AP BIOLOGY

Detailed explanation-1: -Darwin noticed that different tortoise species lived on islands with different environments. He realized that the tortoises had traits that allowed them to live in their particular environments. For example, tortoises that ate plants near the ground had rounded shells and shorter necks.

Detailed explanation-2: -One key observation Darwin made occurred while he was studying the specimens from the Galapagos Islands. He noticed the finches on the island were similar to the finches from the mainland, but each showed certain characteristics that helped them to gather food more easily in their specific habitat.

Detailed explanation-3: -All subspecies of Galápagos tortoises evolved from common ancestors that arrived from mainland South America by overwater dispersal. Genetic studies have shown that the Chaco tortoise of Argentina and Paraguay is their closest living relative.

Detailed explanation-4: -His discoveries included four different species of giant ground sloth (some of the largest land mammals ever to have lived), a gomphothere and the remains of an extinct horse. Many of Darwin’s fossils survive, at the Museum and elsewhere.

Detailed explanation-5: -The most studied animals on the Galápagos are finches, a type of bird (Figure below). When Darwin first observed finches on the islands, he did not even realize they were all finches. But when he studied them further, he realized they were related to each other. Each island had its own distinct species of finch.