Explain classification of plants and animals …

(i) Normal species : species whose population levels are considered to be normal for their survival, such as cattle, sal, pine etc.
(ii) Endangered species : are those which are on the verge of extinction.
For examples-lndian wild ass, Indian rhino, sangai.
(iii) Vulnerable species : are those whose population has declined to levels from where it is likely to move into the endangered category in the near future if the negative factors continue to operate.
Examples-Asiatic elephant, Gangetic dolphin.
(iv) Rare species : are those with small population which move into the endangered or vulnerable species if the negative factors continue to operate.
Examples-Himalayan brown bear, wild Asiatic buffalo.
(v) Endemic species : are those species which are found in some particular areas which are usually isolated by natural or geographical barriers.
Examples-Nicobar pigeon, Andaman wild pig, Mithun in Arunachal Pradesh.
(vi) Extinct species : are those which are not found to exist in a country, continent or the earth.
Examples-Asiatic Cheetah, pink headed duck.