Punctuated equilibrium

Punctuated equilibrium (pl. punctuated equilibria) is a part of evolutionary theory that states that evolution, particularly speciation, occurs relatively quickly with long periods of little change—equilibria—in between. This theory is one of the proposed explanations of the evolutionary patterns of species as observed in the fossil record, particularly the relatively sudden appearance of new species in a geologically short time period, and the perhaps typical lack of substantial change of species during their existence.

References

• Eldredge, Niles, and Gould, Stephen Jay:"Punctuated equilibria: an alternative to phyletic gradualism" in: T.Schopf (Hrsg.), Models in Paleobiology, 82-115, Freeman, Cooper and Co., San Francisco, (1972); reprinted in: N.Eldredge, Time frames, Princeton Univ.Press, Princeton, N.J., 1985, 2
• Gould, Stephen Jay (1980). The Panda's Thumb, chapter 17. New York: W.W. Norton & Company, Inc.
• Dawkins, Richard (1986). The Blind Watchmaker, chapter 9. New York: W.W. Norton & Company, Inc.
• Darwin, Charles (1872). The Origin of Species (Sixth Edition).