After the drought of 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 these 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

The reliable feeding stations set up by the tourist company provide a consistent and abundant food source, which reduces selection pressure for larger, deeper beaks to crack tough fruits. As a result, there may be increased variation in beak size and shape over time as different beak types are favored by different seed types available at the feeding stations. This could lead to the emergence of new beak morphologies or the maintenance of existing variation in the population.

After the Drought of 1977, Researchers Hypothesized That on the Galápagos