38 • Technologies To Maintain Biological Diversity 



Box 2- A. — Components of Biological Diversity 



Genetic characteristics are the features of 

 plants and animals that are passed from one 

 generation to the next through the mecha- 

 nism of genes. Genes control the chemistry 

 and structure of whole organisms; there- 

 fore, the greater the diversity of genes, the 

 greater the chance of having some individ- 

 uals that can survive gradual environmental 

 changes and a greater chance of having po- 

 tential direct utility for people. 

 Species is a taxonomic category ranking im- 

 mediately below genus and including closely 

 related, morphologically similar individuals 

 that actually or potentially interbreed. 

 Habitat is the place where a species finds 

 the required combination of food, cover, 

 water, and other resources to meet its bio- 

 logical needs. Each species is adapted gen- 

 erally to a specific arrangement and amount 

 of essential resources. 

 A population is a subset of all the individ- 

 uals of one species. It consists of individ- 

 uals that are found in a distinct portion of 

 the species range that interbreed with some 

 regularity. Thus, the members of a popula- 



tion share a common set of genetic charac- 

 teristics. Populations can have some char- 

 acteristics not found in other populations 

 of the same species, in which case such 

 terms as subspecies, variety, or breed are 

 used to describe them. 

 A community is a collection of species 

 present in one place at one time. Most com- 

 munities contain groups of species that in- 

 teract in a variety of ways. There are usu- 

 ally two consequences of these interactions: 

 1) certain species cannot be maintained 

 without other interacting species; and 2) 

 some species so strongly affect other spe- 

 cies that the community changes signifi- 

 cantly if that species is removed. 

 Communities are part of a higher level of 

 organization called ecosystems. An ecosys- 

 tem is a dynamic complex of plant and ani- 

 mal communities, which along with their 

 abiotic environment, constitutes one func- 

 tioning whole. An understanding of eco- 

 system functioning can greatly influence 

 the kinds of conservation and management 

 applied. 



Table 2-1.— Examples of Benefits From Ecosystem, Species, and Genetic Diversity 



Ecological processes 



Research 



Cultural heritage 



Recreation and tourism 



Agriculture and 

 harvested resources 



Ecosystem diversity 



Maintenance of produc- 

 tivity; buffering environ- 

 nnentai changes; watershed 

 and coastal protection 



Species diversity 



Role of plants and animals 

 in forest regeneration, 

 grassland production, and 

 marine nutrient cycling; 

 mobile links; natural fuel 

 stations 



Genetic diversity 



Raw material of evolution 

 required for survival and 

 adaptation of species and 

 populations 



Natural research areas; 

 sites for baseline monitor- 

 ing (e.g., Serengetl National 

 Park, Zambesi Teak Forest) 



Models for research on hu- 

 man diseases and drug 

 synthesis (e.g., bristlecone 

 pine, desert pupfish, me- 

 dicinal leeches) 



Fruit flies in genetics, corn 

 in inheritance, and Nico- 

 tiana in virus studies 



Sacred mountains and 700 to 800 million visitors 

 groves; historic landmarks per year to U.S. State and 

 and landscapes (e.g., national parks; 250,000 to 

 Mount Fuji; Voyageurs Park, 500,000 visitors per year to 

 Minnesota) mangrove forests in Ven- 



ezuela 



National symbols (bald ea- 

 gles); totems; objects of 

 civic pride (e.g., port orford 

 cedar, bowhead whale, Fi- 

 cus religiosa) 



Breeds and cultivars of 

 ceremonial, historic, es- 

 thetic, or culinary value 

 (e.g., Texas longhorn cattle, 

 rice festivals (Nepal)) 



95 million people feed, ob- 

 serve, and/or photograph 

 wildlife each year; 54 mil- 

 lion fish; 19 million hunt 



100,000 visitors per year to 

 Rare Breeds Survival Trust 

 in the United Kingdom 



Rangelands for livestock pro- 

 duction (e.g., 34 in the U.S.); 

 habitats for wild pollinators 

 and pest enemies (e.g., sav- 

 ing $40 to $60 per acre for 

 grape growers) 



Commercial logging, fishing, 

 and other harvesting indus- 

 tries ($27 billion/year in U.S.); 

 new crops (e.g., kiwi fruit, red 

 deer, catfish, and loblolly 

 pine) 



Required to avoid negative 

 selection and enhancement 

 programs; pest and disease 

 resistance alleles 



SOURCE: Office of Technology Assessment, 1986. 



