Levels of biodiversity

What is biodiversity?

Biodiversity refers to the variety and variability among all groups of living organisms and the ecosystem complexes in which they occur.

In the Convention of Biological Diversity (1992), biodiversity has been defined as the variability among living organisms from all sources including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part.

 Levels of biodiversity

In many range from the genetic level within a species to diversity found in different biomes based on which three categories of biodiversity recognised:

1. Genetic diversity

When the genes within the same species show different versions due to new combinations, it is called genetic variability or diversity.

It is the basic source of biodiversity. The genes found in organisms can form enormous number of combinations each of which gives rise to some variability. Genes are the basic unit of hereditary information transmitted from one generation to to other. For example, all rice variety is belong to the species Oryza sativa, there are thousands of of wild and cultivated right is of rise which show variation at the the genetic level and differ in their colour, size, shape, aroma and nutrient content of the grain. This is the the genetic diversity of rice.

2. Species diversity 

 It is the basic source of biodiversity. The genes found in organisms can form enormous number of combinations each of which gives rise to some variability. Genes are the basic unit of hereditary information transmitted from one generation to to other. For example, all rice variety is belong to the species Oryza sativa, there are thousands of of wild and cultivated right is of rise which show variation at the the genetic level and differ in their colour, size, shape, aroma and nutrient content of the grain. This is the the genetic diversity of rice.

2. Species diversity 

This is the variability found within the population of a species or between different species of a community.

It represents broadly the species richness and their abundance in a community. There are two popular indices of measuring species diversity e known as Shannon wiener index and Simpson index. 

What is the number of species on this biosphere? The estimates of actual number vary widely e due to incomplete and indirect data. the estimates given by Wilson in 1990 to put the total number of living species in a range of 10 million to 50 million. Till now only about 1.5 million living and 300000 fossil species have been actually described and given scientific names. It is is quite likely that a large fraction of these species may become extinct even before they are discovered and enlisted.

3. Ecosystem diversity

This is the diversity of ecological complexity showing variations in physical characters, ecological niches, trophic structure, food - webs, nutrient cycling etc.

The ecosystem variations with respect to physical parameters include moisture, temperature, altitude, precipitation etc. Thus, there occurs tremendous diversity within the ecosystems, along these gradients.

We may consider diversity in forest ecosystem, which is supposed to have mainly dominance of trees. But, while considering a tropical rainforest a tropical decidous forest, a temperature decidous forest and a boreal forest, the variations observed are just too many and they are mainly due to variations in the above-mentioned physical factors.

The ecosystem diversity is of Great value that must be kept intact. This diversity has developed over millions of years of evolution. If we destroy this diversity, it would disrupt the ecological balance. We cannot even replace the diversity e of one ecosystem my that of another. Coniferous trees of boreal forests can not kept up the function of the trees of tropical deciduous forest lands and vice versa, because ecosystem diversity has evolved with respect to the prevailing environmental conditions with velveleta ecological balance.