Biodiversity & its conservation P-2

Number of species on earth

It is difficult to believe that there are

• 20,000 species of orchids,
• 20,000 species of ants
• 28,000 species of fishes and
• about 3,00,000 species of beetles on earth,

According to IUCN

(International Union for Conservation of Nature and Natural resources) estimates number of animal and plant species, described so far, is more than 1.5 million.
Due to project ‘Species 2000’ and ‘Global Biodiversity lnformation’, the new species are being discovered faster than ever before. However, the discovery and description of species is more complete in temperate than in tropical countries. A large number of species are waiting to be discovered from tropics.
According to estimates of Robert May

• The global species diversity is about 7 million (1.5 million, i.e. 22% reported till now and 78% are yet to be discovered).
• More than 70% of all the species recorded are animals. Plants are not more than 22% of the total.
• Among animals also, about 70% are insects.
• The Fungi have more species than all the vertebrates species combined.
• In case of vertebrates, the species of fishes are more than that of birds, and of latter, more than reptiles.
• In case of plant species, the species of fungi > species of angiosperms > species of algae.

The all above estimates do not give any idea for the number of species of prokaryotes, whose species diversity may run in millions.
Number of species In India
India is one of the I2 mega diversity country of the world. It has 2.4%, i.e., 1/40 of world land area, but global species diversity is 8.1 %, i.e. l/ 12.
 In India the number of animal and plants species recorded so far is 90,000 and 45,000 respectively.
According to May’s global estimates, about 3,00,000 animal species and 1,00,000 plant species are yet to be discovered.
(A large number of species are facing the threat of extinction even before they are Discovered)

India’s world Ranking

Number of Species in India

Mammals                               8th                                                       350                                   Birds                                        8th                                                      1200                               Reptiles                                   5th                                                       453                                   Amphibia                               15th                                                      182                                 Angiosperms                       15th-20th                                               14,500

• It is estimated that 18% of Indian plants are endemic to the country and found nowhere else in the world.
• Among the plant species the flowering plants have a much higher degree of endemism, a third of these are not found elsewhere in the world.
• Among amphibians found in India, 62% are unique to this country.
• Among lizards, of the 153 species recorded, 50% are endemic.

High endemism has also been recorded for various groups of insects, marine worms, centipede