Charles Darwin is known for creating the theory of evolution. His groundbreaking work, particularly the publication of "On the Origin of Species" in 1859, introduced the concept of natural selection, which explains how species adapt and evolve over time through the survival of the fittest. Darwin's observations during his voyage on the HMS Beagle, particularly in the Galápagos Islands, led him to develop his ideas about variation and adaptation in species. His theory fundamentally changed the understanding of biology and laid the foundation for modern evolutionary science, influencing various fields from genetics to ecology.