238 



those wild species that are economically significant or are 

 likely to be." Option value is a means of assigning a value to 

 risk aversion in the face of uncertainty. 



Natural habitats preserve a reservoir of continually evolving 

 genetic material — irrespective of whether the values of that 

 material have yet been recognized — that enables the various 

 species to adapt to changing conditions. The plants and animals 

 conserved may spread into surrounding areas where they may be 

 able to be cropped at some future date, or may eventually 

 contribute genetic material to domestic crops or livestock. 

 Protecting natural habitats can therefore be seen as a means for 

 nations ... to keep at least part of their biological resources 

 intact for the future benefit of their populace." (pg. 33-34) 



Other studies also emphasize the immense economic as well as 

 scientific importance of keeping biological options open through 

 preservation of genetic diversity (see for instance the World 

 Resources Institute report Keeping Options Open: The Scientific Basis 

 for Conserving Biodiversity" (1989); Orians, G~. hT^ e~t! al. , The 

 Preservation and Valuation of Biological Resources , Univ. of 

 Washington Press, Seattle, WA (1990)). 



To put economic "option value" into perspective, it should be 

 remembered that only a very small portion of earth's biological 

 heritage has as yet been tapped by humanity for any purpose: 



"Most plants and animals do not now provide direct economic 

 benefits to humans, but this does not mean that those species 

 will never do so. Of the known species of plants and animals, 

 only a small fraction have been examined to determine their 

 potential for new food and drugs or commercial and industrial 

 products. About 10 percent of all plant species contain 

 substances that might be useful in treating cancers, yet few of 

 these species have been examined to assess their potential. Of 

 the approximately 80,000 edible plants, humans have used less 

 than 4 percent, and less than 200 are widely cultivated. A mere 

 seven species — corn, rice, wheat, barley, cassava, potato, and 

 sweet potato — provide three-quarters of all human nutrition. 

 Almost all protein (from domesticated animal species) that humans 

 consume comes from just nine species. Cows and pigs alone 

 provide more than half of all meat production. At the least, 

 this extraordinary reliance on so few species creates a high 

 vulnerability to pests and disease. More important, limited 

 diversity narrows the genetic base, thus reducing opportunities 

 to respond to these pests and disease .... Every time a human 

 contributes to a species' extinction, a range of choices and 

 opportunities is either eliminated or diminished." (from Tobin, 

 R. J., The Expendable Future: U. S. Politics and the Protection 

 of Biological Diversity , Duke University Press (1990), pg. 13) 



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