The term refers to the variety of life on earth.It demonstrates the extent of variation at different levels of species,genetic and ecosystem in a community of organisms.
It not equal in its distribution on earth;but rather varies with the type of ecosystem available and the distribution of biotic and abiotic factors in the ecosystem. For example;
It is highest in the Tropics,due to the species richness and diversity of the region. However, it varies in other ecosystem based on species diversity peculiar to parts of the region .e.g it is highest in the marine ecosystem along the coast of abundant temperature for primary producers.