Charles Darwin is an important figure in Evolution but it is important to remember that he did not originate the idea. The theory of Evolution began much earlier with early philosophers speculating on the similarities of animal life.
Darwin was influenced by these ideas, starting with his Grandfather who wrote about the origin of life. As a young adult, he was a member of the Plinian Society and a friend to its founder, Robert Grant. At these meetings, university biology students met to discuss evolutionary ideas. They opposed Creationism.
Darwin was not an impartial observer. He had faith in Evolution even before he stepped on the Beagle.
The Theory of Evolution by Cynthia L. Mills
Charles Darwin: The Autobiography of Charles Darwin
Discussing Creationism: The Initial Argument
Part II: Two Questions about the Ark
Part III:The Volume of the Ark
Part IV: The Weight and Sturdiness of the Ark
Part V:What is a Myth
Part VI: Gilgamesh
Part VII: The Biblical View of Noah
Part VIII: Gathering of the Animals
Part IX Evolution
Part X The First Evolutionist
Part XI The Notebook
Part XII Erasmus Darwin
Part XIII Aristotle
Part XIV Middle Ages
Part XV Kant's Quotation
Part XVI Kant in Context