Music

Don Smith don_smith at att.net
Sun Jun 16 09:24:56 PDT 2002


Steve Bougerolle wrote:
> 
> On Sun, 2002-06-16 at 01:51, Don Smith wrote:
> 
> > Mutations occur all the time.
> Yes. This is beside the point, however.

No, it is not. You said

"It still does nothing to explain HOW."

And to me mutation is the how. Millions of small changes over a very
long time add up to large changes.

> > Very, very rarely a mutation occurs that is actually beneficial, ...
> Oh, don't be patronizing. 

Sorry, I wasn't trying to be. Again, referring to the quote above, I was
just trying to show you that it does indeed explain how.

> The idea of natural selection isn't at all
> hard to grasp.  That doesn't, however, mean it works. If natural
> selection of mutants generates new life forms, then either there should
> be a lot more intermediate forms than we have seen, or else successive
> mutations need to occur in a short period of time. 

This argument is used all the time. People who use this argument don't
seem to get it. A very very small number of individuals fossilize. The
vast majority of those fossils are still buried under thousands of feet
of overlayment. Most fossils that become exposed due to erosion are
themselves eroded away or are moved out of context and become less
useful. We are a very long way from finding every fossil ever formed.

> The absence of
> intermediate forms can be explained partly by the difficulty of finding
> fossils, but that isn't really convincing

Well then we just disagree because it is convincing enough for me.

> and it does nothing to address
> even bigger problems like the beginnings of single-celled life.

Now, here I agree there is a problem. But then it is not really with
evolution because evolution theory presupposes ancestors. The problem is
how did life first form. The thermal vent ecosystems have shown us some
archaic simple bacteria that thrive in extremely harsh environments
(coming from one direction) and other experiments have shown ways that
complex organic chemicals *may* have been formed (coming from the other
direction). But there is a *huge* gap between these two.

> There are other selection mechanisms.  IIRC, Darwin came to favour
> sexual selection.  That's unconvincing, too, but in recent decades
> there've been a lot of more complex and (heh heh) evolved arguments
> about natural selection that I'm quite open to hearing about.

Hmm. Natural selection is a term used to differential naturally occuring
selection pressures from human selection of the most desirable traits in
domesticated species. Predation, sexual preference, enviromental
changes, etc. all are natural forms of selecting for the most fit
individuals. Darwin did not prefer sexual selection over natural
selection, he came to see it as a very important selection mechanism
under natural selection.

There is a better explantion here:

http://www.sprl.umich.edu/GCL/paper_to_html/selection.html

> 
> It might be that someone can show a satisfactory selection mechanism.
> However, I'm not going to be impressed by simple word arguments.  Darwin
> could get away with that but in this computing age I expect to see some
> probabilistic analysis.

They've been done. Another argument creationists use to attack evolution
theory. They keep ignoring the immense amount of time and large
populations involved in evolution theory.

> This is just the same amount of respect and
> acceptance I give to some ideas in my own field, say cosmology.  The
> subject is interesting and for sure there is value in it, but that
> doesn't obligate us to accept everything a cosmologist pronounces to be
> true.
> 
> > I don't think you understand. Evolution *is* the mechanism the explains
> > how these changes occur.
> On the contrary, I think I understand it pretty well.  "Evolution" is a
> catch-all term for a phenomenon involving lot of different ideas about
> mutation and selection.

No, it is not. It is a well defined theory. See link given above.

> Invoking the term might invoke mystical
> religious-like awe in some people, but not me.  I like to hear the
> details.
> 
> Evolution also tends to be confused with adaptation (as in the previous
> quoted famous example of the black & white moths in the UK).  No
> reasonable person doubts that adaptation exists.  This is not at all an
> explanation of how deer can evolve from protozoa.

Yes it is a part of it.

> > There is no problem with the overall theory of evolution, i.e., natural
> > selection of random mutations. I guess by problem, you mean it is still
> > a theory. It will *always* be a theory because there is no way to ever
> > prove it (without a time machine).

> Of course there is a problem.  If there were no problem biologists
> wouldn't have spent so much time thinking up alternative selection
> mechanisms.  Simple natural selection has been out of favour for over a
> hundred years.  Update yourself, Don...

Already answered. Um, I studied biology in college (admittedly a long
time ago). The only new things I've heard about is the punctuated
equilibrium theory which says that yes indeed there are periods of large
changes interspersed with long periods of relative stability in species.

> 
> > 65 million years ago there were only a few species of small rodent-like
> > mammals.
> Now see, you've just done the one thing in all this that I REALLY object
> to.  You are stating a presumption as if it were truth.  In this case
> it's doubly objectionable because you're also contradicting yourself;
> you just said you can't prove things about the long-ago past.

Okay, I accept the 65 million year time because I understand how they
arrived at that figure. But I'm willing to say it can be any number you
like because it is not a fact. However, finding only a few species of
rodent-like mammals in the lowest strata, is a fact. Increasingly higher
strata contain increasingly more diverse species of mammals, is a fact.
Higher strata must have been laid down after the lower strata, hmm, not
a fact but an inference. Can you reasonably explain the lower strata
being newer? And mammals are just one example out of hundreds of
classifications.

Don
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