AP BIOLOGY

Detailed explanation-1: -Darwin thought that evolution took place over hundreds or thousands of years and was impossible to witness in a human lifetime. Peter and Rosemary Grant have seen evolution happen over the course of just two years. The Grants study the evolution of Darwin’s finches on the Galapagos Islands.

Detailed explanation-2: -Peter and Rosemary Grant are distinguished for their remarkable long-term studies demonstrating evolution in action in Galápagos finches. They have demonstrated how very rapid changes in body and beak size in response to changes in the food supply are driven by natural selection.

Detailed explanation-3: -Natural selection was such a powerful idea in explaining the evolution of life that it became established as a scientific theory. Biologists have since observed numerous examples of natural selection influencing evolution. Today, it is known to be just one of several mechanisms by which life evolves.

Detailed explanation-4: -Alfred Russel Wallace (1823–1913) is famously given credit for discovering, independently of Darwin, natural selection as the process accounting for the evolution of species.

Detailed explanation-5: -Directional selection occurs when one of two extreme phenotypes is selected for. This shifts the distribution toward that extreme. This is the type of natural selection that the Grants observed in the beak size of Galápagos finches.