Evolution, Part Two

[rowyn]

I found an article on the theory of punctuated equilibrium, which it turns out I massively mangled in my previous post on evolution. Or, rather, didn't address at all. What I described as "leap from one species to brand-new species in a single generation" is known as "macromutationism," and has little, if any, following. "Punctuated equilibrium" theorizes that new species evolve from previous species 'quickly' only in the geological sense. "Quick" in this case means mere millenia, five to ten thousand years. Darwin's original theory offered "gradualism", or change in species over millions of years.

Puntuctuated equilibrium fits the facts of the fossil record pretty well, and isn't as unbelieveable as macromutationism. Haven't read enough on it to say whether it's provable or disprovable based on evidence, but it seems to be the basis for useful research, so I'm happier with it. :)

Comments

[prester-scott.livejournal.com]

I'm afraid I really don't find "punctuated equilibrium" any less unbelievable than "macromutationism."

What mechanism causes mobility between major forms in such a short time (whatever "short" means)? Environmental adaptation only? X-rays? Fairy godmothers?

And maybe I just don't understand what I'm reading, but I fail to see how you can make the sweeping generalization "puntuctuated equilibrium fits the facts of the fossil record pretty well" based on that article. The studies quoted appear to be saying that species are stable, not that species mutate into other species over geologically short periods; the latter conclusion still appears to be an assumption based on negative evidence. If gradualism requires that there be 1 million years' worth of transitional forms, but PE only requires 10,000 years' worth, then if you find no transitional forms, PE becomes easier to defend, but that's still a long way from proof.