I. Biological diversity can be simply defined as the variety in living organisms . Genetic diversity is made up of gene-based traits below the species level including subspecies, varieties, and ecotypes.
Richness is the number of species.
Landscape or ecological diversity is the variety and arrangement of ecological community types in real-world geographical space. Some species are found only in ecotones - the space between community types. Novel survival opportunities or ways to exploit the environment are created when many different elements of habitats are brought together in close proximity. The persistence of life on the planet earth depends on diversity. Most organisms that go extinct have reached a critically low level of diversity.