If I remember back that far, he matters in this discussion because we
were trying to establish what evolutionists thought about Lloyd's points
M-N (I can't remember the numbers :-)). We seem to have moved away from
that discussion, however...
> > Gene flow is not the same thing as horizontal transfer. Horizontal
> > transfer refers to a mutational process that moves genetic material
> > across taxa. Gene flow is the within-species but inter-populational
> > exchange of genetic material. Horizontal transfer is, AFAIK, very
> > rare, being accomplished by such mechanisms as viral transcription.
> > Gene flow is exceedingly common, and is seen as a nearly completely
> > effective obstacle to speciational processes.
My error. I was thinking of horizontal transfer, and mistakenly got
'gene flow' caught in the net. I'd only add that I've heard some people
opine that transfer is more common than we think, but I don't know what
the current state of play is on that question...
[...]
> I don't agree. If one holds to the 6000 year view (or any form of
> young-earthism) -- a view clearly refuted by easily-observable geological
> and palentological evidence -- then one cannot even begin to discuss
> evolution because one cannot admit the minimum required for discussion: a
Perhaps not 'evolution' the way you mean, but this is exactly (or nearly
exactly) the discussion which took place 150 years ago--Darwin & cronies
argued mainly the first two or three points in the Mayr description I posted--
evolution as such and common descent and non-fixity of species. There
was a 'balance of nature' feeling which held very strongly that God's
creation, as perfect, couldn't lose species to extinction--they all still
have to be around somewhere. (You can still find vestiges of this idea
around today in abortive dinosaur hunts in Africa.) These sorts of
arguments are evolutionary (at least according to Mayr), and they can be
carried out with young-earth creationists (indeed, they're the only sort
which can be, I'd guess, since that is the bottom line point of disagreement).
The early Darwinists used gradualistic selection as an answer to the
conceptual question, "Oh, yeah? Well how is this 'common descent' supposed
to work?" By presenting a plausible mechanism, Darwin had a response to
this powerful conceptual objection to his theory of common descent--he had
a mechanism to propose which could explain how such a thing might come to
pass.
[...]
> But this gets us only to my #2 -- to the statement that change
> occurs in biological populations. Any observant person will admit the
> truth of that claim.
But many observant folks also note that that change which we see is
often contained within certain limits--the idea of 'species' seems in
most cases to be a natural and powerful division. This warrants an
explanation (which evolutionary theory can give), but I think it is
still grounds for a good question.
[...]
-Greg