Based on his own collections and travel notes, following the scientific methodology of the progressive geologist Charles Lyell (who held that the formation of the Earth and its crust was influenced solely by physical and chemical processes, and who rejected all creationist views), Darwin drew conclusions about the changes that species had to undergo in order to survive in a changing natural environment.
At the same time, another British biologist and naturalist, Alfred Russel Wallace, 14 years younger than Darwin, who was conducting research in the Amazon, Malaysia, and Indonesia, came to almost identical conclusions and developed a competing theory of natural selection (Darwin was unaware of this).
