In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?

Question

Quizplus · Accepted Answer

Directional selection would operate on the finch population because the trait for a large bill size, which is adapted for cracking hard seeds, would be favored over the trait for a small bill size, which is adapted for cracking soft seeds. As a result, the frequency of the large-billed birds would increase over time, while the frequency of the small-billed birds would decrease.

In Seedcracker Finches from Cameroon, Small- and Large-Billed Birds Specialize