Charles Darwin was a British naturalist born in 1809 who revolutionized scientific thought with his theory of evolution by natural selection. As a young man, Darwin loved nature and exploring. He went on a five-year voyage around the world on the HMS Beagle where he visited places like the Galapagos Islands. His observations of wildlife on the Galapagos, including different species of finches and tortoises, helped him develop the idea that species adapt over generations to their environments through natural selection. After returning from his voyage, Darwin spent decades researching and writing before publishing On the Origin of Species in 1859, in which he laid out the theory that all life on Earth evolved over time from common ancestors through a process