Biodiversity: Nature and Importance of Biodiversity!
Biodiversity or biological diversity refers to the variety of life on earth. The term encompasses three categories: genetic diversity, species diversity and ecosystem diversity. ‘Genetic diversity’ describes the variation of genes within a species, ‘species diversity’ describes the variety of species within region, and ‘ecosystem diversity’ refers to the number and distribution of ecosystems.
The increasing interest in biodiversity is the result of concerns regarding species extinction, depletion of genetic diversity, and disruptions to the atmosphere, water supplies, fisheries and forests.
The environment is a complex of ecosystems made up of a variety of species, themselves represented by a number of strains, each with its own genetic identity. This diversity is a condition for the long-term sustainability of the environment and the maintenance of its integrity is, therefore, recognized as being indispensable to sustain human life.
The taxonomic knowledge of species is incomplete and, therefore, it is essential to guard against the extinction of the largest possible number of species and strains, some of which, in the future, may provide us with food and medicine or can be used in the biological control of pests and pathogens.
Biological diversity encompasses all species of plants, animals and micro-organisms and the ecosystem and ecological processes of which they are part. Genetic diversity is the sum total of genetic information, contained in the genes of individual plants, animals and micro-organisms that inhabit the earth. Species diversity refers to the variety of the living organisms on earth.
Ecosystem diversity refers to the variety of habitats biotic communities and ecological processes in the biosphere as well as the enormous diversity within ecosystems in terms of habitat difference and the variety of ecological processes.
Biodiversity provides the basis for life on earth. The fundamental social, ethical, cultural and economic values of these resources have been recognized in religion, art and literature from the earliest days of recorded history. Wild species and the genetic variations within them make substantial contribution to the development of agriculture, medicine and industry.
Perhaps, even more important, many species have been fundamental to stabilization of climate, protection of watersheds, protection of soil, and the protection of nurseries and breeding grounds. It is difficult to determine the total economic value of the full range of goods and services which biodiversity provides.
Biological resources have made substantial contribution to human welfare, especially in the rural areas of developing countries. For example, fuel wood and dung provide over 90 per cent of the energy needs in many areas in Nepal, and in many other countries. Human beings have used about 7,000 kinds of plants for food, but only 20 species supply 90 per cent of the world’s food, and just three—wheat, maize and rice—supply more than half.
Although the major food crops in use today were domesticated thousands of years ago, the potential for other species to play prominent role in world agriculture is great. Numerous locally important, though yet much less known species of wild and domesticated plants could be cultivated and used much more widely.
Genetic diversity of a crop is the total genetic variation of the species available for further crop improvement. With an ever-increasing growth in human population, more food has to be grown to satisfy the needs.
The key to better yielding varieties is provided by plant breeding to increase their food value, resistance to fungal, bacterial and viral diseases and insects, nematodes and other pests. This inbuilt genetic resistance and adaptation may eliminate the need for environmentally undesirable pesticides.
More than four lakh varieties of germplasms of important crops have been collected in international gene banks. Some countries, including India, have specific crop gene banks. There are numerous facilities in the world that conserve collection of vegetative propagated crops like fruit trees, tuberous crops, palms, nuts coffee, cocoa, grasses and shrubs. World collection also includes varieties of wheat, rice, maize, barley, potatoes, sweet potatoes, sorghum, millets, lentils, legumes, etc.