Punctuated equilibrium
From CreationWiki, the encyclopedia of creation science
Punctuated Equilibrium is a theory in evolutionary biology that is in sharp contrast to Darwinian gradualism. It was put forward by Niles Eldredge and Stephen Jay Gould, and was largely prompted by the absence of transitional forms in the fossil record.
Most organisms, according to the geological column model, appear suddenly, then remain unchanged for long periods of time. To explain these general characteristics of the fossil record, punctuated equilibrium was proposed.
The theory states that species can change instantaneously on geologic time scales (i.e thousands of years), compared to millions or tens of millions of years as assumed by gradualism. Rapid species evolution is believed to occur as a result of episodic changes in the environment, such as floods or droughts, which are then followed by long periods of stasis. Because of these sudden environmental changes, species must adapt rapidly (punctuated), but then remain unchanged afterwards for long periods of time (equilibrium).
The chief problem with this theory is its unfalsifiability, as these episodes of rapid evolution are, rather conveniently, supposed to be too rare to be seen happening in the present, and too rapid to leave evidences in the fossil record. Furthermore, by reducing the timeframe where beneficial mutations are allowed to accumulate, the theory destroys whatever plausibility there is left for mutations as the proposed source of genetic information.
Punctuated Equilibrium, not based upon fossil evidence, is an explanation for the lack evidence for universal common ancestry.
Related References
- Punctuated equilibrium by Wikipedia
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