>Ahhh...gotcha. That is indeed an interesting question. I'm not sure >what the answer is. I know that many new functions are co-opted from >similar functions (I think the classical example is some enzyme >beginning with the letter l...but can't remember right now). But that >begs the question of where the co-opted behaviors came from.
True, and I think also the important issue is how this new function arose from a similar function. The evolution, and natural selection, of classes of beta-lactamases are the examples I know. While we haven't observed it, the early beta-lactamases are hypothesised to have arisen from cell-wall enzymes and the bacteria were facing an enemy in nature (beta-lactams in fungi). Today, we have artificial beta-lactams that are not seen anywhere in nature, yet there are bacteria resistant to it. One explanation that this new function /arose/ (evolved) in the the last few decades, compared to the initial ones, which might've been around for thousands of years and then were selected for when we first developed beta-lactams? Or maybe the genes were already present for all classes of beta-lactams?
I think natural selection is a very strong theory. Evolution, on the other hand, poses interesting questions (like the ones above).
On further thoughts, I think there are two definitions of evolution (at least). Evolution, as a subject, refers to the entire process: arising of function, and natural selection. That is, how a species evolves over time. Evolution can also simply refer to the arising of new function.
>I have seen the new evidence supporting some Lamarkian mechanism, so >your last question does merit some investigation.
Yes, there're some papers in Nature about adaptive mutation I read a while ago.
Also, relevant to this is the mechanism of antibody formation. That's basically evolution and natural selection in our bodies.
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