Question 1

Which of the following best describes the biological species concept?

Accepted Answer

A species is a group of populations whose members can interbreed and produce viable, fertile offspring.

Question 2

Which of the following is an example of a prezygotic barrier?

Accepted Answer

Temporal isolation between spotted skunks that breed in different seasons.

Question 3

A population of frogs is separated by a newly formed river, preventing gene flow. Over time, the two populations diverge genetically. What type of speciation is this?

Accepted Answer

Allopatric speciation

Question 4

Which process is most likely responsible for the rapid speciation observed in Darwin’s finches on the Galápagos Islands?

Accepted Answer

Genetic drift following dispersal (founder effect)

Question 5

Which of the following scenarios best illustrates sympatric speciation?

Accepted Answer

Apple and hawthorn flies in the same geographic area develop preferences for different fruits, leading to reproductive isolation.

Question 6

Which equation represents the change in allele frequency due to genetic drift in a small population?

Accepted Answer

$$\Delta p = \frac{1}{2N}$$

Question 7

Polyploidy is a common mechanism of speciation in plants. If a diploid plant (2N) undergoes self-fertilization and produces a tetraploid offspring (4N), what is the likely outcome if the tetraploid mates with a diploid?

Accepted Answer

The offspring will be nonviable or infertile due to uneven chromosome numbers.

Question 8

Which of the following is NOT a possible outcome when two species interbreed and form a hybrid zone?

Accepted Answer

Extinction, where both parent species disappear immediately.

Question 9

A mule is the offspring of a horse and a donkey. Mules are generally sterile. Which type of reproductive barrier does this illustrate?

Accepted Answer

Postzygotic barrier: reduced hybrid fertility

Question 10

Which species concept would be most useful for identifying cryptic species that are morphologically similar but genetically distinct?

Accepted Answer

Phylogenetic species concept

Question 11

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

Accepted Answer

The closing of the Isthmus of Panama separating snapping shrimp populations.

Question 12

Which of the following best explains why sympatric speciation via polyploidy is more common in plants than in animals?

Accepted Answer

Plants can self-fertilize and tolerate changes in chromosome number more easily.

Question 13

Which pattern of speciation is illustrated by the following scenario: Fossil evidence shows a species remains unchanged for millions of years, then rapidly diverges into several new species within a short time frame.

Accepted Answer

Punctuated equilibrium

Question 14

Which of the following is an example of a mechanical isolation barrier?

Accepted Answer

Left-handed and right-handed snails cannot physically align to mate.

Question 15

If two populations of birds are separated by a mountain range and cannot interbreed, which equation would you use to model the probability of gene flow between them?

Accepted Answer

$$m = 0$$

Question 16

Which of the following statements about hybrid zones is correct?

Accepted Answer

Hybrid zones can persist over time, with hybrids continually produced.

Question 17

Which of the following is a postzygotic barrier that results in offspring with low fitness?

Accepted Answer

Hybrid inviability

Question 18

Which of the following would most likely lead to reinforcement in a hybrid zone?

Accepted Answer

Hybrids have lower fitness than parent species.

Question 19

Which of the following is NOT a mechanism by which genetic isolation can occur?

Accepted Answer

Random mating within a single population

Question 20

Which of the following best describes the ecological species concept?

Accepted Answer

A species is defined by its unique role or niche in the environment.

Speciation: Mechanisms, Barriers, and Patterns of Species Formation

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