Biodiversity stands for all living things on earth. It refers to the range of variations among a set of entities and is commonly used to describe variety and variability of living organisms in terms of genetic diversity (heritable variations within populations), species diversity (species richness in a habitat) and ecological diversity (biophysical diversity). India, because of its unique biogeographic location embraces three major biological realms, viz. Indo-Malayan, Eurasian and Afro-tropical. It is notable in its species-richness and endemism, and is ranked tenth amongst the biodiversity-rich countries. India is one of the world's 12 Vavilovian centres of origin and diversification of cultivated plants (with 167 species of agrihorticultural crops and 320 species of their relatives known to have originated here). Conservative estimates of species-richness show that around 127,000 species (plants, animals and microorganisms) have been so far reported from India and 400,000 species are yet to be explored (Roy et al., 2002). Biodiversity also occurs at a genetic level. In other words, even within a single species there is variation. This is known as genetic biodiversity. Different populations of the same species can differ in their genetic profiles. It is this genetic biodiversity which facilitates the breeding of different varieties of plants and animals. Diversity in genes provides the basis for continued survival of the species in view of the changing environment. |
