▮ Services. American Geosciences Institute. American Geosciences Institute. Pojeta, J. & Springer, D. A. (2001) Darwin's Revolutionary Theory [Online]. Available: [Accessed: 31/03/2013]. Darwin's Revolutionary Theory (Previous Page || Next Page) Charles Darwin used information from several disciplines in developing his theory of evolution. He was particularly impressed by the amount of variation that occurs within living species, especially in domestic animals, and he spent a great deal of time studying breeding programs. Even in Darwin’s day, the human effort in breeding variants of domestic animals had resulted in many breeds of dogs, cats, horses, sheep, and cattle. As an example, consider the tremendous variation in domestic dogs.
Darwin gathered data and honed his theory for 20 years before publishing his well-known book in 1859, The Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life. Darwin’s theory of evolution can be summarized in four statements. Variation exists among individuals within species. Competition exists among individuals. Some variations are helpful. (Previous Page || Next Page)