AP BIOLOGY

Detailed explanation-1: -While visiting the Galapagos in 1835, British naturalist Charles Darwin observed local plants and animals. He became fascinated by species that seemed related to ones found on the mainland-but that also had many physical variations unique to different islands.

Detailed explanation-2: -Darwin noticed that the plants and animals on the different islands also differed. For example, the giant tortoises on one island had saddle-shaped shells, while those on another island had dome-shaped shells. People who lived on the islands could even tell the island a turtle came from by its shell.

Detailed explanation-3: -Darwin’s most important observations were made on the Galápagos Islands (see map in Figure below). This is a group of 16 small volcanic islands 966 kilometers (600 miles) off the west coast of Ecuador, South America.