Mutations, bad not good (Introduction)

by Balance_Maintained , U.S.A., Monday, July 18, 2011, 01:13 (4878 days ago) @ dhw

"No one definition has as yet satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species."
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> "Certainly no clear line of demarcation has as yet been drawn between species and sub-species [...] or, again, between sub-species and well-marked varieties, or between lesser varieties and individual differences."
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> "If a variety were to flourish so as to exceed in numbers the parent species, it would then rank as the species, and the species as the variety; or it might come to supplant and exterminate the parent species; or both might co-exist, and both rank as an independent species." (Interesting in the context of the Neanderthals.)
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> This is indeed another problem that has still not been solved, though it doesn't affect the discussion on how the mechanisms of evolution actually work.
> -While I can appreciate that Darwin himself did not try to make a clear demarcation between one species and another, I think that it does affect the discussion. If we have no clear delineation between one species and the next, then how can we even begin to discuss evolution proper as a progressive movement from common ancestor to our current state of variety. At some point, there has to be a cut off between the ability to breed between one group and the next, and the point is critical, and I would say central, to the case of Evolution vs. ID. If such a mechanism does indeed exist, we should be able to isolate it. While it would not, in and of itself, definitively prove one over the other, the lack of such a mechanism would actually prove to be a strong notch in the ID supporters belt. In other words, if we can't prove that evolution, of its own accord, can provide a sustainable variety that is incapable of breeding with its predecessor, or evolutionary cousins, then how do we account for the variety of life which is unable to cross that boundary.-
> DAVID: Since there are no fossil series that show Darwin's tiny gradual steps, I agree that PE is the main mechanism, whatever that means. 
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> I don't see PE as a mechanism at all, but simply a historical description. There are long periods of equilibrium in which species remain relatively stable, and these are punctuated by bursts of activity, with extinctions, innovations etc. These bursts may be associated with major events affecting the environment. Tony questions "how fast these changes are actually able to happen" and wonders why we have not witnessed more of them, "particularly after the drastic changes man has made to the environment". Even the Cambrian Explosion took millions of years (though different sources give wildly varying figures of how many millions). How fast is "fast"? However, if there is a sudden event like, say, a massive eruption or a collision with a meteorite, I would have thought changes would be extremely rapid. Adaptation would certainly need to be swift, but adaptation need not lead to innovations and new species.
> -If a organism took a million years, a thousand years, or even a century, to adapt to an environment suddenly turned hostile, I can not conceive how the species would survive long enough to adapt. To slightly altar your question above, "How fast is fast enough?"-> DAVID: In medicine, if we didn't understand a process, we gave it a name and everyone felt better.
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> A wonderful revelation! But actually it's a very serious point. By naming things, we give them authenticity, authority, and eventually perhaps even familiarity. Think of "random mutations", "dark energy", "multiverse", "God".-Agreed!!