Punctuated equilibrium

'''Punctuated equilibrium''' is a concept proposed by Stephen Jay Gould and Niles Eldredge in 1972. The basic idea is that evolution over very long time spans tends to be characterized by long periods of equilibrium - where little evolutionary change happens - punctuated by rare moments of rapid changes. It is based on the observation of paleontologists that many basic species can persist for millions of years without any significant morphological changes.

The idea of punctuated equilibrium can hardly be called a theory, because it is only a single idea already captured by the name: the idea that evolution is marked by long periods of evolutionary stability, which is punctuated by rare instances of rapid changes.  Gould and Eldredge proposed nothing more and nothing less. Unfortunately they did not develop any theory which is more complex than this single idea.

== Links ==

* Wikipedia entry for [http://en.wikipedia.org/wiki/Punctuated_equilibrium punctuated equilibrium]
* Scholarpedia entry for [http://www.scholarpedia.org/article/Punctuated_equilibria punctuated equilibrium]

[[Category:Evolutionary Principles]]