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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.
Milford Howell Wolpoff is a paleoanthropologist and professor of anthropology at the University of Michigan and its museum of Anthropology. He is the leading proponent of the multiregional evolution hypothesis that explains the evolution of Homo sapiens as a consequence of evolutionary processes and gene flow across continents within a single species.
The color codes the age of the species. The Bak–Sneppen model is a simple model of co-evolution between interacting species. It was developed to show how self-organized criticality may explain key features of the fossil record, such as the distribution of sizes of extinction events and the phenomenon of punctuated equilibrium.
Gould argued that punctuated equilibrium challenges the gradual change expected by extrapolationists. In the case of Hominid evolution, there is the evolutionary trend of marked increase in brain size. To Gould, this trend was the result of species sorting, in which species with relatively larger brains were more likely to appear, or to survive.
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.
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]
The word phyletic derives from the Greek φυλετικός phūletikos, which conveys the meaning of a line of descent. [2] Phyletic gradualism contrasts with the theory of punctuated equilibrium, which proposes that most evolution occurs isolated in rare episodes of rapid evolution, when a single species splits into two distinct species, followed by a long period of stasis or non-change.