Posted on 08/21/2006 6:57:26 AM PDT by PatrickHenry
Were the Theory of Evolution even remotely like the grotesque caricature presented by various creationist and intelligent design websites, there would be no debate. It is pernicious that one of the most elegant works of science should be so routinely misrepresented. Before one can evaluate a theory's merits, he is obliged to at least understand what it actually does -- and does not -- state. Failing to understand something before attempting debate against it is absolute folly. Therefore, we offer the following:
1. In every generation, some individuals of a species fail to reproduce. Whether due to biological inadequacy or other mishap, their genetic material is dropped from the species' gene pool. Each new generation is the product of only those individuals that reproduce successfully. ("Success" is a relative term; differential success, like failure, can effect the genetic future of a species.)
2. By eliminating the genetic material of unsuccessful individuals and preserving the rest, nature imposes a filter -- successful reproduction -- on the genetic material of all living things. Because each generation is the result of this filter, the "genetic inventory" of each generation always differs from the one before it. Creationists call this "micro evolution." Please note: individuals never change; they either reproduce or they don't. It's the genetic inventory of a species that changes over time.
3. Mutations occur with virtually every act of reproduction. All genetic material, whether mutated or precisely copied, is subject to nature's filter. If a mutation is neutral or beneficial, or maybe not too harmful, it can endure as part of that species' genetic inventory; otherwise it's filtered out. Mutations that were originally neutral may turn out to be useful or harmful due to changing environmental circumstances, and will be filtered accordingly. If useful, a mutated characteristic can become prevalent within a few generations, and may seem to have wondrously appeared in response to an environmental challenge. In reality, a previously irrelevant feature has become advantageous.
4. Severe environmental changes can enhance the filter's effect, by eliminating numerous individuals that have become inadequate, leaving relatively few individuals whose genetic material will determine the species' future. This will cause rapid changes in the species' genetic inventory. Over thousands of generations, the genetic inventory of a species can become so changed that, by comparison with ancestors in the fossil record, we observe that a new species has evolved from the ancestral version. (Creationists call this "macro evolution" and deny that it occurs.) Conversely, during long periods of environmental stability, there may be only "routine" filtering for continued fitness, and no obvious speciation.
5. As successful species multiply and spread out over a large area, groups can become isolated, forming separate breeding populations. Over great periods of time, depending on environmental factors and the occurrence of mutations, a separate group can (if it doesn't go extinct) evolve into a new species; or it can remain relatively unchanged. The result may be a multitude of species (some living, some extinct) that can be traced to their common ancestral group. Over time, each new species can repeat this process, causing increasingly diverse species to radiate from a common origin.
Commentary: From our point of view, the filter (nature's evolution algorithm) can result in an enormous amount of waste. Uncountable legions of creatures are conceived, but never survive long enough to reproduce. What we might regard as good and useful is sometimes filtered out along with the bad. But the rule is not what we might like: "Everything nice will be preserved." Instead, it is strikingly simple -- as natural laws must be -- functioning with inexorable predictability, with no subjective judgments built in. Simply stated, the rule is this: "Only that which successfully breeds can produce players in the next round." Therefore, when the avalanche is falling, there's no soft voice that says: "Oh, this one has such nice genes, let's whisk it out of harm's way." The evolution algorithm is marvelously elegant in its operation -- but it's not what we would expect of an intelligent designer.
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Someone send a copy to Ann Coulter so she can stop making a fool out of herself.
Ann is appealing to what she believes a big part of the base.
I dont believe she actually buys it, which is dishearting. She should have just worked her way around it.
The genetec bottleneck you describe does not need to be caused by environmental change. It can result from migration or scattering of seeds to a new and isolated location.
And then Tinker Bell lived hapily ever after.
ML/NJ
True. I'm hoping my subtitle (It's far more complicated than this, but you must start somewhere) will bail me out of such oversights.
There is a guy in a class I take who loves to stand up and spew this kind of stuff. It's always mind-numbing to listen to him. With him loving his own intellect and his vocabulary and the sound of his own voice, he cares not that most of the people in the class were lost at the first sentence.
You guys should get together.
He's called "the teacher".
Someone send a copy to Ann Coulter so she can stop making a fool out of herself.
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It's gonna take a lot more than that.
Barbie says, "math is hard."
As a former student, and not a particularly good one, I can empathise. I don't criticise people for finding concepts hard. I criticise them when they take their lack of understanding and assert that all scientists for the past three hundred years are wrong.
I didn't see Jack Nicholson mentioned anywhere. ;)
Why would you want to be in a science class?
Great piece! A nice, easy-to-understand summary of how evolution works.
Beautiful, elegant explanation of a difficult concept for some people.... thank you.
bttt
Someone send a copy to Ann Coulter so she can stop making a fool out of herself.
Okay, I admit that I'm not up on all her positions - what has she said and when?
Gotta' do better than that if you want to knock down the
deus ex machina folks who want you to believe "God did it" in a New York second.
Several of the points make no sense in light of what has been found regarding the human genome, "jumping genes", and so forth.
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