In the Convention on Biological Diversity signed by many member states at the Earth Summit held in Rio de Janeiro (Brazil) in 1992, explains biodiversity as follows:
“Biological diversity” means the variability among living organisms from all sources including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.
Biodiversity is a generic term that can be related to many environments and species, for example, forests, freshwater, marine and temperate environments, the soil, crop plants, domestic animals, wild species and microorganisms.
Basically it can be classified according to three types of diversity:
Ecosystems and landscapes (habitat diversity) animal, plant, bacterial species (species diversity) all genes (genetic diversity). Of particular importance are the taxonomically isolated species, as they have little similarity to other species and therefore are unique with respect to their genetic structure.
These species are often endemic meaning limited to one specific area. Their extinction would mean a greater loss for global biodiversity rather than just the extinction of a species. Biodiversity has been an important aspect of human existence. Perhaps the most important value of biodiversity, particularly in a country like India, is that it meets the basic survival needs of a vast number of people.
Even today there is any number of traditional communities which depend, wholly or partially, on the surrounding natural resources for their daily needs of food shelter, clothing, household goods, medicines, fertilizers, entertainment etc. Among the other benefits of biodiversity, an important one that comes to our mind relates to the conservation of food chain.
Each species in a food web is dependent on the other. The loss of any one species therefore, may unleash a chain reaction where many known and unknown life forms would vanish altogether. The importance of biodiversity in maintaining a food chain in itself speaks a lot about its potential. The two documented benefits of biodiversity are:
i. Consumptive and productive uses grains, vegetables, fruits, plants, medicines, timber, oils, forest products, milk products, eggs, the list of items on this account is endless;
ii. Non-consumptive benefit where we have biodiversity’s role in providing raw materials for biotechnology, regulation of water and other nutrient cycles, regulation of climatic conditions, carbon fixation etc.
The economic value of biodiversity is also of great benefit. Each species is of potential value to humans. So are healthy ecosystems. The global collection of genes, species, habitats and ecosystems is a resource that provides for human needs now, and is essential for human survival in the future. Human depend on other species for all of their food and for many medicines and industrial products.
Up to 80 per cent of the people in developing countries depend on traditional medicine for primary health care, most of which is derived from plants and some from animal and mineral sources. About 20,000 species of plants are used for medicinal purposes in these countries. Nearly one-quarter of all prescription drugs used in the developed world are based on plants, including 21 indispensable mainstream drugs.
These include aspirin from the plant Filipendula ulmaria and Quinine from the bark of several species of the Cinchona tree. In addition, plants contain complex chemical structures which may be possible to synthesise in a laboratory, and which might provide important clues for new medicines. Genetic diversity is important in breeding crops and livestock.