4 • Technologies To Maintain Biological Diversity 



although a few remain skeptical and maintain 

 that this level of concern is based on exagger- 

 ated or insufficient data. 



The abundance and complexity of ecosys- 

 tems, species, and genetic types have defied 

 complete inventory and thus the direct assess- 

 ment of changes. As a result, an accurate esti- 

 mate of the rate of loss is not currently possi- 

 ble. Determining the number of species that 

 exist,' for example, is a major obstacle in assess- 

 ing the rate of species extinction. But use of 

 biological principles and data on land use con- 

 versions have allowed biologists to deduce that 

 the rate of loss is greater than the rate at which 

 new species evolve. 



Reduced diversity may have serious conse- 

 quences for civilization. It may eliminate op- 

 tions to use untapped resources for agricultural, 

 industrial, and medicinal development. Crop 

 genetic resources have accounted for about 50 

 percent of productivity increases and for an- 

 nual contributions of about $1 billion to U.S. 

 agriculture. For instance, two species of wild 

 green tomatoes discovered in an isolated area 

 of the Peruvian highlands in the early 1960s 

 have contributed genes for marked increase in 

 fruit pigmentation and soluble-solids content 

 currently worth nearly $5 million per year to 

 the tomato-processing industry. Future gains 

 will depend on use of genetic diversity. 



Loss of plant species could mean loss of bil- 

 lions of dollars in potential plant-derived phar- 

 maceutical products. About 25 percent of the 

 number of prescription drugs in the United 

 States are derived from plants. In 1980, their 

 total market value was $8 billion. Loss of tropi- 

 cal rain forests, which harbor an extraordinary 

 diversity of species, and loss of deserts, which 

 harbor genetically diverse vegetation, are of 

 particular concern. Consequences to humans 

 of loss of potential medicines have impacts that 

 go beyond economic benefits. Alkaloids from 

 the rosy periwinkle flower [Catharantus roseus], 

 a tropical plant, for example, are used in the 



'Approximately 1.7 million species have been identified. Mil- 

 lions more, however, have yet to be discovered. Recent research 

 indicates that species of tropical insects alone could number 30 

 million. 



Photo credit: H litis 



A foggy, moss- and epiphyte-enshrouded tropical forest 



In Ecuador is about to be cleared for local agriculture, 



a main cause of loss of diversity. 



successful treatment of several forms of can- 

 cer, including Hodgkin's disease and childhood 

 leukemia. 



Although research in biotechnology suggests 

 exciting prospects, scientists will continue to 

 rely on genetic resources crafted by nature. For 

 example, new methods of manipulating genetic 

 material enable the isolation and extraction of 

 a desired gene from one plant or organism and 

 its insertion into another. Nature provides the 

 basic materials; science enables the merging 

 of desired properties into new forms or com- 

 binations. Loss of diversity, therefore, may un- 

 dermine societies' realization of the technol- 

 ogy's potential. 



Another threatening aspect of diversity loss 

 is the disruption of environmental regulatory 



