Biodiversity

The immense variety of life on Earth is not limited to the number of species. It exists at every level of biological organisation — from the complex molecules inside a single cell, right up to entire biomes like tropical rainforests or deserts. This all-encompassing heterogeneity is what we call biodiversity.

The term itself was popularised by the sociobiologist Edward Wilson. He used it to describe the combined diversity at all the levels of biological organisation.

The Three Levels of Biodiversity

1. Genetic diversity: A single species can show enormous variation at the genetic level across its distributional range. For example, the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges shows genetic variation in the potency and concentration of the active chemical (reserpine) it produces. India alone has more than 50,000 genetically distinct strains of rice, and 1,000 varieties of mango. This genetic reservoir is the raw material for adaptation and breeding.

2. Species diversity: The diversity at the species level — the number and variety of species in a given area. For example, the Western Ghats have a greater amphibian species diversity than the Eastern Ghats.

3. Ecological diversity: At the ecosystem level, India stands out — with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows, it has a greater ecosystem diversity than a Scandinavian country like Norway. …