiring Alzheimer's and coronary heart disease. 
C)  Rats that are resistant to the poison warfarin have an increased need for vitamin K. 
D)  All of the above 
E)  None of the above 
A)  Brightly colored male guppies are more successful at acquiring mates than other males but are more likely to be killed by predators. 
B)  Humans that carry the e4 allele for the Apo-E gene are at greater risk than individuals without this allele for acquiring Alzheimer's and coronary heart disease. 
C)  Rats that are resistant to the poison warfarin have an increased need for vitamin K. 
D)  All of the above 
E)  None of the above

Question 7

Evolution occurs at the level of

Accepted Answer

A)  the individual genotype. 
B)  the individual phenotype. 
C)  environmentally based phenotypic variation. 
D)  the population. 
E)  the species 
A)  the individual genotype. 
B)  the individual phenotype. 
C)  environmentally based phenotypic variation. 
D)  the population. 
E)  the species

Question 8

Which of the following modes of selection results in a decrease in variation?

Accepted Answer

A)  Stabilizing selection only 
B)  Directional selection only 
C)  Disruptive selection only 
D)  Both directional and disruptive selection 
E)  Both stabilizing and directional selection 
A)  Stabilizing selection only 
B)  Directional selection only 
C)  Disruptive selection only 
D)  Both directional and disruptive selection 
E)  Both stabilizing and directional selection

Question 9

Darwin published The Origin of Species

Accepted Answer

A)  before 1840. 
B)  between 1841 and 1880. 
C)  between 1881 and 1920. 
D)  between 1921 and 1960. 
E)  after 1960. 
A)  before 1840. 
B)  between 1841 and 1880. 
C)  between 1881 and 1920. 
D)  between 1921 and 1960. 
E)  after 1960.

Question 10

Genetic variation within a population may be maintained by

Accepted Answer

A)  frequency-dependent selection. 
B)  the accumulation of neutral alleles. 
C)  sexual recombination. 
D)  heterozygote advantage. 
E)  All of the above 
A)  frequency-dependent selection. 
B)  the accumulation of neutral alleles. 
C)  sexual recombination. 
D)  heterozygote advantage. 
E)  All of the above

Question 11

According to the scientific definition of the word theory, a theory is

Accepted Answer

A)  a hypothesis. 
B)  largely a matter of guesswork. 
C)  a large body of knowledge. 
D)  an estimate. 
E)  a supposition. 
A)  a hypothesis. 
B)  largely a matter of guesswork. 
C)  a large body of knowledge. 
D)  an estimate. 
E)  a supposition.

Question 12

When researchers observe populations that have large deviations from Hardy-Weinberg equilibrium, they can safely dismiss which of the following mechanisms as the explanation for the deviation?

Accepted Answer

A)  Natural selection 
B)  Gene flow 
C)  Nonrandom mating 
D)  Mutation 
E)  None of the above 
A)  Natural selection 
B)  Gene flow 
C)  Nonrandom mating 
D)  Mutation 
E)  None of the above

Question 13

Suppose that females of a species of beetles prefer to mate with males that have relatively rare color patterns. This observation would be an illustration of

Accepted Answer

A)  Muller's ratchet. 
B)  genetic drift. 
C)  the founder effect. 
D)  frequency-dependent selection. 
E)  disruptive selection. 
A)  Muller's ratchet. 
B)  genetic drift. 
C)  the founder effect. 
D)  frequency-dependent selection. 
E)  disruptive selection.

Question 14

Studies of enzyme genotypes and flight in Colias butterflies showed that

Accepted Answer

A)  males that are heterozygous at PGI are always inferior in flight compared to homozygotes. 
B)  males that are heterozygous at PGI have greater mating success than homozygous males because they are able to fly farther in a broad range of temperatures. 
C)  genotypes at PGI do not affect flight ability. 
D)  flight ability and mating success are not correlated. 
E)  flight ability can be explained by Muller's ratchet. 
A)  males that are heterozygous at PGI are always inferior in flight compared to homozygotes. 
B)  males that are heterozygous at PGI have greater mating success than homozygous males because they are able to fly farther in a broad range of temperatures. 
C)  genotypes at PGI do not affect flight ability. 
D)  flight ability and mating success are not correlated. 
E)  flight ability can be explained by Muller's ratchet.

Question 15

Disruptive selection maintains a bimodal distribution of bill size in the West African seedcracker because

Accepted Answer

A)  bills of intermediate shapes are difficult to form. 
B)  the birds' two major food sources differ markedly in size and hardness. 
C)  males use their large bills in displays. 
D)  migrants introduce different bill sizes into the population each year. 
E)  older birds need larger bills than younger birds. 
A)  bills of intermediate shapes are difficult to form. 
B)  the birds' two major food sources differ markedly in size and hardness. 
C)  males use their large bills in displays. 
D)  migrants introduce different bill sizes into the population each year. 
E)  older birds need larger bills than younger birds.

Question 16

Describe what is meant by sexual selection and how the sexual selection of tail length in male widowbirds was studied by behavioral ecologists as described in the textbook.

Accepted Answer

Sexual selection is the spread of a trai

Question 17

What was Darwin's explanation for the evolution of bright colors and other apparently useless (and potentially deleterious) but conspicuous characters in males of many species?

Accepted Answer

A)  Stabilizing selection 
B)  Genetic drift 
C)  Sexual selection 
D)  Disruptive selection 
E)  Gene flow 
A)  Stabilizing selection 
B)  Genetic drift 
C)  Sexual selection 
D)  Disruptive selection 
E)  Gene flow

Question 18

The Hardy-Weinberg expression is an expansion of a binomial, or (p + q)2 = p2 + 2pq + q2. In this equation, the left-hand side represents _______ frequencies, and the right-hand side represents _______ frequencies.

Accepted Answer

Question 19

Which of the following statements about sexual selection is true?

Accepted Answer

A)  Traits favored by sexual selection are often costly to males. 
B)  Sexual selection operates primarily on survival success. 
C)  Females gain a fitness benefit by choosing males on the basis of traits that can easily be faked. 
D)  Darwin's contemporaries immediately recognized the importance of his ideas about sexual selection. 
E)  Sexual selection applies to the ability of individuals of one sex to compete for access to members of the opposite sex, not to matters of sexual attractiveness. 
A)  Traits favored by sexual selection are often costly to males. 
B)  Sexual selection operates primarily on survival success. 
C)  Females gain a fitness benefit by choosing males on the basis of traits that can easily be faked. 
D)  Darwin's contemporaries immediately recognized the importance of his ideas about sexual selection. 
E)  Sexual selection applies to the ability of individuals of one sex to compete for access to members of the opposite sex, not to matters of sexual attractiveness.

Question 20

Which of the following is not a goal of population genetics?

Accepted Answer

A)  Explaining the patterns of genetic variation 
B)  Explaining how genotypic information is expressed as phenotypic traits 
C)  Explaining the origins of genotypic variation 
D)  Understanding the mechanisms by which allele frequencies change in populations 
E)  Explaining how genetic variation is maintained 
A)  Explaining the patterns of genetic variation 
B)  Explaining how genotypic information is expressed as phenotypic traits 
C)  Explaining the origins of genotypic variation 
D)  Understanding the mechanisms by which allele frequencies change in populations 
E)  Explaining how genetic variation is maintained

Exam 21: Evidence and Mechanisms of Evolution

Which statement about allele frequencies is not true?

Genetic variation is

Suppose the population size of a species of field mice is two million. It has a mutation rate of 2 ×\times× 10-9 and its genome size is three billion. The number of new mutations that appear in this species would be about _______.

Which of the following tends to reduce genetic variation within populations?

Which of the following would not be considered an example of a trade-off?

Evolution occurs at the level of

Which of the following modes of selection results in a decrease in variation?

Darwin published The Origin of Species

Genetic variation within a population may be maintained by

According to the scientific definition of the word theory, a theory is

When researchers observe populations that have large deviations from Hardy-Weinberg equilibrium, they can safely dismiss which of the following mechanisms as the explanation for the deviation?

Suppose that females of a species of beetles prefer to mate with males that have relatively rare color patterns. This observation would be an illustration of

Studies of enzyme genotypes and flight in Colias butterflies showed that

Disruptive selection maintains a bimodal distribution of bill size in the West African seedcracker because

Describe what is meant by sexual selection and how the sexual selection of tail length in male widowbirds was studied by behavioral ecologists as described in the textbook.

What was Darwin's explanation for the evolution of bright colors and other apparently useless (and potentially deleterious) but conspicuous characters in males of many species?

The Hardy-Weinberg expression is an expansion of a binomial, or (p + q)2 = p2 + 2pq + q2. In this equation, the left-hand side represents _______ frequencies, and the right-hand side represents _______ frequencies.

Which of the following statements about sexual selection is true?

Which of the following is not a goal of population genetics?

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Suppose the population size of a species of field mice is two million. It has a mutation rate of 2 $\times$ 10^-⁹ and its genome size is three billion. The number of new mutations that appear in this species would be about _______.

The Hardy-Weinberg expression is an expansion of a binomial, or (p + q)² = p² + 2pq + q². In this equation, the left-hand side represents _ frequencies, and the right-hand side represents _ frequencies.