species ctintinues, despite protective legislation, hut 

 these effects are dwarfed hy hahitat destruction. Hahi- 

 tat destruction causes an indiscriminate loss of species 

 throughout an ecosystem, not only the meaty, attrac- 

 tive, or threatening targets of human exploitation. All 

 species need a place to live, and many exhibit adapta- 

 tions that intricately hind them to specific hahitats or 

 to particular biological associations within habitats 

 (e.g., many forest trees and the hats or rodents that 



The disappearance of this diversity has unfathom- 

 able consequences for human beings. Tropical diversity 

 represents a storehouse of potential human applica- 

 tions, hut one being looted and vandalized by uncon- 

 trolled development. Few people realize that almost all 

 of the world's agriculture involves only 25 species of 

 plants (one ten-thousandth of the species we've identi- 

 fied). Nor do many appreciate the constant threat to 

 agricultural production or human health posed by new- 



Deforestation In ttie upper Amazon Basin of Rondonia, Brazil, termed "an environmental holocaust" by a recent National Geographic 

 article. Field [Museum mammalogists and ornithologists conducted biological Inventories at a nearby dam site on the Rio Jl-Parana In late 

 1986. Their work provides a baseline against which future degradation can be assessed, as well as information to mitigate the effects of 



construction. PnotobyB D Pattefson 



20 



pollinate their flowers or disperse their seeds) . When 

 the habitat disappears, so do all the species that inhabit 

 it. Scientists estimate that rates of extinction caused hy 

 habitat destruction are at least a thousand times greater 

 than normal "background" extinctions. Daniel Sim- 

 berloff of Florida State University predicts that as many 

 as two-thirds of all tropical species will go extinct 

 through deforestation over the next 150 years. 



ly appearing pathogens and parasites. Fewer still are 

 aware that many "wonder drugs" of modem medicine 

 (including penicillin, atropine, and digitalis, among 

 many others) are compounds "invented" and produced 

 by species in nature. Our daily reliance on biological 

 materials and understanding will increase dramatically 

 over the next century. As human populations treble (to 

 an estimated 1 1 billion) by the year 2100, food produc- 



