Question

A scientist wrote a paper titled “Directional Selection in Action” after observing a population of mice for 15 years. The mice typically preferred to eat berries, although a few would also eat insects. After a drought in year 3, the scientist observed that more mice were eating insects. By year 10, most of the mice in the population ate insects in addition to berries. Which best describes her article?
Her title is accurate because two opposite extremes are favored.
Her title is accurate because one extreme is favored.
She should change her title because she is observing stabilizing selection.
She should change her title because she is observing disruptive selection.

Answer 1

Her title is accurate because one extreme is favored.

Explanation: the population’s mean diet shifted toward insect-eating after the drought — a change in one direction — which is characteristic of directional selection (selection favoring one extreme phenotype).