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Despite the alarm with which scientists view this trend, biodiversity has just surfaced on the world's political agenda. The troubles of high-profile animals such as the tiger and rhino grab public attention, while most people hardly see the point of worrying about insects or plants. But extinction is the one environmental calamity that is irreversible. As these lowly species disappear unnoticed, they take with them hard-won lessons of survival encoded in their genes over millions of years.
Only 1.7 million of the estimated 5 million to 30 million different life- forms on earth have been cataloged. Since hundreds of thousands of species may be extinct by the year 2000, the world has neither the scientists nor the time to identify the yet uncounted. "It's as though the nations of the world decided to burn their libraries without bothering to see what is in them," said University of Pennsylvania biologist Daniel Janzen at the TIME conference. Harvard's Wilson called this profligacy the "folly" that future generations are least likely to forgive.
Humanity already benefits greatly from the genetic heritage of little-known species. Some 25% of the pharmaceuticals in use in the U.S. today contain ingredients originally derived from wild plants. Hidden anonymously in clumps of vegetation about to be bulldozed or burned might be plants with cures for still unconquered diseases. "I know of three plants with the potential to , treat AIDS," said Janzen. "One grows in an Australian rain forest, one in Panama and one in Costa Rica."
Nature's diversity offers many opportunities for agriculture, especially now that genetic mapping and engineering have given biotechnology firms the potential power to improve crops by transferring genes from wild strains. According to Wilson, biotechnology can transform a plant into a "loose-leaf notebook" from which scientists can select a particular page. Among the possible results: drought- and frost-resistant crops, and natural fertilizers and pesticides.
Diversity is the raw material of earth's wealth, but nature's true creativity lies in the relationships that link various creatures. The coral in a reef or the orchid in a rain forest is part of an ecosystem, a fragile, often delicately balanced conglomeration of supports, checks and balances that integrate life-forms into functioning communities. Given the complex workings of an ecosystem, it is never clear which species, if any, are expendable.
In the tropics the crucial question is how large a forest must be to sustain itself. If a park or protected area is too small to support some of its animal and plant life, the ecosystem will decline even with protection. As yet, no one knows the minimum critical size of a rain forest, but in 1979 Thomas Lovejoy, now at the Smithsonian Institution, set up a 20-year experiment with the cooperation of the Brazilian government to determine just that for the Amazon region. Among the findings: the smaller the forest, the faster the decline of insects, birds and mammals.