Charles Darwin is known for developing the theory of evolution. His groundbreaking work, particularly the publication of "On the Origin of Species" in 1859, introduced the concept of natural selection, positing that species evolve over time through a process where those best adapted to their environment survive and reproduce. Darwin's meticulous observations during his voyage on the HMS Beagle led him to formulate ideas about species variation and adaptation. His contributions fundamentally changed how we understand biological diversity and the interconnectedness of life forms on Earth, establishing a foundation for modern evolutionary biology.