complete preparation of biodiversity for class12 cbse exam

1. BIODIVERSITY

2. Astonishing facts
• 20,000 species of ants
• 3,00,000 species of beetles
• 28,000 species of fishes
• 20,000 species of orchids.

3. BIODIVERSITY
• combined diversity at all the levels of
biological organisation- Edward Wilson.
• not only at the species level but at all levels of
biological organisation
• macromolecules→organism→ species
→population→biomes.

4. Types of Biodiversity
• Genetic diversity
• For example: Rauwolfia vomitoria-reserpine
• 50,000 genetically different strains of rice,
• and 1,000 varieties of mango.
• Species diversity
• Western Ghats have a greater amphibian species
diversity than the Eastern Ghats.
• Ecological diversity
• deserts, rain forests, mangroves, coral reefs, wetlands,
• estuaries, and alpine meadows in india than in norway

5. Species on Earth VS India
• 1.5 million plant and animal species on earth.
• No idea of how many species are yet to be discovered
on earth.
• 70 per cent of all the species recorded are animals
• Plants are no more than 22 per cent of the total.
• Among animals, insects are making up more than 70
per cent of the total.
• fungi species in the world is more than the combined
total of the species of fishes, amphibians, reptiles and
mammals.
• not sure about how many prokaryotic species.

6. Species on Earth VS India
• India has only 2.4 per cent of the world’s land
area but species diversity is an 8.1 per cent of
the total.
• 45,000 species of plants and twice as many of
animals are ther in india
• more than 1,00,000 plant species and more
than 3,00, 000 animal species yet to be
discovered

7. Patterns of Biodiversity
• Latitudinal gradients
• Species-Area relationships

8. Latitudinal gradients
• species diversity decreases as we move away
from the equator towards the poles.
• Colombia-equator= 1,400 species of birds
• New York at 41° N= 105 species
• Greenland at 71° N= 56 species
• India(mostly tropical) = more than 1,200
species of birds.