Charles Darwin is recognized for his work on the theory of evolution by natural selection. His landmark publication, "On the Origin of Species," presented evidence for evolution and proposed how species adapt and change over time. Darwin's observations during his voyage on the HMS Beagle provided critical insights into the diversity of life. His theories challenged established scientific and religious beliefs, initiating profound discussions within biology and society. Darwin's contributions transformed our understanding of life and the interconnectedness of species, shaping modern evolutionary science.