BOOKS
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to her vast reservoir of biodiversity, although each extinction left dramatic
changes in the relative abundances of different kinds of creatures in its
wake. But according to him, the seventh, anthropogenic mass extinction
is so brutal and its impoverishment of biodiversity so severe that with
each passing moment the environment is destablized more and more. It is
simply reckless, says Wilson, to suppose that biodiversity can be dimin–
ished indefinitely without threatening humanity itself. Who are these
reckless people? Is there anyone who supposes that humanity would not
be threatened when the indefinite diminution of biodiversity has reached
the point at which
Homo sapierls
remains the lone voyager on Spaceship
Earth?
The bulk of
The Diversity of Life
is dedicated
to
arguing that the call
for mankind to make the preservation of biodiversity its paramount telos
is actually grounded in more than apocalyptic prophecy and environmen–
tal platitudes. One part of the brief is descriptive. It presents a synchronic
survey of a colorful palette of extant creatures, great and small, and their
intricately interwoven, complex ecosystems, as well as a diachronic record
of the evolutionary development of the species. According to Wilson,
biodiversity was ever-waxing until the genus
Homo
"walked upright onto
the stage, bearing Promethean fire - self awareness and knowledge taken
from the gods - and everything changed."
The second part of the brief is analytical in intent, addressed to ques–
tions of the evolutionary mechanisms responsible for, and the practical
benefits derivable from, biodiversity. Here Wilson's descriptive skills do
not suffice for presenting the authoritative treatment readers have the
right to expect from an expert. He does acknowledge frankly his
awareness of the enormous complexities and conceptual quicksands of the
subject, yet he does not deal with them in a logically coherent mode or
with enough sophistication.
By insisting on identifying the "biological species" (i.e., "a population
whose members are able to interbreed freely under natural conditions") as
the "fundamental natural unit" in terms of which the world of organisms
has to be fathomed, Wilson entangles himself (and his readers) in the
evolutionary donnybrooks of yesteryear. For if there is one overarching
lesson that latter-day molecular biology has provided for the students of
systematics and evolution, it is that the fundamental natural unit at the or–
ganismallevel is the
gerlome,
the set of homologous DNA nucleotide base
sequences with which organisms of common descent are endowed.
(Throughout his book, Wilson incorrectly alludes to such sequences as
"genetic codes," a term by which the molecular biologists who made it
up mean the symbolic relation between a particular nucleotide base triplet
and the protein amino acid it represents.)
