With recent indications that fewer than one-tenth of the earth's species of plants and animals have been identified, much less studied for scientific lessons or economic utility, biologists are also calling for a new age of natural exploration, a crash effort to find and study millions of species before they are wiped out.

In recent decades, these scientists say, dramatic progress in molecular biology has stolen status and resources from the task of describing and comparing different forms of life. Too few scientists today are trained in taxonomy, the systematic ordering of species.

Yet knowledge of species diversity is the foundation of ecological understanding, they assert, and also provides the essential raw materials for new genetic engineering technologies. Time is short, they add, because as tropical forests, the most diverse ecosystems on earth, are cleared, thousands of species are possibly being lost each year.