Why is Charles Darwin a significant person?

Charles Darwin is most famous for having postulated the framework for modern theory of evolution. His theory successfully united specific observations (such as his famous observations regarding finches) and other suggestions about evolution, such as those of Lamarck. His work, written in the volumes of The Origin of Species, is one of the most significant factors in modern Biology, as he suggested and researched the previously (for the most part) unaccepted notion that organisms change and evolve over time, becoming discernibly different organisms.