theory of evolution whereby changes in species are driven, over time, by natural and sexual selection. He struggled internally with this idea, finally publishing The Origin of Species 20 years after returning from his voyage."/>

1809-1882
From his observations on the Galapagos Islands, Darwin developed the theory of evolution whereby changes in species are driven, over time, by natural and sexual selection. He struggled internally with this idea, finally publishing The Origin of Species 20 years after returning from his voyage.