I finally got around to the Developmental Biology (February 1, 1996;
Volume 173, Number 2) articles that Denis Lamoureux had recommended to us.
(I've included his original post below since it was so long ago-- at least
in reflector time.)
The first article "Resynthesizing Evolutionary and Developmental Biology"
(pp. 357-372) by Scott Gilbert, John Optiz, and Rudy Raff is MUST reading
for any Christian critic of evolutionary theory. The new synthesis that is
being proposed addresses most, if not all, the anti-evolutionary arguments
that many critics raise. (No dicussion of origin of life issues though.) I
had heard Gilbert lecture on some of this material at the "evo-devo"
meeting at Indiana University in the fall of 1994. I am delighted to see
this piece in print. I had written in my review in 1992 of Phillip
Johnson's *Darwin on Trial* the following:
"In the 1991 edition of an upper-level undergraduate textbook in
developmental biology the last chapter is devoted to the evolutionary
implications of some of these recent findings. The author even suggests
that there is a new synthesis on the horizon bringing together
neo-Darwinism, molecular biology, developmental biology, and paleontology
(punctuated equilibrium)."
[For anyone who cares, my review is now available on
the Web at
http://mcgraytx.calvin.edu/gray/evolution_trial/dotreview.html]
Of course, I can't claim this new insight for myself. The 1991 textbook
was Gilbert's own *Developmental Biology* (3rd edition, Sinauer,
Sunderland, MA)--now out in the 4th edition (1994) but with the chapter on
development and evolution unchanged.
The interesting thing about this is that what Scott Gilbert wrote in 1991
given the scanty results that he had at hand then has exploded into a most
amazing confluence of results from all these disparate disciplines.
Here's the abstract to the Gilbert et al. article:
"A new and more robust evolutionary synthesis is emerging that attempts to
explain macroevolution as well as microevolutionary events. This new
synthesis emphasizes three morphological areas of biology that had been
marginalized by the Modern Synthesis of genetics and evolution:
embryology, macroevolution, and homology. The foundations for this new
synthesis have been provide by new findings from developmental genetics and
from the reinterpretation of the fossil record. In this nascent synthesis,
macroevolutionary questions are not seen as being soluble by population
genetics, and the developmental actions of genes involved with growth and
cell specification are seen as being critical for the formation of higher
taxa. In addition to discovering the remarkable homologies of homeobox
genes and their domains of expression, developmental genetics has recently
proposed homologies of process that supplement the older homologies of
structure. Homologous developmental pathways, such as those involving the
*wnt* genes, are seen in numberous embryonic processes, and they are seen
occurring in discrete regions, the morphogenetic fields. These fields
(which exemplify the modular nature of developing embryos) are proposed to
mediate between genotype and phenotype. Just as the cell (and not its
genome) functions as the unit of organic structure and function, so the the
morphogenetic field (and not the genes or the cells) is seen as a major
unit of ontogeny whose changes bring about changes in evolution."
Gilbert et al. refer to three rediscoveries: macroevolution (i.e. the
interpretation of the fossil record promoted by advocates of punctuated
equilibrium--Gould, Eldredge, Stanley, Vrba); homology--that extends to
developmental programs as exemplified by recent molecular developmental
homologies found between arthropod and vertebrate eyes and limbs; and
morphogenetic fields, a theoretical framework used in late 19th century and
early 20th century developmental biology, but largely occluded by a gene
centered approach to development--now a biochemical basis for morphogenetic
fields has been discovered.
I'd like to add two additional ideas to the mix. 1) The notion of
morphological laws as recently discussed by Brian Goodwin in his *How the
Leopard Changed Its Spots* and 2) Principles of non-linear dynamics,
complex systems, and self-organization as advocated, say, by folks at the
Santa Fe Institute. [For some reason Gilbert doesn't discuss these two
additional ideas, although Goodwin's book is cited, as well as another
article of his in the *Journal of Theoretical Biology*. Goodwin has
co-authored articles with Stuart Kauffman of the Santa Fe Institute, so
even these last two ideas can be linked together.]
In my opinion you have a powerful alternative to the neo-Darwinian
synthesis for a robust and broadly applicable evolutionary theory
(although, it should be pointed out that much of Darwinism is subsumed in
this new synthesis). Not only that, but these new ideas seem to have a
much greater sensitivity to biological phenomena in their own right, i.e.
organisms are more than just their genes or their biochemical components,
but unique wholes with novel emergent properties that must be studied in
their own right and at their own level.
TG
Denis wrote:
>Just a few papers I think would be well worth your while spending some
>time on. Last year in February I was interacting with Dr.
>Plantinga on this reflector and challenging him with regard to his
>skepticism toward evolution. The thrust of my argument rested on some
>of the latest work in the new subdiscipline of developmental evolutionary
>biology. For too many years now biology has functioned with what I call a
>"one-gene-one-trait" mentality, and employing this paradigm certainly
>gives SOME just cause for a suspicion toward evolution (which, yes, to a
>certain extent, justifies the criticisms Dr. Johnson et. al.) However, with
>the recent explosion of biolmolecular data, in particular in developmental
>biology, there is a new and more robust synthesis of evolution emerging.
>In a word, there is a paradigm shift going on and the more I come to
>appreciate it and view biology through these categories the easier it
>seems to me that the Lord created through an evolutionary process. To
>use Dr. Van Till's term, life and its origin looks a lot to me like an
>"evolutionary creation."
>
>Please consider three papers in one of the world's best biology journals,
>DEVELOPMENTAL BIOLOGY (Feb 1996):
>
>1) Gilbert, S.F., et. al., Resynthesizing Evolutionary and Developmental
>Biology. Pp. 357-357.
>
>2) Valentine, J.W., et. al., Developmental Evolution of Metazoan
>Bodyplans: The Fossil Evidence. Pp. 373-381.
>
>3) Holland, P.W.H., et. al., Hox Genes and Chordate Evolution. Pp. 382-395.
>
>An interesting caveat for some of you aware of my current doctoral work:
>I am constructing a dentition development theory that I have
>recently termed the "Odontogenic Field Theory." This model fits
>extremely well with what Gilbert et. al. have stated in their paper
>regarding "the rediscovery of the morphogenetic field." The plasticity
>afforded to a biological system such as the dentition within this context is
>extensive and could easily account for dramatic and quick morphological
>change due to a very limited genetic variation in a genetic series (eg,
>HOX 7 or 8 in the case of teeth) that supports a morphogenic field.
______________________________________________________________
Terry M. Gray, Ph.D. Department of Chemistry and Biochemistry
Calvin College 3201 Burton SE Grand Rapids, MI 49546
Phone: (616) 957-7187 FAX: (616) 957-6501
mailto:grayt@calvin.edu http://www.calvin.edu/~grayt/