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View Full Version : Punctuated Equilibrium or Phyletic Gradualism?



The Vegan Marxist
6th April 2011, 01:06
Here we have two very important theories of how evolution works. We all can agree that evolution is an absolute fact! The problem, though, is trying to understand how it exactly works. The popular theory being that of Phyletic Gradualism, it's quite likely this is how evolution really works. Though, popular support does not constitute itself as evidence, per se. Whereas, we have the opposing theory, as laid out by Prof's. Stephen Jay Gould and Niles Eldredge, known as Punctuated Equilibrium.

The difference between the two theories is that:


Phyletic Gradualism (http://en.wikipedia.org/wiki/Phyletic_gradualism): a speciation hypothesis rooted in uniformitarianism. The hypothesis states that species continue to adapt to new environmental and biological selection pressures over the course of their history, gradually becoming new species; and

Punctuated Equilibrium (http://en.wikipedia.org/wiki/Punctuated_equilibrium): a theory in evolutionary biology which proposes that most sexually reproducing species will experience little evolutionary change for most of their geological history (in an extended state called stasis).


Both proponents of PG and proponents of PE have given out great accounts of "proving" their theories are correct. Of course, there still appears to be conflict as to which theory is correct. Both stating that Darwin's work adhere to theirs.

I know Richard Dawkins has proposed Phyletic Gradualism as being the correct theory, as laid out in his work The Blind Watchmaker, where he dedicated an entire chapter on this theory - the chapter being "The One True Tree of Life", which can be located here:

http://www.terebess.com/keletkult/The_Blind_Watchmaker.pdf

Prof's. Stephen Gould and Niles Eldredge had laid out their own work on their proposed theory, Punctuated Equilibrium, which can be located here:

http://www.blackwellpublishing.com/ridley/classictexts/eldredge.pdf

What does everyone else think?

Gorilla
6th April 2011, 01:12
What does everyone else think?

What I was led to believe in my college bio classes, and what I have got from undergrads at the college I used to work at, is basically no one believes punctuated equilibrium anymore.

Ocean Seal
6th April 2011, 01:15
I don't understand why both theories have to be opposing. Its very clear that both are correct in certain respects and that alone each cannot account for evolution so I would think that evolution happens in both ways. Albeit I believe that gradualism is more common.

The Vegan Marxist
6th April 2011, 01:21
I don't understand why both theories have to be opposing. Its very clear that both are correct in certain respects and that alone each cannot account for evolution so I would think that evolution happens in both ways. Albeit I believe that gradualism is more common.

But the main thesis of P.E. is that evolution isn't gradual, and at most is rare, random spurts. Thus, one contradicts the other. I don't think both can correlate together without a major redefining of either or.