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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.
Punctuated equilibrium is commonly contrasted with phyletic gradualism, the idea that evolution generally occurs uniformly by the steady and gradual transformation of whole lineages . [2] In 1972, paleontologists Niles Eldredge and Stephen Jay Gould published a landmark paper developing their theory and called it punctuated equilibria. [1]
Also, members of older groups tended to perceive their groups to have more of the characteristics of Stage-3 and Stage-4 groups and to be more productive. Based on these results, Wheelan's position supports the traditional linear models of group development and casts doubt on the cyclic models and Gersick's punctuated equilibrium model.
In the 1980s, the American palaeontologists Stephen Jay Gould and Niles Eldredge argued for an extended synthesis based on their idea of punctuated equilibrium, the role of species selection shaping large scale evolutionary patterns and natural selection working on multiple levels extending from genes to species. [30] [31] [32] [33]
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".
The punctuated equilibrium model of policy change was first presented by Frank Baumgartner and Bryan Jones in 1993, [1] and has increasingly received attention in historical institutionalism. [3] The model states that policy generally changes only incrementally due to several restraints, namely the "stickiness" of institutional cultures, vested ...
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 ...
Hugh Falconer MD FRS (29 February 1808 – 31 January 1865 [1]) was a Scottish geologist, botanist, palaeontologist, and paleoanthropologist.He studied the flora, fauna, and geology of India, Assam, Burma, and most of the Mediterranean islands and was the first to suggest the modern evolutionary theory of punctuated equilibrium.