Charles Darwin is well-known for the theory of natural selection. His groundbreaking work, particularly highlighted in "On the Origin of Species" published in 1859, proposed that species evolve over time through a process where individuals with advantageous traits have a better chance of survival and reproduction. This mechanism of natural selection explains the adaptation of organisms to their environments and is a fundamental principle of evolutionary biology. Darwin's theory revolutionized the understanding of life on Earth, influencing various fields such as genetics, ecology, and conservation biology, and continues to be a cornerstone in the study of evolution.