Three levels of biological diversity
Genetic Biodiversity refers to the variation of genes within the species of plants and animals and in fact, the diversity among the genes leads to differentiation of species and which in turn determines the level of Biodiversity.
More genetic diversity helps in the better adaptability of the individuals to the environmental conditions and at the same time, lesser genetic diversity leads to uniformity of species and thus greater susceptibility to the environmental hazards or other related impacts.
This can be understood from the example that People living in hilly areas develop genes in accordance with the climatic condition in long run, as they have wider chest to suck more air from the environment where density of gases is quite low, thus they have diversity in terms of genes from the individuals of same species i.e. Homo Sapiens.
Distinct population of the same species i.e. high variety in the attributes like shape and size of Butterflies, Rhinoceros etc. are due to the possibility of variation among the genes and that is positive for the entire ecosystem too, while we can see low genetic variation among the Cheetah which can be considered as a major reason for them becoming vulnerable.
Species diversity refers to a variety of species in terms of plant, animal and microorganism of a particular ecosystem and species richness (no. of species available in a region) are mostly used to gauge the species diversity.
Species diversity can also be expressed in more precise terms with the help of Taxonomic Diversity which shows the relationship among the species. For example, if at a place x, there are 4 species of reptiles and 2 species of birds while in other place y, there are 6 species of reptiles but no species of birds. Then, the Place x is more taxonomically diverse compared to a place y.
Sometimes Species diversity is used as a synonym to the Biodiversity and the size of the species diversity is instrumental in making food chain longer /shorter. The equatorial rainforest has richest species biodiversity and they are known as the hotspots of the Biodiversity.
As in ecosystem, there are a variety of habitats and Niches (a role and position of species in the environment) for the biological processes and operations, thus the Biodiversity is also considered at the ecosystem level. The examples of ecosystem based on the habitat are Grassland, Coral, Desert, Mangrove, Wetland, Tropical Rain Forest etc.
The Environmental conditions like land, soil, water, climate etc. determine the nature and variation of habitats for different Biological communities and also the change in the Climatic conditions is accompanied by the change in the vegetation. Over the period of time, the species adapt to a particular kind of environment.