Question 1

Which of the following best describes microevolution?

Accepted Answer

Evolution that occurs within populations, resulting in changes in allele frequencies over generations.

Question 2

A population of 500 animals has the following genotypes: 320 WW, 160 Ww, and 20 ww. What is the frequency of the w allele in the gene pool?

Accepted Answer

0.2

Question 3

Which equation is used to determine if a population is in Hardy-Weinberg equilibrium?

Accepted Answer

$$p^2 + 2pq$$ + $$q^2 = 1$

Question 4

Which of the following is NOT a condition required for Hardy-Weinberg equilibrium?

Accepted Answer

Small population size

Question 5

If a population is in Hardy-Weinberg equilibrium, what will happen to allele frequencies over successive generations?

Accepted Answer

They will remain constant.

Question 6

Which mechanism of microevolution is most likely to cause a drastic reduction in genetic variation due to a sudden decrease in population size?

Accepted Answer

Bottleneck effect

Question 7

In the founder effect, why is the frequency of certain alleles often higher in the new population than in the original population?

Accepted Answer

Because the founders carry a random subset of alleles from the original population.

Question 8

Which of the following consistently leads to adaptive evolution?

Accepted Answer

Natural selection

Question 9

A population of snails is exposed to predation by crabs. Over several generations, the average shell thickness increases. Which type of natural selection is most likely occurring?

Accepted Answer

Directional selection

Question 10

Which of the following is an example of gene flow?

Accepted Answer

A population of birds migrates to a new area and breeds with the local population, introducing new alleles.

Question 11

In a population, the frequency of allele W is $$p = 0.8$$ and the frequency of allele w is $$q = 0.2. $$What is the expected frequency of heterozygotes (Ww) under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 0.32$$

Question 12

Which scenario best illustrates stabilizing selection?

Accepted Answer

Human birth weight remains around an average value, with very high and very low weights selected against.

Question 13

Which of the following is a plausible consequence of the bottleneck effect in a population?

Accepted Answer

Loss of rare alleles

Question 14

Which mechanism of microevolution is most likely responsible for the high frequency of retinitis pigmentosa on Tristan da Cunha?

Accepted Answer

Founder effect

Question 15

Sexual selection is best defined as:

Accepted Answer

A form of natural selection in which individuals with certain traits are more likely to obtain mates.

Question 16

Which of the following would violate the Hardy-Weinberg equilibrium in a population?

Accepted Answer

Natural selection favoring a particular genotype

Question 17

A population of prairie chickens experienced a drastic reduction in numbers due to habitat loss. What was the effect on genetic diversity, and how was it addressed?

Accepted Answer

Genetic diversity decreased; researchers introduced birds from neighboring states to increase diversity.

Question 18

Which formula represents the sum of allele frequencies in a population?

Accepted Answer

$$p + q = 1$$

Question 19

In the Darwinian Snails simulation, what happened to the population when crabs preferentially ate snails with thin shells?

Accepted Answer

The population evolved to have more thick-shelled snails.

Question 20

Which of the following best explains why most populations are not in Hardy-Weinberg equilibrium?

Accepted Answer

All five conditions required for equilibrium are rarely met in nature.

Microevolution: How Populations Evolve

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