AP BIOLOGY

Detailed explanation-1: -New species arise through a process called speciation. In speciation, an ancestral species splits into two or more descendant species that are genetically different from one another and can no longer interbreed. Darwin envisioned speciation as a branching event.

Detailed explanation-2: -Darwin’s finches are an example of adaptive radiation. On each island, the birds slowly adapted to local conditions over a long period of time, and this led to the formation of one or more finch species found on each island.

Detailed explanation-3: -The phenomenon of adaptive radiation was first observed by Darwin when he travelled to a place called Galapagos Island. There he observed that there were finches with different types of beaks. So, he concluded that all of these inches radiated on the same island from a single ancestor Finch.

Detailed explanation-4: -Grant & Grant (2008) suggest that adaptive radiation of the Darwin’s finches was linked with a change in climate and increased habitat diversity. But if the finch radiation was relatively late and triggered by ecological change, we need to explain why late arrivals like the yellow warbler did not radiate, too.

Detailed explanation-5: -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.