The famous scientist whose ideas led to the theory of evolution is Charles Darwin. His seminal work, "On the Origin of Species," published in 1859, introduced the concept of natural selection as the mechanism by which species evolve over time. Darwin's observations during his voyage on the HMS Beagle provided him with critical insights into the diversity of life and the adaptation of organisms to their environments. Although Darwin faced considerable opposition from religious and scientific communities, his theories fundamentally transformed biology, offering a scientific explanation for the complexity of life and the interrelationships among species, shaping modern scientific thought.