Question 1

Which of the following best explains how sexual selection contributed to the speciation of Pundamilia nyererei and Pundamilia pundamilia in Lake Victoria?

Accepted Answer

Sexual selection led to differences in coloration, which caused females to preferentially mate with males of their own species, reinforcing reproductive isolation.

Question 2

What is adaptive radiation, and which of the following is a classic example of this process?

Accepted Answer

Adaptive radiation is the evolution of many diverse species from a common ancestor; the Galápagos finches are a classic example.

Question 3

Why are isolated islands often sites of speciation?

Accepted Answer

Isolation prevents gene flow, allowing populations to diverge and adapt to unique environments, leading to speciation.

Question 4

During the severe drought in the Galápagos in the 1970s, what evolutionary change was observed in the finch population?

Accepted Answer

The average beak depth increased because only finches with larger beaks could crack the tough seeds that remained.

Question 5

Which of the following best describes a hybrid zone?

Accepted Answer

A region where populations of different species meet and mate, producing some hybrid offspring.

Question 6

What is the main difference between the punctuated equilibrium model and the gradual model of speciation?

Accepted Answer

Punctuated equilibrium involves rapid changes during speciation followed by long periods of stability, while the gradual model involves slow, continuous change.

Question 7

If reinforcement occurs in a hybrid zone, what is the expected outcome?

Accepted Answer

Reproductive barriers are strengthened, reducing the production of hybrids.

Question 8

Which scenario best illustrates the concept of adaptive radiation?

Accepted Answer

A single ancestral bird species colonizes an island chain and evolves into multiple species with different beak shapes adapted to different food sources.

Question 9

Which of the following is a likely consequence if gene flow increases between two previously isolated populations?

Accepted Answer

The populations may fuse, reversing the speciation process.

Question 10

A researcher observes that two closely related fish species in a lake have distinct coloration and rarely interbreed, even when living in the same area. What evolutionary process most likely explains this observation?

Accepted Answer

Sexual selection for different male coloration has reinforced reproductive isolation.

Question 11

Which of the following equations best represents the relationship between the abundance of edible seeds ($$A) $$and the seed toughness index ($$T) $$during the Galápagos drought, based on the provided data?

Accepted Answer

$$A$$ decreases as $$T$$ increases during drought conditions.

Question 12

Which of the following statements about the tempo of speciation is correct?

Accepted Answer

Speciation can occur over a few thousand years or take tens of millions of years, depending on the evolutionary model.

Question 13

Which of the following best describes reinforcement in the context of hybrid zones?

Accepted Answer

It is the strengthening of reproductive barriers, reducing hybrid formation.

Question 14

In the context of speciation, what does the term 'fusion' refer to?

Accepted Answer

The merging of two species into one due to increased gene flow.

Question 15

Which of the following is NOT a requirement for adaptive radiation to occur on isolated islands?

Accepted Answer

Constant gene flow between all populations on the islands.

Question 16

A population of finches with an average beak depth of 9.5 mm in 1976 increased to 10.2 mm by 1978. What selective pressure most likely caused this change?

Accepted Answer

A drought that favored finches with larger beaks capable of cracking tougher seeds.

Question 17

Which of the following best explains why hybrid zones are useful for studying reproductive isolation?

Accepted Answer

They allow scientists to observe the outcomes of interbreeding between closely related species.

Speciation: Mechanisms, Evidence, and Patterns

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