Question 1

Which of the following best describes the role of gene flow in the process of speciation?

Accepted Answer

Gene flow reduces genetic differences between populations, often preventing speciation.

Question 2

A population of birds is split by the formation of a river, preventing individuals from crossing. Over time, the two populations develop distinct beak shapes due to different food sources. Which type of speciation is most likely occurring?

Accepted Answer

Allopatric speciation via vicariance

Question 3

Which mechanism is most likely to increase genetic divergence between isolated populations?

Accepted Answer

Genetic drift

Question 4

A plant species undergoes a change in chromosome number, resulting in a new population with double the chromosomes of the original. What is this process called?

Accepted Answer

Polyploidy

Question 5

Which equation best represents the Hardy-Weinberg equilibrium for allele frequencies in a population?

Accepted Answer

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

Question 6

In a scenario where two diverged populations come into secondary contact and hybrids have lower fitness, what evolutionary process is most likely to occur?

Accepted Answer

Reinforcement of reproductive isolation

Question 7

Which of the following is an example of speciation by dispersal?

Accepted Answer

A small group of birds migrates to a new island and forms a new population.

Question 8

If two closely related species of crickets come into contact and produce sterile hybrid offspring, what is the most likely long-term outcome?

Accepted Answer

Extinction of one of the species due to competition

Question 9

Which of the following scenarios best illustrates sympatric speciation?

Accepted Answer

A population of fish develops two distinct mating preferences within the same lake.

Question 10

Which process is most likely to result in the formation of a hybrid species with traits from both parent species?

Accepted Answer

Hybrid speciation

Question 11

A population of frogs is split by a newly formed highway, preventing gene flow. Over generations, the two populations accumulate different mutations. Which evolutionary mechanisms are most likely contributing to their divergence?

Accepted Answer

Mutation, selection, and genetic drift

Question 12

Which of the following is NOT a possible outcome of secondary contact between two diverged populations?

Accepted Answer

Complete loss of genetic variation in both populations

Question 13

In a fish population, disruptive selection favors individuals with either very high or very low gill raker numbers. If gene flow is limited, what is the most likely evolutionary outcome?

Accepted Answer

Speciation into two populations with distinct gill raker numbers

Question 14

Which of the following best explains the founder effect in allopatric speciation?

Accepted Answer

A small group migrates to a new area, and genetic drift causes rapid divergence.

Question 15

If reinforcement is occurring between two species in sympatry, how would you expect their mating calls to compare to those in allopatry?

Accepted Answer

Mating calls would be more different in sympatry.

Question 16

Which of the following is a real-world example of speciation by vicariance?

Accepted Answer

A population of ants is split by a river flooding, isolating them on two islands.

Question 17

Which of the following equations represents the calculation of allele frequency for a dominant allele $$A in a $$population?

Accepted Answer

$$p = \frac{2N_{AA} + N_{Aa}}{2N}$$

Question 18

Which of the following is most likely to occur if two populations with limited gene flow come into contact and hybrid offspring have higher fitness than either parent?

Accepted Answer

Formation of a new hybrid species

Question 19

Which process is most likely to result in the maintenance of two separate species after secondary contact?

Accepted Answer

Reinforcement

Question 20

A hybrid zone forms between two species of warblers. Over time, the zone remains stable and hybrids persist. What does this suggest about the fitness of the hybrids?

Accepted Answer

Hybrids have similar fitness to parent species.

Speciation and Secondary Contact: Mechanisms and Outcomes

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