experiments and evolution

LHAARSMA@OPAL.TUFTS.EDU
Tue, 18 Jul 1995 16:07:17 -0500 (EST)

There have been several posts lately following this pattern: Glenn Morton
quotes an experiment in which a "control" gene was altered in an organism,
or a small surgical procedure performed on a developing embryo, which
resulted in a large morphological change in the adult organism ("B") IN
THE DIRECTION OF the putative ancestral form "A." Glenn offers this as
evidence in support of evolutionary development from A to B. Stephen Jones
and Jim Bill criticized this by saying (1) Since the alterations were
performed by an intelligent agent, this is more like evidence for
Progressive Creation; and (2) What about all the OTHER mutations required
to transform creature A into creature B?

Maybe we can agree on some common points. Let me suggest:

1) The experiments Glenn cites are evidence for common ancestry, or at
least the strong appearance of common ancestry. (This fits into either
theistic evolution or progressive creation. The experiments themselves
cannot tell whether the new developmental genes in creature B arose from a
sequence of "natural" mutations, or _ex_nihilo_ creation of a new gene
SIMILAR to A's, or anything in between.)

2) The fact that the experiments were performed by an intelligent agent is
a moot point. Both T.E. and P.C.-with-common-ancestry predict the same
result from the experiment, so the experiment doesn't preferentially
support one or the other in that respect.

3) In order to "prove" evolutionary development from A to B (insofar as
any such hypothesis can be "proved"), we would have to find a mutational
pathway through viable genomic phase space which was sufficiently "short"
(to allow for a realistic rate of mutations and substitution into the
population). To _disprove_ evolutionary development, we would have to
show that there is NO "sufficiently short or viable" pathway. The
experiments which Glenn cites are just a begining, sort of a signpost on
the path. They show that a small part of the pathway is shorter than we
might otherwise have expected, but a lot more work will have to be done to
settle the issue.

Is that reasonable, or am I just starting a new argument? :-)

--------------------------------------------------------------------------------
I try to make everyone's day a little more surreal. | Loren Haarsma
--Calvin (_Calvin_and_Hobbes_) | lhaarsma@opal.tufts.edu

(p.s. No more posts from me for two weeks. Vacation!!!)