punctuated equilibrium

noun

: evolution that is characterized by long periods of stability in the characteristics of an organism and short periods of rapid change during which new forms appear especially from small subpopulations of the ancestral form in restricted parts of its geographic range

also : a theory or model of evolution emphasizing this compare gradualism sense 2

Examples of punctuated equilibrium in a Sentence

Recent Examples on the Web

Evolutionary biologist Stephen Jay Gould once argued that the history of life isn’t simply a gradual change in organisms, but punctuated equilibrium: Long, relatively stable periods give way to rapid speciation after some dramatic event flushes away many of Earth’s existing species. —Eliot Schrefer, Discover Magazine, 11 Aug. 2020

Be it punctuated equilibrium, symbiogenesis, or epigenetics. —Razib Khan, Discover Magazine, 28 Aug. 2011

The idea, called punctuated equilibrium, was originally developed by paleontologists to explain patterns in the emergence and diversification of new species, which sometimes seems to happen in sudden bursts of activity after eons of stability. —Kiona N. Smith, Ars Technica, 20 Sep. 2019

Word History

First Known Use

1972, in the meaning defined above

Rhymes for punctuated equilibrium

• disequilibrium
• nonequilibrium