Biodiversity and Conservation

The levels and value of biodiversity, why it is being lost, the IUCN categories of threatened species, and how it can be conserved.

Key ideas

Biodiversity is the variety of life in a region at three levels: genetic, species and ecosystem diversity.
It is richest in the tropics, which get more sunlight and water; tropical rain forests hold about half of all species.
Biodiversity has ecological, economic and scientific roles: it cycles matter, gives food and medicines, and shows how life evolved.
It is lost through habitat destruction, over-exploitation, pollution, exotic species, poaching and natural calamities.
The IUCN Red List groups threatened species as endangered, vulnerable or rare.
Conservation means protecting habitats, saving crop and livestock varieties, regulating wildlife trade and involving local people.
Hotspots are species-rich, vulnerable areas; mega diversity centres are tropical countries such as India, Brazil, Indonesia and Madagascar.

Species on the earth	about 10 million
Extinct	about 99% of all species that ever lived (1% survive)
Madagascar	about 85% of its plants and animals found nowhere else
Percentage of a total	per cent × total ÷ 100
Endangered, vulnerable, rare	in danger of extinction / likely to be endangered soon / very small populations
India’s wildlife law	Wild Life (Protection) Act, 1972

Mixing up vulnerable (may become endangered) and rare (very few, in a small area).
Thinking exotic species are rare local ones: they are brought in from outside.
Saying biodiversity is richest near the poles.

About 99 per cent of all species that ever lived are extinct. If 66,000 species of a group ever lived, how many survive and how many are extinct?

Working: 1% and 99% of 66,000

Answer: 660 survive; 65,340 are extinct