Question

The medium ground finch lives on the Galapagos Islands. Birds with beaks of all sizes were originally part of this population. The finches are seed eaters. The types of food available for them to eat depends on the weather. During wet years, there is a large variety of food. During dry years, there is less food, and large, tough seeds are more abundant than small seeds.

After a long drought, researchers noticed certain differences in the population of medium ground finches living compared to those who lived before the drought. What was different about the finches after the drought?
A.
They were smaller.
B.
They had larger beaks.
C.
They had larger wings.
D.
They were a new species.

Answer 1

B. They had larger beaks.

Explanation: The drought reduced food variety and left mostly large, tough seeds. Finches with larger, stronger beaks were better able to eat those seeds and survive/reproduce, so the population shifted toward larger beak size (directional selection).