Sir Charles Lyell, 1st Baronet, was a Scottish geologist who demonstrated the power of known natural causes in explaining the earth's history. He is best known today for his association with Charles Darwin and as the author of Principles of Geology (1830–33), which presented to a wide public audience the idea that the earth was shaped by the same natural processes still in operation today, operating at similar intensities. The philosopher William Whewell dubbed this gradualistic view "uniformitarianism" and contrasted it with catastrophism, which had been championed by Georges Cuvier and was better accepted in Europe. The combination of evidence and eloquence in Principles convinced a wide range of readers of the significance of "deep time" for understanding the earth and environment.

Charles Robert Darwin was an English naturalist, geologist and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental concept in science. In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history and was honoured by burial in Westminster Abbey.