Sunday, March 11, 2012

Yes you DO get loss of genetic diversity with evolution Part 2

Percy again:
Faith writes:
[I'm] constructing an argument to show that selection and isolation single out a particular trait by eliminating all its competition and ultimately make that trait characteristic of a new population that emerges from these processes.
This argument couldn't be more wrong. The alleles for a gene are not involved in a competition where only one is left standing.
Sigh. The main problem seems to be getting it said so that we all at least know what I'm saying. I often use the most extreme example of the point I'm trying to make to indicate the DIRECTION that ALL these processes move in, I'm not trying to hang EVERYTHING on the extreme. Sigh.

It's the PATTERN I'm trying to focus on. Getting a new phenotype, a new variation, a new "species" as evolutionists think of it, REQUIRES that alleles for OTHER (yes, "competing") phenotypes / variations / species be either greatly reduced in the population or eliminated altogether -- the fewer the better for the establishment of the character of the new variation / phenotype / species.
If that were the case then extinction would be an extremely common event because a species ability to survive across changing environmental landscapes is dependent upon variability. Great variability increases the likelihood that at least some subset of a population will survive an environmental change.
Yes, genetic variability IS important for the health of a species, but maintaining genetic variability means NOT EVOLVING. The way you get NEW TRAITS, that is, EVOLUTION, is by isolating the alleles for those traits in their own population and that means ELIMINATING alleles from that population that would bring about different traits. This is how domestic breeding does it and it is also how Nature does it, whether by Natural Selection or Genetic Drift, Bottleneck or a series of population splits over generations with migration and reproductive isolation etc etc etc etc. You won't get a population specifically characterized by green and red striped fur if that population includes individuals that carry alleles for purple and yellow splotched fur.

And such variation does not always threaten extinction although it may at the extremes. However, some animals seem to thrive even with extreme genetic depletion, the elephant seals, even the cheetah does OK considering, etc.
If it were really true that more beneficial alleles eliminate those that are less beneficial or even deleterious then alleles for genetic diseases would have disappeared long ago, and yet genetic diseases like cystic fibrosis persist.
The idea that the alleles must be "beneficial" comes from the Evolution Model. On the contrary, I think accidentally or randomly isolated alleles are probably the more typical foundation for new varieties, they need have no specially "beneficial" properties. They may or may not adapt to a particular niche later. Nature loves variety.

And the alleles that are eliminated still belong to former / other populations /varieties of the same species, it's not as if they died out completely except in some rare extreme cases, it's just that they no longer belong to the population of this new phenotype. The population under discussion may have red and green striped fur while another of the same species has the alleles for purple and yellow blotched fur that would wreck THIS particular variety and vice versa. You don't want Dachshund alleles in the Great Dane breed or vice versa, but alleles for both remain in the dog Species as a whole.
You need to find solutions consistent with both your religious views *and* reality.

Well, I may continue with this attempt to answer objections to my argument here, but just this much dealing with it, even sticking to one antagonist to keep confusion to a minimum, makes it quite clear why I have no interest in being back at EvC. I guess the best construction to put on the problem is that it's a paradigm clash. I'm always talking from my Creationist presuppositions, and although I keep trying to spell those out as I go, the contrary Evolutionist presuppositions are so rigidly held there's little hope of penetrating the fog.

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