Q: A population of 320 red flowers ($C^R C^R$), 160 pink flowers ($C^R C^W$), and 20 white flowers ($C^W C^W$) is observed. What is the frequency of the $C^W$ allele?

$q = \frac{(20 \times 2) + 160}{(320 + 160 + 20) \times 2} = \frac{40 + 160}{1000} = 0.2$

Question 1

Which of the following best describes microevolution?

Accepted Answer

A change in allele frequencies in a population over generations.

Question 2

In a population of wildflowers, the frequency of allele $C^R$ is 0.8 and the frequency of allele $C^W$ is 0.2. According to Hardy-Weinberg equilibrium, what is the expected frequency of heterozygotes ($C^R C^W$)?

Accepted Answer

$2pq = 2(0.8)(0.2) = 0.32$

Question 3

Which of the following mechanisms is the ultimate source of genetic variation in populations?

Accepted Answer

Mutation

Question 4

A population of finches on Daphne Major Island experienced a drought that reduced seed availability. Which evolutionary process led to an increase in average beak depth in the population?

Accepted Answer

Natural selection

Question 5

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

Accepted Answer

Small population size

Question 6

A small group of individuals colonizes a new island, resulting in a population with allele frequencies different from the original population. This scenario is an example of:

Accepted Answer

Founder effect

Question 7

Which statement best explains why natural selection cannot produce 'perfect' organisms?

Accepted Answer

Evolution is limited by historical constraints, genetic variation, and trade-offs.

Question 8

In a population of 500 diploid individuals, how many total alleles are present at a gene locus?

Accepted Answer

1000

Question 9

Which of the following is a consequence of genetic drift in small populations?

Accepted Answer

Harmful alleles can become fixed by chance.

Question 10

A population of mosquitoes near the coast has a high frequency of an allele conferring resistance to insecticide. Over time, the frequency of this allele decreases with increasing distance from the coast. Which evolutionary mechanism is most likely responsible for this pattern?

Accepted Answer

Gene flow

Question 11

Which type of selection maintains two or more phenotypic forms in a population, such as the sickle-cell allele in regions with malaria?

Accepted Answer

Balancing selection

Question 12

If $p$ and $q$ represent the frequencies of two alleles at a locus, which equation correctly represents the sum of their frequencies?

Accepted Answer

$p + q = 1$

Question 13

Which of the following best describes frequency-dependent selection?

Accepted Answer

Selection in which the fitness of a phenotype depends on its frequency in the population.

Question 14

Sexual selection differs from natural selection in that sexual selection:

Accepted Answer

Acts on traits that improve mating success, which may not always improve survival.

Question 15

Which of the following scenarios illustrates the bottleneck effect?

Accepted Answer

A population is reduced to a few individuals due to a natural disaster, resulting in reduced genetic diversity.

Question 16

Which of the following is NOT a direct result of gene flow between populations?

Accepted Answer

Decreased genetic variation within a population.

Question 17

A population of 320 red flowers ($C^R C^R$), 160 pink flowers ($C^R C^W$), and 20 white flowers ($C^W C^W$) is observed. What is the frequency of the $C^W$ allele?

Accepted Answer

$q = \frac{(20 	imes 2) + 160}{(320 + 160 + 20) 	imes 2} = \frac{40 + 160}{1000} = 0.2$

Question 18

Which of the following is a limitation of natural selection?

Accepted Answer

Natural selection can only act on existing variation.

Question 19

Which of the following best explains why genetic drift is more significant in small populations?

Accepted Answer

Random changes in allele frequencies have a larger impact when there are fewer individuals.

Question 20

Which equation represents the expected genotype frequencies under Hardy-Weinberg equilibrium for a gene with two alleles, $p$ and $q$?

Accepted Answer

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

Chapter 21: The Evolution of Populations – Study Notes

Study Guide - Practice Questions

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