|
|
Creationists and Change
Andrew Petto (AJPETTO@MACC.WISC.EDU)
Mon, 11 Mar 1996 07:51:00 CDT
I know Vance has experience with Creationists in Florida, but I think he is over
generalizing that their theology/cosmology allows no change. Their favorite
example is the peppered moth, too, because they admit that organisms are endowed
with an ability to adapt to their environments, but they point to the recovery
of the light-colored morph as proof that evolution has not occurred -- just a
temporary change in gene frequencies. The problem for us is to convince the
general public and our students that these changes *do* lead to the kinds of
morphological change -- emergence of new species -- that we are convinced that
it *can*. The creationists have us on many examples of this -- dog, pigeon,
farm animal breeding; we have changed genes around, sure, but have we made new
species?
THe connection between genetic change and new species is the crux of the matter
for this argument. Creationists don't deny genetic change occurs, only that it
necessarily adds up to evolution.
Now, specifically to Vance's comments:
Yes, it can be said that evolution has taken place in the last 8
decades as a result of the changes in allele frequencies.
Evolution is change, not progress, just change. Changing allele
frequencies have led to differences between you and your
ancestors.
I never argued for *progress* of any sort; to paraphrase (comments attributed to
) Freud, "Sometimes genetic variation is only variation." What evidence do we
have that this variation is (not could be or could lead to, but *is*) evolution,
except that some of us choose to define it that way (and because we kow that the
other changees that are associated with evolution require that genes be changed)?
Vance wrote further:
I wish there was no association between "new taxa" and "higher
taxa," new taxa is enough. Any specific pattern of genetic
change is evolutionary change. Why is this not enough?
Evolution does not have direction, nor hierarchy.
The new taxa/higher taxa thing is not a very important distinction All I was
referring to was speciation. I would argue that evolution requires speciation
-- not progress, not hierarchy, not direction. But these speciation events
bring into being new biological (and behavioral) structures and functions that
form a foundation for new ways of life -- thus, "higher" or perhaps I should say
"more inclusive" taxa, taxa that include variations on a major organizational
theme.
So, my argument is that genetic variation is only variation. It is a necessary,
but not sufficient condition to demonstrate evolution. By defining evolution
only in terms of genetic variation, we come to accept low-level, local,
short-term variations that may or may not contribute to an evolutionary change
as the change itself.
Anj
Andrew J. Petto, Editor, National Center for Science Ed.
c/o Dept. of Anthropology, University of Wisconsin
1180 Observatory Drive, MADISON WI 53706-1393 ajpetto@macc.wisc.edu
voice: 608/259-2926; fax:608/258-2415
NCSE email: ajp3265@madison.tec.wi.us
|