Q. Definition of Biological diversity?

Biological diversity has no single standard definition. One definition holds that biological diversity is a measure of the relative diversity among organisms present in different ecosystems . "Diversity" in this definition includes diversity within species, among species, and comparative diversity among ecosystems.

Another definition, simpler and clearer, but more challenging, is the totality of genes, species, and ecosystems of a region. An advantage of this definition is that it seems to describe most instances of its use, and one possibly unified view of the traditional three levels at which biodiversity has been identified:

· genetic diversity - diversity of genes within a species. There is a genetic variability among the populations and the individuals of the same species.

· species diversity - diversity among species.

· ecosystem diversity - diversity at a higher level of organization, the ecosystem (richness in the different processes to which the genes ultimately contribute).