AP BIOLOGY

Detailed explanation-1: -Darwin wondered about the changes in shape of bird beaks from island to island. So-called cactus finches boast longer, more pointed beaks than their relatives the ground finches. Beaks of warbler finches are thinner and more pointed than both. These adaptations make them more fit to survive on available food.

Detailed explanation-2: -1: Darwin’s Finches: Darwin observed that beak shape varies among finch species. He postulated that the beak of an ancestral species had adapted over time to equip the finches to acquire different food sources.

Detailed explanation-3: -He noticed that each finch species had a different type of beak, depending on the food available on its island. The finches that ate large nuts had strong beaks for breaking the nuts open. Finches that ate small nuts and seeds had beaks for cracking nuts and seeds.

Detailed explanation-4: -On the Galápagos, finches evolved based on different food sources-long, pointed beaks served well for snatching insects while broad, blunt beaks work best for cracking seeds and nuts.

Detailed explanation-5: -In particular, changes to the size and shape of the beaks have enabled the different species to specialise in different types of food: seeds, insects, cactus flowers and fruits or even bird blood. The Galápagos finches are a classic example of adaptive radiation.