Question 1

Habitat loss, natural catastrophes, and/or excessive harvesting of a species often result in:

Accepted Answer

A)  increased mutation rates.
B)  population bottlenecks.
C)  increased fitness of individuals.
D)  artificial selection.
E)  increased gene flow.

Question 2

Suppose a population of mostly sand-colored crabs migrates from a sand beach to a pebble beach and evolves a darker, speckled coloration that closely resembles the pebble beach. This is an example of:

Accepted Answer

A)  directional selection.
B)  stabilizing selection.
C)  disruptive selection.
D)  sexual selection.
E)  genetic drift.

Question 3

According to the Hardy-Weinberg principle, if 75% of the alleles in the gene pool are A1 and 25% are A2, what is the proportion of individuals with genotype A1A2 in this population?

Accepted Answer

A)  0) 1875
B)  0) 5625
C)  0) 375
D)  0) 0625
E)  0) 025

Question 4

A population that maintains several different phenotypes displays ________.

Accepted Answer

balanced p...

Question 5

Within a large population, if no mutations occur, no migration occurs, all matings are random, and each individual has an equal chance of reproducing, which of the following will probably happen?

Accepted Answer

A)  Extinction will result.
B)  A bottleneck will occur.
C)  Natural selection will occur at the normal rate for that species.
D)  A change in allele frequency will lead to rapid evolution.
E)  No evolution will occur.

Question 6

Mutations:

Accepted Answer

A)  can be helpful, neutral, or harmful to individuals.
B)  arise due to environmental pressures.
C)  are caused by natural selection.
D)  limit the potential for evolution.

Question 7

Suppose that the only population of a certain reptile species lives on an African mountain. If you could prevent all movement of individuals out of this large but isolated population, which of the following describes the most likely future of this reptile population?

Accepted Answer

A)  Evolution will promptly cease.
B)  The population will go extinct after a few generations because of inbreeding.
C)  Evolution will continue because of mutations, assortative mating, and genetic drift.
D)  The bottleneck effect will cause major evolutionary changes in the isolated population.
E)  The population will survive only as long as the environment remains constant.

Question 8

Antibiotic resistance is an example of ________ in bacteria.

Accepted Answer

The answer of Antibiotic resistance is an example of ________...

Question 9

Natural selection causes genetic changes in populations. True or False?

Accepted Answer

A) True 
 B)False

Question 10

In Central Africa, the frequency of the sickle-cell allele has remained stable over the years because the allele protects against malaria. In the United States, malaria was eradicated by eliminating the mosquito that spreads the disease. The decreasing frequency of the sickle-cell allele in African Americans since malaria was eliminated in the United States is an example of:

Accepted Answer

A)  directional selection.
B)  stabilizing selection.
C)  disruptive selection.
D)  genetic drift.
E)  the founder effect.

Question 11

Male fish that display a bright blue color attract more mates as well as more predators. Maintaining that blue gene in the population is an example of:

Accepted Answer

A)  the founder effect.
B)  a population bottleneck.
C)  coevolution.
D)  genetic drift.
E)  sexual selection.

Question 12

Imagine that a species of bird with an intermediate beak size becomes two separate species with large and small beaks. This is an example of:

Accepted Answer

A)  directional selection.
B)  stabilizing selection.
C)  disruptive selection.
D)  sexual selection.
E)  genetic drift.

Question 13

The elaborate courtship displays common among animals are the result of:

Accepted Answer

A)  random mating.
B)  sexual selection.
C)  spontaneous mutations.
D)  stabilizing selection.
E)  disruptive selection.

Question 14

Explain how a recessive trait can be the most frequent phenotype in a population.

Accepted Answer

Selection pressures can cause genetic drift via directional selection. This could favor the organisms showing the recessive trait while removing the dominant allele from the gene pool.

Question 15

Suppose a small population of deer is introduced to an island. All the original males have 6 to 10 points on their antlers, and the average male has 8 points. After several generations, if most males have antlers with 10 points and no males have 6 points, this is an example of ________ selection.

Accepted Answer

The answer of Suppose a small population of deer is...

Question 16

Explain how disruptive selection could lead to the development of two species from one original founding population.

Accepted Answer

Disruptive selection favors the extreme phenotypes of a population. Over time, this could lead to organisms so different that they are no longer able to reproduce with each other.

Question 17

Genetic drift results in a change in gene frequencies because:

Accepted Answer

A)  gene flow within the population is less than gene flow between populations.
B)  the population is so large that natural selection has little noticeable effect.
C)  the population size is so small that chance occurrences can alter gene frequencies.
D)  the population has not yet stabilized.

Question 18

Evolution by genetic drift is most obvious in:

Accepted Answer

A)  large populations.
B)  aquatic organisms.
C)  small populations.
D)  invertebrate species.
E)  migratory species. C

Question 19

Imagine that a mutation for red eye color becomes very common in a population of flies because female flies in this population prefer to mate with red-eyed males. This is an example of:

Accepted Answer

A)  directional selection.
B)  stabilizing selection.
C)  disruptive selection.
D)  sexual selection.
E)  genetic drift.

Question 20

Which of the following is an example of assortative mating?

Accepted Answer

A)  A dominant male elephant mates with most females in a group, excluding other males from mating with the females.
B)  A female mouse chooses a mate because he is the same color that she is.
C)  A female sparrow chooses a mate because he attracts her by singing the correct song.
D)  A female sheep chooses a mate because he has previously mated with many females.
E)  A female lizard chooses to mate with the first male she encounters.

Exam 15: How Populations Evolve

Habitat loss, natural catastrophes, and/or excessive harvesting of a species often result in:

Correct Answer
verified

Suppose a population of mostly sand-colored crabs migrates from a sand beach to a pebble beach and evolves a darker, speckled coloration that closely resembles the pebble beach. This is an example of:

Correct Answer
verified

According to the Hardy-Weinberg principle, if 75% of the alleles in the gene pool are A1 and 25% are A2, what is the proportion of individuals with genotype A1A2 in this population?

Correct Answer
verified

A population that maintains several different phenotypes displays ________.

Correct Answer
verified
balanced p...
View Answer

Within a large population, if no mutations occur, no migration occurs, all matings are random, and each individual has an equal chance of reproducing, which of the following will probably happen?

Correct Answer
verified

Mutations:

Correct Answer
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Suppose that the only population of a certain reptile species lives on an African mountain. If you could prevent all movement of individuals out of this large but isolated population, which of the following describes the most likely future of this reptile population?

Correct Answer
verified

Antibiotic resistance is an example of ________ in bacteria.

Correct Answer
verified

Natural selection causes genetic changes in populations. True or False?

Correct Answer
verified

Correct Answer
verified

Male fish that display a bright blue color attract more mates as well as more predators. Maintaining that blue gene in the population is an example of:

Correct Answer
verified

Imagine that a species of bird with an intermediate beak size becomes two separate species with large and small beaks. This is an example of:

Correct Answer
verified

The elaborate courtship displays common among animals are the result of:

Correct Answer
verified

Explain how a recessive trait can be the most frequent phenotype in a population.

Correct Answer
verified
Selection pressures can cause genetic drift via directional selection. This could favor the organisms showing the recessive trait while removing the dominant allele from the gene pool.

Suppose a small population of deer is introduced to an island. All the original males have 6 to 10 points on their antlers, and the average male has 8 points. After several generations, if most males have antlers with 10 points and no males have 6 points, this is an example of ________ selection.

Correct Answer
verified

Explain how disruptive selection could lead to the development of two species from one original founding population.

Correct Answer
verified
Disruptive selection favors the extreme phenotypes of a population. Over time, this could lead to organisms so different that they are no longer able to reproduce with each other.

Genetic drift results in a change in gene frequencies because:

Correct Answer
verified

Evolution by genetic drift is most obvious in:

Correct Answer
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C

Imagine that a mutation for red eye color becomes very common in a population of flies because female flies in this population prefer to mate with red-eyed males. This is an example of:

Correct Answer
verified

Which of the following is an example of assortative mating?

Correct Answer
verified

Exam 15: How Populations Evolve

Habitat loss, natural catastrophes, and/or excessive harvesting of a species often result in:

Correct AnswerverifiedShow Answer

Suppose a population of mostly sand-colored crabs migrates from a sand beach to a pebble beach and evolves a darker, speckled coloration that closely resembles the pebble beach. This is an example of:

Correct AnswerverifiedShow Answer

According to the Hardy-Weinberg principle, if 75% of the alleles in the gene pool are A1 and 25% are A2, what is the proportion of individuals with genotype A1A2 in this population?

Correct AnswerverifiedShow Answer

A population that maintains several different phenotypes displays ________.

Correct Answerverifiedbalanced p...View AnswerShow Answer

Within a large population, if no mutations occur, no migration occurs, all matings are random, and each individual has an equal chance of reproducing, which of the following will probably happen?

Correct AnswerverifiedShow Answer

Mutations:

Correct AnswerverifiedShow Answer

Suppose that the only population of a certain reptile species lives on an African mountain. If you could prevent all movement of individuals out of this large but isolated population, which of the following describes the most likely future of this reptile population?

Correct AnswerverifiedShow Answer

Antibiotic resistance is an example of ________ in bacteria.

Correct AnswerverifiedShow Answer

Natural selection causes genetic changes in populations. True or False?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Male fish that display a bright blue color attract more mates as well as more predators. Maintaining that blue gene in the population is an example of:

Correct AnswerverifiedShow Answer

Imagine that a species of bird with an intermediate beak size becomes two separate species with large and small beaks. This is an example of:

Correct AnswerverifiedShow Answer

The elaborate courtship displays common among animals are the result of:

Correct AnswerverifiedShow Answer

Explain how a recessive trait can be the most frequent phenotype in a population.

Correct AnswerverifiedSelection pressures can cause genetic drift via directional selection. This could favor the organisms showing the recessive trait while removing the dominant allele from the gene pool.

Suppose a small population of deer is introduced to an island. All the original males have 6 to 10 points on their antlers, and the average male has 8 points. After several generations, if most males have antlers with 10 points and no males have 6 points, this is an example of ________ selection.

Correct AnswerverifiedShow Answer

Explain how disruptive selection could lead to the development of two species from one original founding population.

Correct AnswerverifiedDisruptive selection favors the extreme phenotypes of a population. Over time, this could lead to organisms so different that they are no longer able to reproduce with each other.

Genetic drift results in a change in gene frequencies because:

Correct AnswerverifiedShow Answer

Evolution by genetic drift is most obvious in:

Correct AnswerverifiedC

Imagine that a mutation for red eye color becomes very common in a population of flies because female flies in this population prefer to mate with red-eyed males. This is an example of:

Correct AnswerverifiedShow Answer

Which of the following is an example of assortative mating?

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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balanced p...
View Answer

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Correct Answer
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Correct Answer
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Selection pressures can cause genetic drift via directional selection. This could favor the organisms showing the recessive trait while removing the dominant allele from the gene pool.

Correct Answer
verified

Correct Answer
verified
Disruptive selection favors the extreme phenotypes of a population. Over time, this could lead to organisms so different that they are no longer able to reproduce with each other.

Correct Answer
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Correct Answer
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C

Correct Answer
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Correct Answer
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