Question

In 2002, Peter and B. Rosemary Grant studied a population of Darwin's finches on one of the Galapagos Islands that feed on seeds of various sizes. After a drought that caused only large seeds to be available to the birds, they found that natural selection favored those birds that had much smaller beaks and bodies. Which of the following processes is the best interpretation of this scenario?

a) genetic drift
b) founder effect
c) microevolution
d) macroevolution
e) bottleneck effect

Answer 1

c) microevolution

Step-by-step explanation:

Microevolution is the change in allelic frequencies within a population over time.

If natural selection favored birds with beaks and small bodies, that means that the frequency of that phenotype (beak and small body) increased while the frequency of birds with body and large beaks decreased.

In this example we see that in the Darwin's finches population, the allelic frequencies - reflected in the phenotype - changed over time as a consequence of the drought.