In 1835 Charles Darwin arrived at the Galapagos islands. He was amazed at what we was seeing.
He was seeing variations of animals. Giant Tortoise, Lizards, and variations of insects. He create a theory called evolutions. he was notcing differences in each animals.
I wonder why...
Darwin noticed how the claw looked on a sloth and how the birds had different size wings. He saw bones of extincted animals and wondered why they were extincted. Over time, he called this natural selection. People were able to notice animals because of there variations, and Darwin's discoveries.