Whose work first explained how species change by natural selection?

Charles Darwin developed the theory of evolution by natural selection after years of observation, especially from his voyage on HMS Beagle. His major statement came in 1859 with On the Origin of Species. Darwin argued that individuals with advantageous traits are more likely to survive and reproduce, gradually changing populations over time. The idea became one of the central principles of biology. It reshaped our understanding of life on Earth and remains foundational today.