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In evolutionary biology, punctuated equilibrium (also called punctuated equilibria) is a theory that proposes that once a species appears in the fossil record, the population will become stable, showing little evolutionary change for most of its geological history. [1] This state of little or no morphological change is called stasis.
Sample of Bak–Sneppen model evolution: on the x-axis the population status, on the y-axis (from top to the bottom) the history of the population. Each discontinuity represents an evolution. The color codes the age of the species.
Eldredge and Stephen Jay Gould proposed punctuated equilibria in 1972. Punctuated equilibrium is a refinement to evolutionary theory. It describes patterns of descent taking place in "fits and starts" separated by long periods of stability. Eldredge went on to develop a hierarchical vision of evolutionary and ecological systems. Around this ...
According to Gould, punctuated equilibrium revised a key pillar "in the central logic of Darwinian theory." [17] Some evolutionary biologists have argued that while punctuated equilibrium was "of great interest to biology generally," [42] it merely modified neo-Darwinism in a manner that was fully compatible with what had been known before. [43]
Jonathan Weiner's The Beak of the Finch describes this very process." (p. 96) Sterelny notes that despite the fact that the fossil record represents, for several reasons, a biased sample, "the consensus seems to be shifting Gould's way: the punctuated equilibrium pattern is common, perhaps even predominant".
English: Alternative explanations of the punctuated equilibrium pattern of evolution observed in the fossil record. Both macromutation and relatively rapid episodes of gradual evolution by natural selection could give the effect of apparently instantaneous change, since 10,000 years barely registers in the fossil record.
Evolutionarily stable strategies were defined and introduced by John Maynard Smith and George R. Price in a 1973 Nature paper. [2] Such was the time taken in peer-reviewing the paper for Nature that this was preceded by a 1972 essay by Maynard Smith in a book of essays titled On Evolution. [1]
The theory of punctuated equilibrium developed by Stephen Jay Gould and Niles Eldredge and first presented in 1972 [61] is often mistakenly drawn into the discussion of transitional fossils. [62] This theory, however, pertains only to well-documented transitions within taxa or between closely related taxa over a geologically short period of time.