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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.
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. It is named after Per Bak and Kim Sneppen.
For example, Denis Noble says that using terms and categories of the modern synthesis distorts the picture of biology that modern experimentation has discovered. [91] Proponents therefore claim that the extended synthesis is necessary to help expand the conceptions and framework of how evolution is considered throughout the biological disciplines.
Evolution is the change in the heritable characteristics of biological populations over successive generations. [1] [2] It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. [3]
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]
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 ...
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.
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.