BIODIVERSITY CH – 12
1. There are more than 20,000 species of ants, 3,00,000 species of beetles, 28,000 species of fishes and nearly
20,000 species of orchids.
2. Biodiversity is the term popularised by the sociobiologist Edward Wilson.
3. In our biosphere immense diversity (or heterogeneity) exists not only at the species level but at all levels of
biological organisation ranging from macromolecules within cells to biomes.
The most important of them are:
(i) Genetic diversity: A single species might show high diversity at the genetic level over its distributional range. The
genetic variation shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be
in terms of the potency and concentration of the active chemical (reserpine) that the plant produces. India has more
than 50,000 genetically different strains of rice, and 1,000 varieties of mango.
(ii) Species diversity: The diversity at the species level. For example, the Western Ghats have a greater amphibian
species diversity than the Eastern Ghats.
(iii) Ecological diversity: At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral
reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like
Norway.
4. According to the IUCN (2004), the total number of plant and animal species described so far is slightly more than
1.5 million
5. Robert May places the global species diversity at about 7 million
6. More than 70 per cent of all the species recorded are animals, while plants (including algae, fungi, bryophytes,
gymnosperms and angiosperms) comprise no more than 22 per cent of the total. Among animals, insects are the
most species-rich taxonomic group, making up more than 70 per cent of the total. That means, out of every 10
animals on this planet, 7 are insects
7. biodiversity is depicted showing species number of major taxa.
1. There are more than 20,000 species of ants, 3,00,000 species of beetles, 28,000 species of fishes and nearly
20,000 species of orchids.
2. Biodiversity is the term popularised by the sociobiologist Edward Wilson.
3. In our biosphere immense diversity (or heterogeneity) exists not only at the species level but at all levels of
biological organisation ranging from macromolecules within cells to biomes.
The most important of them are:
(i) Genetic diversity: A single species might show high diversity at the genetic level over its distributional range. The
genetic variation shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be
in terms of the potency and concentration of the active chemical (reserpine) that the plant produces. India has more
than 50,000 genetically different strains of rice, and 1,000 varieties of mango.
(ii) Species diversity: The diversity at the species level. For example, the Western Ghats have a greater amphibian
species diversity than the Eastern Ghats.
(iii) Ecological diversity: At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral
reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like
Norway.
4. According to the IUCN (2004), the total number of plant and animal species described so far is slightly more than
1.5 million
5. Robert May places the global species diversity at about 7 million
6. More than 70 per cent of all the species recorded are animals, while plants (including algae, fungi, bryophytes,
gymnosperms and angiosperms) comprise no more than 22 per cent of the total. Among animals, insects are the
most species-rich taxonomic group, making up more than 70 per cent of the total. That means, out of every 10
animals on this planet, 7 are insects
7. biodiversity is depicted showing species number of major taxa.
