NEET BIOLOGY

Detailed explanation-1: -On various islands, finch species have become adapted for different diets: seeds, insects, flowers, the blood of seabirds, and leaves. The ancestral finch was a ground-dwelling, seed-eating finch.

Detailed explanation-2: -As their name suggests, they feed mostly on Opuntia cacti. When the Opuntia are in flower, the finches feed almost exclusively on pollen and nectar. During other times of the year, they will feed on Opuntia seeds and fruit. They will also feed on a range of other vegetative foods and invertebrates.

Detailed explanation-3: -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-4: -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.

Detailed explanation-5: -Assertion :Darwin’s finches show a variety of beaks suited for eating large seeds, flying insects and cactus seeds. Reason: Ancestral seed-eating stock of Darwin’s finches radiated out from South American mainland to different geographical areas of the Galapagos Islands, where they found competitor for new habitats.