The Galapagos Marine Iguanas are supposed to have originally come from South America. The Galapagos Islands are of the coast of South America and they could have swum over on long or pieces of debris. Since then, they have evolved a lot. The lizards now have very long and sharp claws (see 1st photo). They help with climbing up rocks and holding on when big waves come. They have flat snouts and sharp teeth that help them scrape algae off the rocks to eat (see 2nd photo). They have long tails that help them swim and can hold their breath for up to an hour (see 3rd photo). Normally, they only go under for 5 to 10 minutes. They also have the ability to spray salt our their noses (see 4th photo). It is a special gland that rids the bloodstream of salt from the salt water. Often the faces of the iguanas look paler or less colorful because of the salt that accumulates there. Lastly, these iguanas have very dark skin (see 5th photo) that helps them take in heat from the sun, since they are cold-blooded and the water is not only salty, but very chilly.
All these characteristics of the Galapagos Marine Iguanas show their evolution since they arrived from the coast of South America. They have developed sharp claws, teeth, skin and tails that help them survive. This, obviously helped Darwin create his theory of evolution, along with the finches and tortoises.