punctuated equilibrium

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punctuated equilibrium

the theory that evolutionary change has occurred during short periods of rapid change punctuated by periods of stability Such a process would be characterized by the absence of an infinite range of intermediate forms, and supporters of the theory point to the vertebrate fossil record as evidence.
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Some of Gould's key writings on these issues include: Stephen Jay Gould and Niles Eldredge, "Punctuated Equilibria: The Tempo and Mode of Evolution Reconsidered," Paleobiology 3 (1977): 115-51; S.
For example, Darwin's original theory of evolution--involving gradual speciation over great expanses of time--has been modified to the new view of punctuated equilibria. This view is that new species evolve rapidly (in geological terms) and then remain stable for much longer periods of time.
Gould's fascination with these topics reflects his theory of "punctuated equilibrium," which maintains that rapid moments of evolutionary change are punctuated by extended periods of relative stasis; see Gould and Niles Eldridge, "Punctuated Equilibria: An Alternative to Phyletic Gradualism," in Models in Paleobiology, ed.
Natural scientists such as Stephen Jay Gould and Nils Eldredge have discovered through the study of fossil records that, contrary to Darwin, species adapt to changing environments not at a constant, gradual rate, but through a series of so-called "punctuated equilibria." That is, species mutate in brief spurts during sudden, revolutionary "punctuations" of rapid change, followed much longer by periods of slower changing "equilibrium."
Theory and explanation, patterns and trends, economic and social theory, punctuated equilibria, and gradualism and spatial inequality are among his perspectives.
His theory of punctuated equilibria is paraded out; its postulation of rapid change between periods of nonactivity is taken as evidence of evolutionists' problems with the paths of evolution; and then all is wrapped up as a supposedly devastating critique of the very fact of evolution.