Question 1

Which of the following best describes allopatric speciation?

Accepted Answer

A population forms a new species while geographically isolated from its parent population.

Question 2

Which of the following is an example of vicariance leading to speciation?

Accepted Answer

A mountain range forms, splitting a population of squirrels and leading to the evolution of two distinct species.

Question 3

Which process is most likely responsible for the formation of polyploid crops such as wheat and cotton?

Accepted Answer

Sympatric speciation via polyploidy

Question 4

A tetraploid plant (4n) arises from a diploid ancestor (2n) due to a meiotic error. If this tetraploid self-pollinates, what is the expected chromosome number in its offspring?

Accepted Answer

$$4n$$

Question 5

Why are triploid (3n) offspring resulting from a cross between a tetraploid (4n) and a diploid (2n) plant usually sterile?

Accepted Answer

They cannot undergo meiosis properly due to unpaired chromosomes.

Question 6

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

Accepted Answer

Plants can reproduce asexually and self-fertilize, allowing polyploid individuals to establish new populations.

Question 7

Which of the following scenarios is an example of adaptive radiation?

Accepted Answer

A single ancestral bird species colonizes the Galápagos Islands and evolves into multiple species adapted to different niches.

Question 8

Which of the following is a key requirement for speciation to occur?

Accepted Answer

Restriction of gene flow between populations

Question 9

In allopolyploid speciation, what is the source of the multiple sets of chromosomes?

Accepted Answer

Hybridization between two different species followed by chromosome doubling

Question 10

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

Accepted Answer

Natural selection increases reproductive isolation between diverging populations.

Question 11

A population of frogs is split by the formation of a new river, and over time, the two groups evolve into distinct species. Which type of speciation has occurred?

Accepted Answer

Allopatric speciation

Question 12

Which of the following is NOT a mechanism that can lead to reproductive isolation?

Accepted Answer

Increased gene flow between populations

Question 13

Which of the following equations correctly represents the chromosome number in a diploid organism after normal meiosis?

Accepted Answer

$$n$$

Question 14

Bread wheat is an allohexaploid (6n) species. Which process most likely led to its formation?

Accepted Answer

Hybridization between three different species followed by chromosome doubling

Question 15

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

Accepted Answer

Formation of new fish species after a lake splits into two smaller lakes

Question 16

Which of the following statements about sympatric speciation is correct?

Accepted Answer

It can occur through polyploidy in plants.

Question 17

If a diploid plant (2n) produces unreduced gametes due to a meiotic error, and these gametes fuse, what is the chromosome number of the resulting zygote?

Accepted Answer

$$4n$$

Question 18

Which of the following best explains why an uneven number of chromosome sets (e.g., 3n) leads to sterility in plants?

Accepted Answer

Chromosomes cannot pair properly during meiosis, leading to unbalanced gametes.

Question 19

Which of the following is a likely outcome if gene flow is not restricted between two populations?

Accepted Answer

The populations will remain genetically similar and not speciate.

Speciation: Mechanisms and Processes

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