Lesson 1 of 12 · 7 min

What biodiversity is

NCERT §13.1

For the last unit of the year, Ma'am Deshpande hands the survey group a blank notebook: they are to start a biodiversity register for a sacred grove in the Sahyadri hills near Pune.

The story this chapter follows: Rohan's biodiversity register

Rohan, the Class 12 student from Pune who counted populations at the lake and then studied it as an ecosystem, closes the year with one more project. Ma'am Deshpande's survey group is to start a biodiversity register for a sacred grove in the Sahyadri hills: what lives there, why it is rich, what threatens it and how it can be saved. Each page of the register is one part of this chapter.

The lesson in notes

In short

Life is staggeringly varied. Known species include more than 20,000 kinds of ants, about 3,00,000 kinds of beetles, 28,000 of fishes and nearly 20,000 of orchids.

Diversity exists at every level of biological organisation, from macromolecules inside cells up to biomes. The sociobiologist Edward Wilson popularised the word biodiversity for this combined diversity.

Genetic diversity: one species can vary widely at the genetic level across its range. Rauwolfia vomitoria from different Himalayan ranges differs in the potency and concentration of the reserpine it makes.

Two examples of genetic diversity from India: over 50,000 genetically distinct rice strains, and 1,000 varieties of mango.

Species diversity: the Western Ghats hold a greater diversity of amphibian species than the Eastern Ghats.

Ecological diversity: India holds deserts, rain forests, mangroves, coral reefs, wetlands and estuaries, and alpine meadows too, so its ecosystem diversity is greater than that of a Scandinavian country such as Norway.

Millions of years of evolution built this diversity, yet at the present rate of species loss it could be gone in less than two centuries, which makes its conservation a matter of international concern.