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Wednesday, February 05, 12:54:08pm

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Subject: Rapid?

Author:
Damoclese

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Date Posted: 02/25/03 2:07pm
In reply to: Peter Flickinger 's message, "faith in rapid evolution" on 02/24/03 12:53pm

>You have great faith to conclude that an incredible
>lack of evidence means rapid evolution. It is like
>saying "there is no evidence - so change the theory to
>something where the evidence does not exist - and
>therefore it cannot be proved/disproved".
>

A mountain has been made out of a molehill concering rapid evolution and so called punctuated equilibrium.

Punctuated equilibrium is always contrasted against gradualism, but in actuality punctuated equlibirum is nothing new to gradualism--rather it was intuitvely thought to be a part of gradualism for quite some time.

Under normal circumstances the gradualist will tell you that evolution progresses very slowly. This assumes that the selection pressure isn't horribly high; meaning neither competitors or the environment are such that demand quick adaptation.

But let us suppose a hypothetical example that rarely happens. Let us postulate the existance of a species that fortunately for it has had some mutation in two generations that allow it to compete for resources much more efficiently than some other similar species. Obviously, the other species is going to have to adapt more quickly, or else run the risk of being gradually weeded out. Selection pressure is high. The species must preserve changes that allow it to compete as effectively if not better than the other, or risk becoming a minority or becoming extinct. In this situation, evolution might stop being as gradual, and instead be more rapid--let's say in eight generations the transformation has taken place. Now, this isn't "fast", but it certainly is much "faster" than low pressure evolution might occur.

Is there positive evidence of "rapid" evolution? Sure. You'll note this concerns positive evidence and not absence of evidence. Consider the Pepper moths during the industrial revolution. The environment changed rapidly e.g. smoke stacks and other factories throwing soot into the air. The moths began to become darker in color as white no longer was viable. The frequency in the gene pool changed in a very short amount of time.

The same thing can be demonstrated by bacteria that become resilent to antibiotics. They change, and they change quickly because selection pressure is high.

Now, if something changes quickly, that doesn't mean there won't be any fossils of it. It probably means if anything that there will be fewer fossils of it than something else that took longer to evolve due to the conditions that it takes to fosilize something--the frequency of the number of intermediate creatures will most likely be less, if there are any at all.(preserved)

The case is such that there is positive evidence of rapid change, and negative evidence (gaps in the fossil record) that support this positive result. The two bear down on one another much as any other claim to uphold the notion that evolution given the right conditions, can happen more quickly.

Damoclese

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