Question 1

Which of the following best describes the biological species concept?

Accepted Answer

A population whose members can interbreed and produce fertile offspring.

Question 2

Which scenario is an example of a prezygotic barrier?

Accepted Answer

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

Question 3

A population of plants undergoes a meiotic error resulting in individuals with four sets of chromosomes ($$4N). $$These plants can only breed with other $$4N$$ individuals. What is this process called?

Accepted Answer

Autopolyploidy

Question 4

Which of the following is most likely to result in allopatric speciation?

Accepted Answer

A river forming and dividing a population of rodents into two isolated groups.

Question 5

Why are polyploidy events more common in plants than in animals?

Accepted Answer

Plants can self-fertilize, allowing polyploid individuals to reproduce.

Question 6

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

Accepted Answer

A horse and donkey produce a sterile mule.

Question 7

In a hybrid zone, what outcome is expected if hybrids have lower fitness than parent species?

Accepted Answer

Reinforcement of reproductive barriers.

Question 8

Which of the following best explains why the fossil record sometimes shows sudden appearances of new species?

Accepted Answer

Punctuated equilibrium, where rapid change occurs in small populations under strong selective pressure.

Question 9

Bread wheat ($$T. aestivum) is an $$example of which speciation process?

Accepted Answer

Allopolyploidy

Question 10

Which of the following is NOT a prezygotic reproductive barrier?

Accepted Answer

Reduced hybrid fertility

Question 11

A population of insects switches from feeding on one plant species to another, resulting in reproductive isolation from the original population. This is an example of:

Accepted Answer

Sympatric speciation

Question 12

Which of the following best describes reinforcement in a hybrid zone?

Accepted Answer

Natural selection increases reproductive barriers, reducing hybrid formation.

Question 13

Which of the following is a likely reason why regions with many geographical barriers have high species diversity?

Accepted Answer

Barriers increase opportunities for populations to diverge and form new species.

Question 14

Which of the following is an example of mechanical isolation?

Accepted Answer

Snails with shells spiraling in opposite directions cannot mate.

Question 15

A hybrid plant is vigorous but sterile due to unpaired chromosomes during meiosis. What is the most likely explanation?

Accepted Answer

The hybrid has an odd number of chromosome sets, leading to abnormal meiosis.

Question 16

Which of the following events would most likely lead to sympatric speciation in animals?

Accepted Answer

A subset of a population switches to a new food source and mates only with others using that source.

Question 17

Which of the following is true about allopolyploidy?

Accepted Answer

It produces new species by combining chromosomes from different species.

Question 18

Which of the following best illustrates the concept of punctuated equilibrium?

Accepted Answer

A species remains unchanged for long periods, interrupted by short bursts of rapid evolution.

Question 19

Which of the following is an example of temporal isolation?

Accepted Answer

Two species of skunks breed at different times of the year.

Question 20

Which of the following statements about hybrid breakdown is correct?

Accepted Answer

Hybrid offspring are viable and fertile in the first generation, but their descendants are weak or sterile.

Speciation and the Origin of Species: Mechanisms and Patterns

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