The Beagle went to the Galapagos lslands, near the west coast of South America. Darwin studied the birds that lived on the island. He found that the 13 different species of finches there had all descended from the same species of finch from the mainland of south America. The finches had evolved different beaks to eat the different types of foods available to them. Darwin published his book, On the Origin of Species in 1859. The book described the theory of natural selection.