Question

Darwin’s finches are an excellent example of
A.Adaptive radiation
B.Seasonal migration
C.Brood parasitism
D.Connecting links

Answer 1

Darwin's finches are also known as the Galapagos finches.
They are a group of around eighteen species of the passerine birds.
They are well known for their remarkable diversity in beak form and the function.

Complete step by step answer:
Darwin's finches are an excellent example of adaptive radiation.
Their common ancestor arrived on the Galapagos about around two million years ago.
During the time that has passed the Darwin's finches have evolved into many recognized species differing in the body size, in the beak shape, the song and the feeding behavior.
Changes in the size and form of the beak have enabled different species to utilize the different food resources such as an insect, the seeds, nectar from the cactus flowers as well as the blood from iguanas, these all driven by Darwinian selection.

Therefore, the correct answer is option A.

Additional information:
Finches have stout conical bills adapted for eating the seeds and the nuts and often have colorful plumage.
They occupy a great range of habitats where they are usually the resident and do not migrate.
They have a worldwide distribution except for Australia and the Polar Regions.
The avian paleontologist David Steadman argued based on the morphological and the behavioral similarities, that the blue-back grassquit Volatinia jacarina, a small tropical bird common throughout much of the Central and the South America, was the most likely direct ancestor of the Galapagos finches.

Note:
On the Galapagos Islands, Darwin observed several species of finches with the unique beak shapes.
He postulated that the beak of an ancestral species had adapted over the period of time to equip the finches to acquire the different food sources.