Bell said, "The most remarkable feature of Kirk's book, however, is that it
transcends conventional genetic analysis to also include evolutionary and
ecological analyses. When we speak about mechanism in the context of
development, we usually mean something strictly physiological that explains
how genes are expressed and how their products react. Only rarely do we
consider a quite different category of mechanism, one involving the variation
and selection of developmental pathways. Even more rarely is a single author
able to present both categories in the same volume" (p. 248).
I find this multi-level analysis refreshing. Too often, as Bell said, the
analysis is uni-dimentional, either developmental or evolutionary. It is my
position that development and evolution are the yin and yang of change over
geologic time. In general, I see development, as operating not only in
embryogenesis, but also as a long-term process in phyletic morphogenesis. It
is primary, because it is teleological, internally directed, hierarchically
organized, and thus is the principle that provides differentiation and
organization in organic life. I see natural selection as opportunistic,
providing diversity and adaptibility to the basic developing phyletic lineage.
What I find remarkable about the next-to-the-last sentence in Bell's review
is that (1) the mechanism is straight forward Darwinian natural selection, and
(2) development precedes natural selection. Development is primary; variation
and selection of developmental pathways are secondary.
I have ordered Kirk's book ($85!) and will check out whether Bell's assessment
of Kirk's position is on target and whether my interpretation of Bell is
correct.
My thinking is in process.
Bob