Charles Darwin used the finches to provide evidence for natural selection. He realized that the finches have different beaks because they are adapted to eat different kinds of food. For example, a finch with a big beak is very good at cracking open nuts, and a finch with a long beak is very good at catching insects. Darwin was able to see that the finches had a common ancestor which is why they were so similar except for their beaks. Eventually, this led to the theory of evolution.
- Darwin, Charles (1859), On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life (1st ed.), London: John Murray External link in
- Grant, Peter R.; Grant, B. Rosemary (2008), How and Why Species Multiply: The Radiation of Darwin's Finches, Princeton University Press, ISBN 978-0-691-13360-7
- Sulloway, Frank J. (Spring 1982), "Darwin and His Finches: The Evolution of a Legend" (PDF), Journal of the History of Biology, 15 (1), pp. 1–53, doi:10.1007/BF00132004, retrieved 2008-12-09
- Grant & Grant 2008, p. 3