I have called this principle, by which each slight variation, if useful, is preserved, by the term of Natural Selection.

Charles Darwin

On the Origin of the Species

Authentication Score 2

Original Citation

Darwin, Charles. On the Origin of the Species. London: John Murray, 1859, ch. 3.

Current Citation

Darwin, Charles. The Origin of the Species, edited by William Bynum. Penguin, 2009, ch. 3.