SAT - Biology Subject Natural Selection and Speciation Questions and Answers

Question 1

A population of finches on an isolated island primarily eats small, soft seeds.
After a prolonged drought, the plants that produce these seeds die out, leaving only plants that produce large, hard-shelled seeds.
Which of the following patterns of natural selection is most likely to occur in the finch population?

Accepted Answer

Directional selection

Answer

Stabilizing selection

Answer

Disruptive selection

Answer

Sexual selection

Question 2

Which of the following is an example of a postzygotic reproductive isolating mechanism?

Accepted Answer

The offspring of a horse and a donkey, a mule, is sterile.

Answer

Two species of flowers bloom in different seasons.

Answer

The courtship dance of a male bird is not recognized by a female of a different species.

Answer

The sperm of a sea urchin cannot fertilize the egg of another sea urchin species.

Question 3

The formation of the Grand Canyon separated a single population of squirrels into two isolated groups. Over thousands of years, these two groups evolved into distinct species, the Kaibab squirrel on the north rim and the Abert's squirrel on the south rim. This is an example of:

Accepted Answer

Allopatric speciation

Answer

Sympatric speciation

Answer

Genetic drift

Answer

Punctuated equilibrium

Question 4

In a particular species of snail, snails with very light-colored shells and snails with very dark-colored shells are both camouflaged effectively in their environment of light-colored rocks and dark shadows. However, snails with intermediate-colored shells are easily spotted by predators. This scenario is most likely to result in:

Accepted Answer

Disruptive selection

Answer

Directional selection

Answer

The founder effect

Answer

Stabilizing selection

Question 5

A small group of individuals colonizes a new island. The allele frequencies of this new population are, by chance, very different from the original population. This phenomenon is known as:

Accepted Answer

The founder effect

Answer

Gene flow

Answer

The bottleneck effect

Answer

Natural selection

Question 6

Sympatric speciation is more common in plants than in animals. A primary mechanism for this type of speciation in plants is:

Accepted Answer

Polyploidy

Answer

Geographic isolation

Answer

Behavioral isolation

Answer

Temporal isolation