by Edward O. Wilson

About the author: Edward O. Wilson, a noted authority on biology and the evolution of behavior, is a research professor at Harvard University and the author of many books.

Known as the biosphere to scientists and as the creation to theologians, all of life together consists of a membrane around earth so thin that it cannot be seen edgewise from a satellite yet so prodigiously diverse that only a tiny fraction of species have been discovered and named. The products of billions of years of evolution, organisms occupy virtually every square centimeter of the planet’s surfaces and fill nearly every imaginable niche.

Biologists estimate that more than half the species occur in the tropical rain forests. From these natural greenhouses, many world records of biodiversity have been reported&mdash...