Is Punctuated Equilibrium a theory or fact; and what are 2-3 examples of it occurring.?

Question

Some scientists deny that a slow macro-evolution has occurred, but others claim that simple to complex changes occur and has happened fast, in fits and starts. Give some examples of this, in which some of these events have been observed. Thanks.

Answer 1

It's both, sometimes evolution is slow and sometimes it's fast, depending on the environment.  The most well known example is the Cambrian Explosion, where many new species emerged in a short time.  This is exactly what evolution predicts will happen, if you have an environment with many open niches then many new species will rapidly develop to fill them.

Keep in mind that we are talking about geologic timescales here.  'Fast' in these terms still means millions of years.  For example, the Cambrian Explosion took place over a period of ~70 million years.  If the average generational age is 3 months then we're still talking about 280 million generations.

Answer 2

Those are not examples of anything just speculation as with most evolutionary clap trap

Answer 3

A good human example is that the Australopithocines stayed stagnant for 2 million years before their cranial capacity changed to give rise to the Homos.

Answer 4

Punctuated equilibrium is a term invented by Stephen J. Gould and Niles Eldridge to describe the fact that evolution does not run at the same speed all of the time.  For example, following mass extinctions, the rate of evolution is relatively fast because there are new and untapped ecological niches.  Examples of these include the Cambrian explosion, the time following the Permian-Triassic extinction, the time following the Triassic-Jurassic extinction, the time following the Cretaceous-Tertiary mass extinction.