Re: Evolution's real problems

"Marc" <mbuhler@xxxxxxxxxxxxxxxx> writes:

> Mark Isaak wrote:
> > Logos just made up a list of what he thinks are problems for evolution
> > to deal with. Here, as a holiday present to him and other
> > creationists, is a list of real problems dealing with evolution.
> >
> > Note that "problem," as I use it here, means an unanswered question,
> > not a defect. I am aware, of course, that creationists may be
> > dishonest enough to interpret my list in the latter sense. As I said,
> > Happy Holidays!
> >
> > 1. How did the first life originate?
> > 2. What factors are most important in causing and maintaining sex?
> > 3. What factors are most important in causing speciation?
> > 4. What macroevolutionary mechanisms, if any, are not equally
> > microevolutionary mechanisms?
> > 5. What, exactly, are the evolutionary relationships of, well, all
> > organisms?
> > 6. What caused the Permian extinction?
> > 7. How and when did human language evolve?
>
>
>
> Well, I hate to take something away from IDiots, Evo
> disbelievers and fundies, but point #7 does have an
> answer in terms of a specific human mutation leading
> to the ability to speak. I cited this (abstract copied below)
> in the Human Evolution Today thread a couple of weeks
> ago.... and of course, it was mentioned in a couple of
> posts about two years ago as John Wilkins would be
> likely to recall. (This was just after my talk at the 19th
> Congress of Genetics, and Molly Przeworski spoke
> just before I did....)

I'd phrase it a little more cautiously: FOXP2 may have been
under selection in humans, and that selection may have had something
to do with language. The genetic evidence is a little weak and
not entirely consistent. The strongest evidence is the nonsynonymous
substitutions (two, if I remember correctly) in the human lineage, in
an otherwise highly conserved gene. That may indicate positive
selection, but may also indicate relaxed selection; two is just not a
large number, statistically.

The evidence from human genetic variation data was less persuasive.
The strongest indication was from an excess of high-frequency derived
alleles, but without a clear reduction in overall diversity. That's
odd, since the diversity signal lasts several times longer than the
derived allele signal, and the proposed time of the sweep was at the
extreme end of the sensitivity of the latter test.

The functional evidence is that mutations in FOXP2 cause language
defects in modern humans. That doesn't really tell you whether the
earlier substitutions in the gene caused the development of language,
however. Damaging a protein can cause all sorts of effect.

This is not to say that FOXP2 wasn't involved in the development of
language, but just to point out that conclusions about these issues is
difficult, and the evidence is likely to be fragmentary.

--
Steve Schaffner sfs@xxxxxxxxxxxxx
Immediate assurance is an excellent sign of probable lack of
insight into the topic. Josiah Royce

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