Question 1

Which of the following best describes the relationship between genotype and phenotype in the context of coat color in hamsters, as shown in the images?

Accepted Answer

The genotype determines the phenotype, with dominant alleles masking the effect of recessive alleles.

Question 2

A population of 25 hamsters has a gene pool with 20 copies of allele B and 30 copies of allele b. What is the frequency of allele B in this population? Use the formula $$p = \frac{	ext{number of B alleles}}{	ext{total number of alleles}}.$$

Accepted Answer

$$p = \frac{20}{50} = 0.4$$

Question 3

Which process is responsible for the creation of new alleles in a population, thereby increasing genetic variability?

Accepted Answer

Mutation

Question 4

In a laboratory experiment, bacterial colonies are transferred to dishes containing the antibiotic streptomycin. Only a few colonies grow in each dish, and they appear in the same positions. What does this experiment demonstrate about mutations?

Accepted Answer

Mutations occur spontaneously and are not caused by exposure to antibiotics.

Question 5

Which of the following best explains why genetic drift has a greater effect on small populations than on large populations?

Accepted Answer

Random changes in allele frequencies are more likely to lead to the loss of alleles in small populations.

Question 6

A population bottleneck can lead to which of the following outcomes?

Accepted Answer

A drastic reduction in genetic variation due to a sharp decrease in population size.

Question 7

The founder effect is best illustrated by which scenario?

Accepted Answer

A small group of individuals colonizes a new area, resulting in a gene pool that differs from the original population.

Question 8

Which evolutionary process increases the similarity of different populations by introducing new alleles from one population to another?

Accepted Answer

Gene flow

Question 9

In a cancer treatment scenario, cells resistant to drug A survive and predominate after treatment. When drug B is applied, these resistant cells are eliminated. What evolutionary principle does this illustrate?

Accepted Answer

Natural selection can lead to resistance, but different selective pressures can target different resistant populations.

Question 10

Which of the following is an example of sexual selection?

Accepted Answer

Male peacocks evolving showy tails to attract mates.

Question 11

Which type of natural selection favors individuals with average phenotypes and reduces variation in a population?

Accepted Answer

Stabilizing selection

Question 12

If a population of bighorn sheep evolves larger horns due to males with larger horns winning more fights and mating more often, which evolutionary mechanism is at work?

Accepted Answer

Sexual selection

Question 13

Which of the following best describes disruptive selection?

Accepted Answer

Both extreme phenotypes are favored over the average phenotype, potentially leading to two distinct groups.

Question 14

A population of 1000 individuals has two alleles for a gene: A and a. If the frequency of allele A is 0.7, what is the frequency of allele a? Use the formula $$p + q = 1.$$

Accepted Answer

$$q = 1 - 0.7 = 0.3$$

Question 15

Which process changes genotype frequencies but not allele frequencies in a population?

Accepted Answer

Nonrandom mating

Question 16

Which of the following is a real-world example of a population bottleneck?

Accepted Answer

Northern elephant seals, whose population was reduced to a few individuals, resulting in low genetic diversity.

Question 17

Which of the following statements about genetic drift is correct?

Accepted Answer

It can cause random changes in allele frequencies, especially in small populations.

Question 18

If a population is in Hardy-Weinberg equilibrium, which of the following must be true?

Accepted Answer

Allele frequencies remain constant from generation to generation.

Question 19

Which of the following is NOT a consequence of gene flow?

Accepted Answer

Increases the difference between populations.

Question 20

A population of birds is split by a natural disaster, and the two groups evolve independently. Over time, the allele frequencies in the two groups become very different. Which evolutionary process is most likely responsible for this divergence?

Accepted Answer

Genetic drift

How Populations Evolve: Mechanisms of Evolutionary Change

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