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Hi again,
Vacation, recovery-from-vacation, and dealing-with-things-which-
accumulated-while-on-vacation prevented me from responding sooner, but
here I am.
Steve offered this proposal:
> Gould once wrote in a famous paper:
> "I do not doubt the supreme importance of preadaptation, but the
> other alternative, treated with caution, reluctance, disdain or even
> fear by the modern synthesis, now deserves a rehearing in the light
> of renewed interest in development: perhaps, in many cases, the
> intermediates never existed. I do not refer to the saltational
> origin of entire new designs, complete in all their complex and
> integrated features-a fantasy that would be totally anti-Darwinian in
> denying any creativity to selection and relegating it to the role of
> eliminating old models. Instead, I envisage a potential saltational
> origin for the essential features of key adaptations. Why may we not
> imagine that gill arch bones of an ancestral agnathan moved for- ward
> in one step to surround the mouth and form proto-jaws? Such a change
> would scarcely establish the Bauplan of the gnathostomes. So much
> more must be altered in the reconstruction of agnathan design-the
> building of a true shoulder girdle with bony, paired appendages, to
> say the least. But the discontinuous origin of a proto-jaw might set
> up new regimes of development and selection that would quickly lead
> to other, coordinated modifications." (Gould S.J., "Is a new and
> general theory of evolution emerging?", Paleobiology, vol. 6(1),
> January 1980, p127)
> This is my proposal of what happened - God at strategic points
> supernaturally injected a new design into life's history (eg. a
> change to the genetic code specifying a gill-arch became a jaw).
> Thereafter, natural (ie. "evolutionary") processes would take that
> change until the next major step (eg. a foot from a fin). This is
> fully in accord with the scientific facts and also with the account
> of God's progressive acts of creation in Genesis 1.
>
> Comments?
I like it. It's reasonably specific and, I agree, it is
"fully in accord with the scientific facts and also with the account
of God's progressive acts of creation in Genesis 1."
I agree that there probably are "strategic points" in biological history.
Most of the microevolution we see today, and the long periods of relative
stasis in the fossil record, suggest that MOST of the time, genomic
changes in a species are minor adjustments to a changing environment.
Examples of rapid speciation (e.g. when a bird or insects arrives at an
isolated island) are more interesting and dramatic, but still would be
called "microevolution." As we learn more molecular biology,
developmental biology, physiology, and environmental science, we might
eventually get pretty good at "predicting" this sort of microevolution.
But then there are those dramatic, very rapid appearances of significant
morphological changes in the fossil record. Developmental and molecular
biology suggest that "sudden" morphological changes are due to changes in
one or more "control genes" for developement. Once such a "macro" change
happens, microevolution can "do its thing." But the type and the timing
of such occurences seems far less predictable, in some cases perhaps
being completely unpredictable.
Like Steve, I think God was completely in control of what happened at
those "strategic points."
If I were to slightly re-word Steve's proposal, above, it would be
agreeable not only to nearly all progressive creationists, but also to
nearly all evolutionary creationists/theistic evolutionists. How about
this:
At strategic points in biological history, God brought about new
designs (eg. a change to the genetic code specifying a gill-arch
became a jaw). Thereafter, ordinary (ie. "microevolutionary")
processes (under God's providential control) would operate on
that design until the next major step (eg. a foot from a fin).
This is fully in accord with the scientific facts and also with
the account of God's progressive acts of creation in Genesis 1.
This leaves open the question of whether or not certain "strategic points"
were necessarily "supernatural;" it also suggests a line of research! We
look in the fossil record for points of rapid morphological change, and
then study the genes which determine that change in modern species.
(Note: there are already a few groups doing this kind of research. I
recall reading a _Nature_ article about a year ago on, I believe, the
tetrapod foot.) Here comes the difficult part, which is still beyond our
scientific abilities: we try to determine if this morphological change
could have happened with a single mutation (or perhaps a very small number
of changes with viable intermediates), or if this change would have
required a large number of precise mutations without viable intermediates.
(Personally, I'm hopeful that we WILL, eventually, have the ability to
make that sort of determination.) In the former case, we would be
inclined to say that God brought about that new design through "ordinary"
(albeit strategic) providential control (though logically, we couldn't
exclude a "supernatural intervention"); in the latter case, we would have
a strong case for supernatural intervention.
In the mean time, PC's like Steve are willing to go out on a limb and say
that the scientific and theological data suggests that there were a number
of "supernatural interventions." (Thus, PC's will no doubt prefer Steve's
proposal's wording over mine.) That's reasonable, but EC's like me are
willing to go out on a limb and say that the scientific and theological
data we have so far suggests "providential control" at those "strategic
points."
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"There's nothing more exciting than science. You get |
all the fun of sitting still, being quiet, writing | Loren Haarsma
down numbers, paying attention. Science has it all!" | lhaarsma@opal.tufts.edu
--Principal Skinner (_The_Simpsons_) |