||"Journalists can look to the U.S. Commerce Department each month to keep score on trade. Economic scorekeeping on the environment is in its infancy. Whenever fines are enforced, U.S. factories do a better job of monitoring pollution emmisions. World Bank economists, among others, have begun to find ways of assessing a country's deforestation, oil depletion and soil erosion and of deducting that cost from GNP. But some aspects of the environment are not so easily measured. How, for instance, does one price a sunset? And, more to the point of this essay, how does one determine the worth of an individual species? The value of particular genes in a particular species can changes. Horses with genes for strength were desired a century ago when farmes used them to plow fields and pull buggies, but not now. Moreover, one cannot consider species alone; they exist as part of an entire eco-system."