Biodiversity and Conservation

Lesson

Part 1 — the variety of life, how it is distributed, and why it matters.

In this lesson you will

Describe genetic, species and ecological diversity with examples
Estimate global and Indian species numbers
Explain latitudinal gradients and the species–area relationship
Explain why species diversity matters to ecosystems

Concept

Three levels of diversity

Diversity exists within species, among species and among ecosystems.

Table of the three levels of biodiversity with Indian examples
Level	Example
Genetic diversity	Rauwolfia vomitoria in different Himalayan ranges varies in the potency and concentration of reserpine; India has more than 50,000 strains of rice and 1,000 varieties of mango
Species diversity	The Western Ghats have a greater diversity of amphibian species than the Eastern Ghats
Ecological diversity	India’s deserts, rain forests, mangroves, coral reefs, wetlands, estuaries and alpine meadows give greater ecosystem diversity than a Scandinavian country such as Norway

Diagram

How many species?

The IUCN (2004) put the number of described plant and animal species at slightly more than 1.5 million. Robert May estimated the global total at about 7 million. More than 70 percent of recorded species are animals; plants make up no more than 22 percent. Among animals, insects are the most species-rich group.

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