Chrles Darwin is on a HUGE trip around the world to learn more about evolution. This took him 5 years! He saw how animals were similar and different on the opposite sides of the world, but the most incredible place he explored was the Galapagos Islands.
Darwin saw how different animals on different Islands are all the same species but looked completely different. He saw that turtles have different shells, and sizes. He saw that iguanas in rocky areas had a dark grey color and they had sharper claws to clime slippery rocks, other than the iguanas that lived in rain forests that were green and had smaller claws.
The birds were all the same species but on different parts of the world they all adapted to their own environments and their bodies changed so that they could survive in their world.