Posted: Jun 21, 2010 3:25 pm
by David M
Nautilidae wrote:Being one that is more ignorant when it comes to evolution, I do not know which is the favored evolutionary model: punctuated equilibrium or phyletic gradualism.

For those of you who do not know, punctuated equilibrium is the evolutionary model that models species as undergoing very little evolution for long periods of time before suddenly (on evolutionary time-scales, of course) evolving fairly rapidly.

Phyletic gradualism is the model that models new species as coming about gradually with no periods of major evolution. Life evolves gradually.

Which is the favored model and why?


Both are correct as mechanisms.

The evidence shows that some species have evolved gradually until they reach the point of speciation while some species undergo rapid evolution to the point of speciation.

The jury is still out on what the exact balance is but it looks like its somewhere around the 50/50 mark as to whether speciation was a result of gradualism or PE rapid evolution.

It is important to note that Gould etc did not exclude gradualism completely and even Darwin did not propose gradualism as the only way.