Question

Assertion: Darwin's finches of Galapagos islands have different types of modified beaks according to their food habits.
Reason: Adaptive radiation leads to the development of different functional structures from a common ancestral form.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. The assertion is correct but the Reason is incorrect
D. Both Assertion and Reason are incorrect

Answer 1

Darwin's finches (also known as Galápagos finches) are a group of about 18 species of passerine birds that live on the islands of the Galapagos. Their remarkable diversity in beak form and function is well known. They belong to the Geospizinae subfamily or the Geospizini tribe.

Complete answer:
The birds range in size from 10 to 20 cm in length and weigh from 8 to 38 grams. The warbler-finches are the tiniest, while the vegetarian finch is the largest. The size and shape of their beaks, which are highly adapted to different food sources, are the most significant differences between species. The birds are all of the same colors.
Darwin's Finches Adaptation Drought conditions affect beak depth, which is correlated with body size and the ability to crack larger seeds: plants produce fewer, harder seeds in dry years and more, softer seeds in wet years. During drought years, only larger birds with deeper dives survive.
Adaptive radiation is the process by which one species gives rise to multiple species that exploit different niches. Adaptive radiation is the development of various functional structures from a common ancestral form. The Galapagos finches of Darwin's Island shared common ancestors, but now have different types of modified beaks based on their feeding habits. Finches were divided into six types by Darwin, who distinguished thirteen species.

Thus, the answer is option A, Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

Note: Finch species have adapted to a variety of diets on various islands, including seeds, insects, flowers, seabird blood, and leaves. The ancestral finch was a seed-eating, ground-dwelling bird. There would be a total of 14 species in the Galapagos after the burst of speciation: three ground-dwelling seed-eaters; three cactus-dwelling seed-eaters; and one tree-dwelling and eating seeds; and 7 species of tree-dwelling insect-eaters.