The scientist famous for his contributions to genetics and the theory of evolution is Charles Darwin. His groundbreaking work, "On the Origin of Species," published in 1859, introduced the concept of natural selection as a mechanism for evolution. Darwin's meticulous observations and research during his voyage on the HMS Beagle laid the foundation for modern evolutionary biology. His theories challenged established beliefs about species and their origins, ultimately revolutionizing the understanding of the natural world and influencing subsequent scientific study in various fields.