PrepGo

AP Biology Practice Quiz: Population Genetics

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 16 questions to check your progress.

Question 1 of 16

According to the provided text, what is the most direct evidence for the occurrence of evolution in a population?

All Questions (16)

According to the provided text, what is the most direct evidence for the occurrence of evolution in a population?

A) The appearance of new physical traits.

B) Changes in allele frequencies over time.

C) The migration of individuals into the population.

D) The occurrence of a random mutation.

Correct Answer: B

The content explicitly states, 'Changes in allele frequencies over time provide direct evidence for the occurrence of evolution in a population.'

Which of the following is described as the primary source of new genetic variation within a population?

A) Genetic drift

B) Gene flow

C) The bottleneck effect

D) Mutation

Correct Answer: D

The text states that 'Random processes like mutation provide new genetic variation.' This identifies mutation as the source of new variations.

A small group of birds is blown off course during migration and establishes a new colony on a remote island. This new colony's gene pool is significantly different from the original population. This is an example of which evolutionary process?

A) The bottleneck effect

B) Gene flow

C) The founder effect

D) Mutation

Correct Answer: C

The founder effect is a specific type of genetic drift that occurs when a new population is established by a small number of individuals, whose gene pool may differ by chance from the source population. The text lists the founder effect as an example of a random event driving evolution.

Which random process is most likely to cause small, isolated populations to become genetically different from one another over time?

A) Gene flow

B) Genetic drift

C) Stabilizing selection

D) High mutation rates

Correct Answer: B

The provided content states that 'genetic drift can cause small populations to diverge,' meaning they become more different from each other.

What is the fundamental definition of evolution as described in the provided text?

A) The survival of the fittest individuals.

B) The development of complex organisms from simpler ones.

C) The change in the genetic makeup of a population over time.

D) The process by which new species are formed.

Correct Answer: C

The text directly states that evolution can be described as 'the change in the genetic makeup of a population over time.'

A population of Northern elephant seals was hunted to near extinction in the 1890s, with only about 20 individuals remaining. The population has since rebounded to over 30,000, but they have much less genetic variation than the original population. This scenario is a classic example of:

A) The founder effect

B) Migration

C) Gene flow

D) The bottleneck effect

Correct Answer: D

The bottleneck effect, a type of genetic drift, occurs when a population's size is drastically reduced by a random event. The surviving individuals may have allele frequencies that differ from the original population, leading to reduced genetic variation. The text includes the bottleneck effect as a random event that drives evolution.

What is the primary evolutionary role of gene flow between two populations?

A) It increases the rate of mutation.

B) It causes the populations to diverge genetically.

C) It prevents the populations from diverging genetically.

D) It only affects the genetic makeup of very small populations.

Correct Answer: C

The provided text explicitly states that 'gene flow can prevent divergence' between populations by mixing their gene pools.

Which of the following are all described in the text as random events that can drive evolution?

A) Natural selection, mutation, and adaptation

B) Mutation, genetic drift, and gene flow

C) Founder effect, adaptation, and migration

D) Bottleneck effect, natural selection, and mutation

Correct Answer: B

The text states, 'Evolution is also driven by random events such as mutation, genetic drift (including bottleneck and founder effects), and migration/gene flow.' Option B lists three of these key random events.

Two populations of a plant species are located on opposite sides of a large river. Over time, they develop different allele frequencies for flower color. If a bridge is built and pollinators begin to travel between the two populations, what is the most likely long-term effect on their genetic makeup?

A) The two populations will diverge even more rapidly due to the founder effect.

B) The allele frequencies of the two populations will become more similar due to gene flow.

C) Genetic drift will become the dominant evolutionary force in both populations.

D) The rate of mutation will increase, creating new flower colors.

Correct Answer: B

The movement of pollinators facilitates migration/gene flow between the populations. According to the text, 'gene flow can prevent divergence.' Therefore, the exchange of alleles will make the populations more genetically similar over time.

How do random occurrences, such as genetic drift, impact the evolution of specific populations?

A) They always increase the genetic variation within a population.

B) They ensure that populations become better adapted to their environment.

C) They can cause changes in the genetic makeup of a population by chance.

D) They prevent new mutations from appearing in the gene pool.

Correct Answer: C

The content explains that random occurrences affect the genetic makeup of a population and that random processes like genetic drift drive evolution. These changes are due to chance, not adaptation.

A scientist is studying a large, stable population of squirrels where migration is rare. After several years, she finds that the allele frequencies for a specific gene have not changed. Based on the provided text, what is the most valid conclusion?

A) Evolution is not occurring in this population with respect to that gene.

B) The mutation rate in the population is extremely high.

C) Genetic drift is causing the population to diverge.

D) The population is experiencing a strong bottleneck effect.

Correct Answer: A

The text defines evolution as 'the change in the genetic makeup of a population over time' and states that 'Changes in allele frequencies over time provide direct evidence for the occurrence of evolution'. If allele frequencies are not changing, then evolution is not occurring for that trait.

The founder effect and the bottleneck effect are both specific examples of what broader evolutionary mechanism?

A) Mutation

B) Gene flow

C) Genetic drift

D) Natural selection

Correct Answer: C

The text explicitly groups these concepts together: '...genetic drift (including bottleneck and founder effects)...'

In which of the following populations would the effects of genetic drift be most pronounced?

A) A large population of 1,000,000 insects with frequent migration.

B) A small, isolated island population of 50 birds.

C) A medium-sized population of 10,000 fish in a large lake.

D) A continental population of 5,000,000 mammals.

Correct Answer: B

The text states that 'genetic drift can cause small populations to diverge.' This implies that the effects of random chance (genetic drift) are magnified in smaller populations.

The movement of alleles into or out of a population due to the movement of fertile individuals or their gametes is known as:

A) Mutation

B) The bottleneck effect

C) Genetic drift

D) Migration/gene flow

Correct Answer: D

The text identifies 'migration/gene flow' as a random event that drives evolution. This process involves the transfer of genetic material from one population to another.

A population of wildflowers has two alleles for petal color, red (R) and white (r). A researcher finds that the frequency of the R allele is 0.7 in one generation and 0.5 in the next generation. What does this change directly demonstrate?

A) The population is not subject to random processes.

B) The occurrence of evolution.

C) The population is in genetic equilibrium.

D) A complete lack of gene flow.

Correct Answer: B

The content states that 'Changes in allele frequencies over time provide direct evidence for the occurrence of evolution in a population.' The shift in the R allele frequency from 0.7 to 0.5 is a direct example of this.

Which statement accurately describes the relationship between random processes and evolution based on the provided text?

A) Random processes are the only force that drives evolution.

B) Random processes, such as mutation and genetic drift, are drivers of evolution.

C) Random processes always lead to populations becoming more adapted to their environment.

D) Random processes only occur in the absence of gene flow.

Correct Answer: B

The text clearly states that 'Evolution is also driven by random events such as mutation, genetic drift... and migration/gene flow.' This confirms that random processes are a key component in driving evolutionary change.