‘Biological diversity’ or biodiversity is that part of nature which includes the differences in genes among the individuals of a species, the variety and richness of all the plant and animal species at different scales in space, locally, in a region, in the country and the world, and various types of ecosystems, both terrestrial and aquatic, within a defined area.

Biological diversity deals with the degree of nature’s variety in the biosphere. This variety can be observed at three levels -

1. the genetic variability within a species,
2. the variety of species within a community, and
3. the organisation of species in an area into distinctive plant and animal communities constitutes ecosystem diversity.