When directional selection persists over time we expect
A) an eventual decrease in genetic variation within the population.
B) an initial response in the population to the new environmental pressure, and then a flattening out of the response after several generations.
C) the population to become adapted to the new environment.
D) all of the above.

Question

Quizplus · Accepted Answer

Directional selection, when persistent, leads to a decrease in genetic variation as alleles that confer a disadvantage are weeded out. Initially, the population adapts to the new environmental pressures, but as the advantageous traits become fixed, the response to selection flattens out. Over time, the population becomes better adapted to the new environment.

When Directional Selection Persists Over Time We Expect