Jamie, John, Mark, and all,

First, a very Merry Christmas to you all!

I can feel sympathy for John and Mark. On the other hand, I am a
biochemist.....

I first read Charles Darwin's "Origin of Species" when I was in high school
(only a couple years after John finished high school, I suspect). I was
mentally prepared for it when I started to read it, and it made deep and
lasting impression in my thinking. As we now realize, evolution isn't a
hypothesis, it is the theoretical foundation of our understanding of all
modern biology. Without it, biology would not be a coherent science.

At the heart of it all is the genetic system of living
organisms. Evolutionary descent is all about changes in genetics. Those
"genetics" are in fact the copying, transmission, and changes in DNA, and
their subsequent expression in the living organisms. The modern molecular
geneticist has mathematical tools to help him or her estimate the
relatedness of the DNAs of whole groups of organisms. The overt physical
structures of organisms are handy tools for identifying them to Genus,
species, and subspecies. But they are rough approximations. The DNAs are
in fact the written records of the relationships between organisms.

Structural or anatomical schemes for classifying organisms were a great
start for biology, but they go clear back to Carl Linnaeus in the 18th
century. So while we may lament the fading of some of the old, familiar,
tools of our trade in horticulture and botany, the brave new world of
molecular genetics is in the long run going to be the story -- the truer
story -- of life on our planet. I think the old structural keys to
identification will still be useful, but as Jamie said, we will need
cross-references to connect them to the new, molecular classifications and
taxonomy.

In the new, cladistic approach to classification, there are ambiguities,
just as there were in the old. Whether Scilla should be split into two or
into twenty other genera is always going to be somewhat a matter of
opinion, rather than fact. The facts never have and still do not fall
neatly into categories of Family, Genus, and species.

What is important, and the revisions that will persist in the long run, are
those that remove less-related groups from our older genera. Moving some
Scilla to Muscari would imply that Scilla as it used to be was not made up
of plant species all of which were more closely related genetically to each
other than any of them was to any species outside Scilla.

Alan Meerow has seen the same things with the Rain Lilies, where our older
existing groups of Zephyranthes and Habranthus do not obey the rule of
nearest relatives. There are apparently three groups, not two, and their
members are scattered between both thiese traditional genera. Length of
the stamens turns out to be a superficial trait, not a fundamental one.

I see a bright future in the next few decades for those writers who can
rationally and clearly connect the conclusions of the new biology to the
traditional approach. Your next book, John?

Best to all,
Jim Shields
hardcore biochemist

At 07:49 PM 12/23/2003 +0100, Jamie wrote:

*************************************************
Jim Shields USDA Zone 5 Shields Gardens, Ltd.
P.O. Box 92 WWW: http://www.shieldsgardens.com/
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344 or toll-free 1-866-449-3344 in USA
Member of INTERNATIONAL CLIVIA CO-OP

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