Question 1

Which of the following mechanisms is the only one that consistently leads to adaptive evolution in populations?

Accepted Answer

Natural selection

Question 2

A population of wildflowers consists of 320 red ($$C^R C^R$$), 160 pink ($$C^R C^W$$), and 20 white ($$C^W C^W) $$individuals. What is the frequency of the $$C^R$$ allele in this population?

Accepted Answer

$$0.80$$

Question 3

Which condition must be met for a population to remain in Hardy-Weinberg equilibrium?

Accepted Answer

No mutations

Question 4

In a population, the frequency of allele $$p is$$ $$0.7$$ and allele $$q is$$ $$0.3. $$According to the Hardy-Weinberg equation, what is the expected frequency of heterozygotes?

Accepted Answer

$$2pq = 0.42$$

Question 5

Which scenario best illustrates the bottleneck effect?

Accepted Answer

A population is drastically reduced by a hurricane, leaving only a few survivors

Question 6

What is the main consequence of genetic drift in small populations?

Accepted Answer

Random loss of alleles

Question 7

Which of the following is an example of gene flow?

Accepted Answer

Pollen from one population fertilizes plants in another population

Question 8

In the context of sickle-cell disease, why is the sickle-cell allele maintained at high frequencies in some populations?

Accepted Answer

Heterozygotes have a survival advantage in regions with malaria

Question 9

Which type of selection favors individuals at both extremes of the phenotypic range?

Accepted Answer

Disruptive selection

Question 10

A population of beetles has color variation due to genetic differences. Over time, only the beetles with the darkest color survive and reproduce. Which mechanism is most likely responsible for this change?

Accepted Answer

Natural selection

Question 11

Which equation represents the Hardy-Weinberg equilibrium for a gene with two alleles?

Accepted Answer

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

Question 12

What is the effect of ongoing migration of banded snakes from the mainland to an island population where unbanded snakes are favored?

Accepted Answer

It maintains disadvantageous alleles for banding pattern on the island

Question 13

Which of the following is NOT a source of genetic variation?

Accepted Answer

Natural selection

Question 14

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

Accepted Answer

They will remain constant

Question 15

Which process is most likely to reduce genetic variation among populations over time?

Accepted Answer

Gene flow

Question 16

What is the main difference between intrasexual and intersexual selection?

Accepted Answer

Intrasexual selection involves competition among individuals of one sex, while intersexual selection involves mate choice by the opposite sex

Question 17

Which of the following statements about relative fitness is correct?

Accepted Answer

It is the contribution an individual makes to the gene pool of the next generation relative to others

Question 18

Which mechanism can cause harmful alleles to become fixed in a population?

Accepted Answer

Genetic drift

Question 19

What is the effect of frequency-dependent selection on a population?

Accepted Answer

It maintains stable frequencies of two or more phenotypes

Question 20

Why can't natural selection fashion perfect organisms?

Accepted Answer

Selection can act only on existing variations

Chapter 23: The Evolution of Populations – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards