Charles Darwin is credited for the theory of evolution, which he proposed in his groundbreaking work, "On the Origin of Species," published in 1859. Darwin introduced the concept of natural selection, a mechanism whereby organisms better adapted to their environment tend to survive and produce more offspring. This theory revolutionized the understanding of how species evolve over time, emphasizing the relationship between adaptation and survival. Darwin's ideas, though initially controversial, eventually garnered widespread acceptance and laid the foundation for modern evolutionary biology, impacting various fields beyond science, including psychology and sociology.