Whose theory explained natural selection?

Charles Darwin is credited with explaining natural selection as the main mechanism of evolution. He published his landmark book On the Origin of Species in 1859 after years of research and observation, including evidence from his voyage on HMS Beagle. Darwin showed how heritable variations that help organisms survive and reproduce can become more common over generations. Alfred Russel Wallace independently reached a similar conclusion, and both men were presented jointly in 1858 by the Linnean Society of London. Darwin's work transformed biology and remains central to modern evolutionary science.