NEET BIOLOGY

Detailed explanation-1: -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-2: -Visitors don’t land on the island so much as they leap to it, jumping from a small boat onto a tiny ledge. In the Galápagos, the Grants studied Charles Darwin’s finches for 40 years.

Detailed explanation-3: -The Grants found changes from one generation to the next in the beak shapes of the medium ground finches on the Galápagos island of Daphne Major. The medium ground finch feeds on seeds. The birds have inherited variation in the bill shape with some individuals having wide, deep bills and others having thinner bills.

Detailed explanation-4: -To show that beaks really do evolve by natural selection, the Grants focused their attention on a desolate island called Daphne Major, where medium ground finches split their time eating big hard spiked seeds, or small soft seeds. They measured the size of beaks on all the finches from one generation to the next.

Detailed explanation-5: -The Grants found that the offspring of the birds that survived the 1977 drought tended to be larger, with bigger beaks. So the adaptation to a changed environment led to a larger-beaked finch population in the following generation.