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Theories of Evolution

I've seen things you people wouldn't believe... gwyckoff at ellis.uchicago.edu
Wed Sep 7 23:28:56 EST 1994

	If the alleged engineer who posted the response that evolution violates
thermodynamic laws would like, perhaps they could try to look at evolution
as taking place at the level of an entire ecosystem, as opposed to at an
organismal level.  Though evolution does take place at the level of an organismin one sense, the origin of life, which I believe what had the engineer in 
question in such a state, most likely took place in a chemical soup.  In which case, an increase in relative "order" in one part of the system would likely
occur with an increase in entropy in another portion of the system.
	Evolution, at the level which it is most commonly applied, does not
address the very early part of the history of life.  It really only applies
since DNA (or at least, a self replicative molecule) has existed.  In which
case, we are really speaking of Molecular Evolution. (caps for emphasis.)
Molecular evolution involves the random replacement of base pairs in DNA,
and therefore a sort of reshuffling of genetic material due to mutation.
This violates no physical laws.  In fact, one could make an arguement that
entropy in a system actually increases if the genome size increases, but
that is not really relevant to the topic.

	I believe that the initial poster wanted to know about the different
theories of evolution.  In reality, most of the historical theories about
how evolution occured have been discredited.  LaMarck believed that organisms
inherited those characteristics that their parents derived during their life.
The classic experiment that disproved this was that if you take two rats, a male and a female, and cut off their tales and subsequently breed them, they
do not have progeny with no tails (as LaMarck would have predicted.) (NOTE:
I don't really recall wether it's Lamarck or LaMarck.) This proved to be
true even after several HUNDRED generations.
	Darwin believed that Natural selection acted upon variation which
was already present in a population in order to produce different characteristics after many generation of selection for a given trait. The idea here is that
the variation is inherint in the population.  With the rediscovery of Mendel's
work with pea plants, genes were seen as the units which defined a trait, and
alleles are the variations within that trait.  It's a little more complicated
than this, but it would take much longer than I have. Anyway, the so-called
Modern Synthesis is the use of the method of heritable variation discovered by
Mendel to make sense of the observations of Darwin.  This is called selectionism.
	There are some other ideas, but I can't go through them all here.
For references, please see the textbook
	Evolutionary Biology by Douglas J. Futuyma, 2nd edition, Sinauer Associates Publishers, Massachusetts

	or for a historical perspective, see any of the works by
	Dr. William Provine, Cornell University

	That's for a start.  There's a wealth of information out there.

	And please note that this channel is for serious discussion.  Someone
actually asked a question here.  Just posting that Evolution violates a 
thermodynamic principle with a refernce to a work that explains the principle
but not how evolution violates it just dosen't cut it.  It's just flame bait.
So keep your mind open and talk, or just lurk, but if you can't discuss or have
nothing worthwhile to contribute, buy a Nintendo and leave the rest of us alone.



		These are my own views or opinions unless someone
else has been cited.

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