Music

Don Smith don_smith at att.net
Mon Jun 17 09:33:21 PDT 2002


Steve Bougerolle wrote:
> 
> On Mon, 2002-06-17 at 00:24, Don Smith wrote:
> 
> > > 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.
> 
> Maybe I overestimate the number of fossils because I come from an area
> where they're as common as dirt :-) (that being southern Alberta).

Heck, where I live they *are* the dirt (Florida is one giant ex-coral
reef). Shells (and corals) fossilize easily because they tend to settle
on the sea bed where they are protected from the weather and can be
gently covered with fine sediment. I believe it is Alberta where there
is that excellent fossil bed from the time of the precambrian explosion.
Can't remember its name though. Some very fantastic (as in fantasy)
animals found there.

> Ok, seriously, let me be more specific about where I disagree. I am
> aware that speciation has been observed, and I don't find it at all hard
> to accept that accumulated random mutations can create new species in
> general.  However, I do find it an unsatisfying explanation of a few
> particular steps. In particular, it doesn't seem to me at all a
> satisfactory explanation of how multi-celled life can evolve from
> single-celled life.

Well, it does to me. It is a very small step from a single cell dividing
and the two resultant cells going their separate ways, to the two
remaining stuck together. There must have been some advantage to that.

> > > 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.
> 
> Well, if your point is simply that macroevolution occurs, then we can
> stop arguing because I agree with that as far as it goes.  My dispute,
> ultimately, is with too many people who leap from there to saying that
> it is a complete explanation for the shape of life as we see it, and
> then go on to (generalizing) make pronouncements that there is no
> planning or direction to the universe.  My religious interest only kicks
> in at this point, and as I said I am concerned with ethics, not
> interested in any sort of creationist debate; I don't like this view
> because I see it leading to a gross lack of respect for life and a
> dangerous overconfidence in how much we know.  In my first post way back
> when I commented on a couple signs of this; people trying to patent
> genes and blithely indulging in genetic modification for short-term
> commercial advantage.

I can't disagree with any of the above. There's no need for planning in
the theory, but that doesn't mean none occurred.

On the patent issue, I find the patenting of genes repugnant. Patents
are supposed to protect inventions not discoveries.

> > 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
> 
> Thanks for the reference.  I brushed up on the latest from talk.origins
> last night, reviewing punctuated equilibrium and genetic drift and so
> on.  All nice to read, but all just word games.

See Albert's response.

> > > 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.
> 
> You say they've been done, but I haven't seen a nice comprehensible
> summary of the results anywhere and I just went looking for one
> yesterday.

I found this, but you'll probably have to come up with the summary
yourself:

http://citeseer.nj.nec.com/context/17635/0

And for some nice equations, this:

http://www.pnl.gov/berc/kbem/vc/Theory/gi.html

My Google search of "Probability genetic mutation" came up with 42,300
hits. These were just two of them. I don't know how many had all three
words in them.

> This is another way in which evolutionary theorists make
> trouble for themselves and reinforce my impression of their bad
> attitude; when people ask simple critical questions they are too often
> dismissed as nutty creationists instead of being given simple direct
> answers.

They've heard these arguments from nutty creationists so often that if
you ask this, they assume you are one. "The probabilities are so minute
that there is no possibility of evolution happenning by accident.
Therefore, it didn't happen and the world was created in 6 days."

The real problem is that the factors that go into speciation are not all
known. And of the known ones, few of them can be measured. How do you
come up with a probability for sexual selection? Biology is not the hard
science that physics is. Trying to get creationist to understand this is
like banging your head against a brick wall.

Besides, my feeling is that the true probablity equation has a few
million terms. I don't think you will ever get the answer you are
seeking.

> I am not a creationist, except perhaps in the broadest sense of
> thinking of the entire universe as a creation; I accept large areas of
> evolutionary theory, but I am not blind to its weak spots and being
> extremely far from being a layman, I am not about to roll over and
> accept rubbish when people toss it to me as an explanation.

> Here's what would make me happy.  I did find one brief cited reference
> to a paper where somebody came up (by some means) with a figure of one
> instance of speciation per 3 million years per species.

That number is complete rubbish. Species with high generation rates (20
minutes per generation in some bacteria) can generate new species
rapidly while others take much more time. And the means used was
probably some observed rate in elephants.

> If somebody sat
> down with all the best guesses they could come up with here, and applied
> a bit of probability to them with varied parameters, to come up with an
> overall range of probabilities for, say, a badger evolving from nothing,
> that would make me happy.
> 
> Of course, there is the question of whether it would mean anything.  On
> the one hand there's thermodynamic-style reasoning; if the probability
> is so low that it would never happen in a billion times the most
> generous age estimate of the universe, that would tell me conclusively
> that biologists are missing something.  If the figure is significantly
> lower, then we have to consider the anthropomorphic principle and the
> result is unclear, but it would still be interesting just as a measure
> of how much we don't know.

The unknown is infinitely large, IMHO. Therefore, what we know is a
close approximation of zero.

> In any case, it would be a lot more satisfying than word answers to a
> mathematical problem.
> 
> > 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.
> 
> The straightforward answer to this is that as you go farther back in
> time you would expect the record to be more skimpy because more would
> have been destroyed in the longer period since being laid down.

No, I'm not talking about the number of fossils found, I'm talking about
the number of different species found. In the bottom layer, right after
the large die off of the dinosaurs. They have found many examples of
small shrew-like mammals. They have found not one elephant fossil from
that time (or deer or cat or dog or anything more advanced than many
different kinds of small shrew-like mammals). But now my argument comes
back to haunt me, "Absence of evidience..." Well, before I was talking
about a single missing species (the common ancestor of man and
chimpanzee), now I am talking about thousands/millions of missing
species. True, we could have just not found them yet.

Don
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