The evolution of languages was not the source of Darwin's theory of evolution. He had based that on variation of species, such as he had observed in finches in the Galapagos Islands, who had appeared to be modifications of a common ancestor. Selection of domestic species to produce a new variety also played a role in his conclusions. The first edition of "Origin of Species" in 1859 discusses the language tree as though "de novo" under the topic of classification. Darwin criticises the synchronic method devised by Linnaeus, suggesting that it be replaced by a "natural arrangement" based on evolution. He says: