The Diversity of Life

Posted: 27 March 2001

Author: Edward 0. Wilson
The Belnap Press of Harvard University
Cambridge MA, 1992, $29.95

How can a human species bent on habitat destruction built up over millions of years control its appetites and penchant for rapid extinction of other species? Edward Wilson, one of the world's leading entomologists and naturalists, has written a beautifully illustrated and designed book to demonstrate that our species and other life forms can mutually and productively share the same planet.

Chock-full of thoughtful examples, practical suggestions, philosophic insights and stunning colour photographs, drawings and charts, and a helpful set of bibliographical footnotes and glossary, Wilson has produced a tour de force.Darylne A. MurawskiThe first two-thirds of the book succinctly surveys a vast scientific literature concerning the nature of past extinctions of life, the creation of new species, the forces of evolution and adaptive radiation, life in the forest canopy and beneath the oceans, and the importance of ecosystems. The writing is vivid and personal, the analysis of scientific controversies such as the meteorite impact theory on dinosaurs is scrupulously fair, aided by lucid footnotes and admission of lack of knowledge. Thus the total known number of species is estimated at 1.4 million; the total number of species on the planet at somewhere between 10 and 100 million.

The last third of this vital book addresses the human impact. It calculates the number of species "doomed each year is 27,000. Each day it is 74, and each hour 3". Species extinctions which took place over a period of one million years now take place in a human lifetime or less. Nor can laboratory synthesis or breeding in botanical gardens, seed banks or zoos rescue more than a handful of species condemned to extinction. The case for preserving maximum biodiversity is made on firmly utilitarian grounds. "Biodiversity is our most valuable but least appreciated resource." Wild species contribute to hybrid, resistant food crops, to critical pharmaceuticals and to hosts of other benefits to humans. Yet our knowledge of biodiversity barely scratches the surface and each extinct species represents a permanent loss of knowledge and value.

Since half the known species exist in tropical rainforests, 6 per cent of the planet's surface, the critical test is whether our species and this treasure-house of biodiversity can co-exist. Wilson is optimistic, arguing with examples that sustainable biological wealth can out-yield commercial logging and slash-and-burn cultivation. The briefly presented examples, from ranching iguanas and Amazon river turtles to strip logging to harvesting wild plants, are intriguing, albeit still in pilot stages. The conclusion is to reject cost-benefit analysis which undervalues benefits from rare and endangered species in favour of "the safe minimum standard" which treats each as "an irreplaceable resource for humanity".

Preserving species includes for Wilson "population management". He advocates each country choosing its own optiinal population to be implemented by encouragement or relaxation of birth control and the regulation of inunigration, aimed at "a target density and age distribution of the national population". Easier said than done. Favouring law and international protocols rather than tax incentives and mar- ketable pollution permits, he believes that between now and 2050 intelligent intervention can reduce the loss of species to 10 per cent rather than 25 per cent. He espouses an environmental ethic as well as utilitarian arguments "to let no species knowingly die". This splendidly produced, thought-provoking book combines a sparkling survey of evolution and extinction in theory and practice with an optimistic, hard-headed approach to the preservation of biodiversity.

Reviewer: Aaron Segal

Reviewer Info: The late Aaron Segal was Professor of Political Science at the University of Texas at El Paso.