Evolution, by definition, is "the process in which significant changes in the inheritable traits of a species or population occur over time" (Biology 12, 2003). Charles Darwin is the founder of the theory of natural selection. This theory is based on the survival of the fittest, and whoever can adapt the best to its environment will survive. Comte Georges Louis de Leclerc Buffon, Jean Baptist Pierre Antoine de Monet, Chevalier de Lamarck, Sir Charles Lyell, Nicholas Steno and Leonardo da Vinci's theories all lend themselves to the belief that evolution is occurring. (Biology 12, 2003).
Comte Georges Louis de Leclerc Buffon's theory states that similar organisms developed from an organism which may have contributed to the development of other organisms. For example, it is believed that human beings developed from primates, so this is a possible common ancestor to human beings (Biology 12, 2003). Jean Baptist Pierre Antoine de Monet, Chevalier de Lamarck's theory suggests that the environment had a role in the development and change of species. He also suggested that species could inherit traits from past generations. For example, a frog that is bright green could mate with a frog that is brown and together could produce frog that is dark green. This is a mutation that was inherited by a new generation, and this mutation could help the frog camouflage itself. This theory helps to forward Darwin's theory about how adaptations to the environment could help a species have a better chance of survival. (Biology 12, 2003).
Sir Charles Lyell developed a theory which states that the "Earth's surface has always changed and continues to change through similar, uniform and very gradual processes" (Biology 12, 2003). This theory is called uniformitarianism. For example, it has been suggested that the continents on Earth used to be as one, and broke apart, and are moving further away their original position as time goes on.