The Richness of Biodiversity

The exact number of species existing on the Earth is not known to anyone.

There are only estimates and these numbers also keep on changing with time because new species get added to the list of known species.

Some estimates put the number of species between 5 to 50 million whereas the others predict it to be somewhere between 1.4 million to 100 million. As per year 2000 data, only 1.7 million species have been described.

About half of the world’s total species are present in just 7% of the land area. Thus, the distribution of species is not uniform. It is estimated that the tropics∖alone have 5 million species.

In fact, insects and plants constitute most of the species. Many of the insects are tropical beetles of rain forests. Mammals, however, form only a small fraction and the number of species of mammals is about 4000.

The diversity of species involves genetic diversity, habitat diversity or species diversity. The genetic diversity refers to the total number of genetic characteristics where as the habitat diversity is the diversity of habitats per unit area. The species diversity further comprises species richness, species evenness and species dominance. The species richness indicates the total number of species, the species evenness means relative abundance of species and the species dominance signifies the most abundant species.

The distribution, more particularly the uneven distribution Ofbiodiversity, is a result of variation in climatic conditions, environmental factors, location of a place or a habitat and human interference and activities. The natural relationships between species, i.e. competition, symbiosis, predation, dominance etc. also govern the diversity.

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