Question 1

Which of the following best describes allopatric speciation?

Accepted Answer

Speciation that occurs when populations are separated by a physical barrier, leading to genetic divergence.

Question 2

According to the biological species concept, which of the following is the primary criterion for defining a species?

Accepted Answer

Ability to interbreed and produce viable, fertile offspring.

Question 3

A river changes course and splits a population of rodents into two groups. Over time, these groups evolve independently. This is an example of which process?

Accepted Answer

Vicariance

Question 4

Which of the following is a postzygotic reproductive barrier?

Accepted Answer

Hybrid offspring are sterile and cannot reproduce.

Question 5

Which scenario best illustrates sympatric speciation?

Accepted Answer

A population of insects evolves to feed on a new plant species within the same geographic area, leading to reproductive isolation.

Question 6

Which of the following is a limitation of the morphological species concept?

Accepted Answer

It cannot distinguish between cryptic species that look similar but are genetically distinct.

Question 7

A hybrid zone is best described as:

Accepted Answer

A geographic area where interbreeding occurs and hybrid offspring are common.

Question 8

Which of the following outcomes is most likely if hybrid offspring have lower fitness than either parent species?

Accepted Answer

Reinforcement, leading to increased reproductive isolation.

Question 9

Which equation best represents the probability ($$P) of $$two populations diverging due to genetic drift, given a mutation rate ($$\mu) $$and number of generations ($$t$$)?

Accepted Answer

$$P = 1 - e$$^{-2\mu t}$$

Question 10

Which of the following is an example of a prezygotic isolating mechanism?

Accepted Answer

Two species of frogs breed in different seasons, preventing mating.

Question 11

In the phylogenetic species concept, a species is defined as:

Accepted Answer

The smallest monophyletic group on a phylogenetic tree.

Question 12

Which of the following best explains why polyploidy can lead to instant speciation in plants?

Accepted Answer

Polyploid individuals are reproductively isolated from the parent population due to differences in chromosome number.

Question 13

If two populations come into secondary contact and hybrids have equal fitness to parent species, what is the most likely outcome?

Accepted Answer

Fusion of the two populations into a single species.

Question 14

Which of the following is NOT a criterion used by the biological species concept?

Accepted Answer

Morphological similarity

Question 15

A botanist discovers two populations of plants that look identical but do not interbreed in nature. Which species concept would most likely consider them separate species?

Accepted Answer

Biological species concept

Question 16

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

Accepted Answer

The formation of the Isthmus of Panama separating marine organisms into Atlantic and Pacific populations.

Question 17

Which of the following best describes reinforcement in the context of speciation?

Accepted Answer

Natural selection increases reproductive isolation between populations when hybrids have low fitness.

Question 18

Which of the following is a limitation of the phylogenetic species concept?

Accepted Answer

It requires extensive genetic data and well-resolved phylogenies.

Question 19

Which of the following is an example of a postzygotic barrier in humans?

Accepted Answer

A mule, the offspring of a horse and a donkey, is sterile.

Question 20

Which process is most likely to result in adaptive radiation?

Accepted Answer

A single ancestral species colonizes a new environment with many available ecological niches.

Speciation: Mechanisms and Concepts (Ch. 24)

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