After a drought in 1977, researchers hypothesized that on the Galápagos Island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of the following events is now most likely to occur to finch beaks on this island?
A) evolution of yet larger, deeper beaks over time, until all birds have relatively large, deep beaks
B) evolution of smaller, pointier beaks over time, until all birds have relatively small, pointy beaks
C) increased variation in beak size and shape over time
D) no change in beak size and shape over time

Question

Quizplus · Accepted Answer

With the introduction of a variety of bird seeds by the tourist company, finches with different beak sizes and shapes will have access to food sources best suited for their particular beak type. This could lead to an increase in the variation of beak sizes and shapes over time, as there would be less selective pressure for one particular beak type over another.

After a Drought in 1977, Researchers Hypothesized That on the Galápagos