Evolution: Puntuated Equlibrium
Punctuated equilibrium (also called punctuated equilibria) is a theory in evolutionary biology which proposes that most species will exhibit little net evolutionary change for most of their geological history, remaining in an extended state called stasis. When significant evolutionary change occurs, the theory proposes that it is generally restricted to rare and rapid (on a geologic time scale) events of branching speciation called cladogenesis. Cladogenesis is the process by which a species splits into two distinct species, rather than one species gradually transforming into another.[1]
more here - http://en.wikipedia.org/wiki/Punctuated_equilibrium
more here - http://en.wikipedia.org/wiki/Punctuated_equilibrium
More on Punctuated Equilibrium
Punctuated equilibrium is an important but often-misinterpreted model of how evolutionary change happens. Punctuated equilibrium does not:
more here - http://evolution.berkeley.edu/evosite/evo101/VIIA1bPunctuated.shtml
Punctuated equilibrium is an important but often-misinterpreted model of how evolutionary change happens. Punctuated equilibrium does not:
- Suggest that Darwin's theory of evolution by natural selection is wrong.
- Mean that the central conclusion of evolutionary theory, that life is old and organisms share a common ancestor, no longer holds.
- Negate previous work on how evolution by natural selection works.
- Imply that evolution only happens in rapid bursts.
more here - http://evolution.berkeley.edu/evosite/evo101/VIIA1bPunctuated.shtml