The renowned scientist who proposed the theory of evolution through natural selection is Charles Darwin. His groundbreaking work, "On the Origin of Species," published in 1859, laid the foundation for modern evolutionary biology. Darwin's theory postulates that species evolve over time through a process of natural selection, where traits that enhance survival and reproduction are passed down through generations. This theory challenged traditional views on creation and ignited significant debate in the scientific and religious communities. Darwin's meticulous observations during his voyage on the HMS Beagle and his subsequent research provided compelling evidence for the gradual evolution of species.