punctuated equilibrium

noun

1. theory of, Biology. a hypothesis holding that the evolution of species proceeds in a characteristic pattern of relative stability for long periods of time interspersed with much shorter periods during which many species become extinct and new species emerge.

punctuated equilibrium

/ pŭngk′cho̅o̅-ā′tĭd /

1. The theory that new species evolve suddenly over relatively short periods of time (a few hundred to a thousand years), followed by longer periods in which little genetic change occurs. Punctuated equilibrium is a revision of Darwin's theory that evolution takes place at a slow, constant rate over millions of years.
2. Compare gradualismSee Note at evolution

punctuated equilibrium

1. The theory that new species evolve suddenly over brief periods of time, followed by longer periods during which there is no genetic change. Punctuated equilibrium is a revision of Darwin's theory of evolution . ( Compare gradualism and catastrophism .)

Word History and Origins

Origin of punctuated equilibrium¹

Coined by Stephen Jay Gould ( def ) and Niles Eldredge, American biologist and paleontologist (born 1943), in their paper “Punctuated equilibria: an alternative to phyletic gradualism” (1972)