. . Extinction Species is considered extinct when none of its members are alive anywhere in the world. If individuals of a species remain alive only in captivity or other human controlled conditions, the species is said to be extinct in XII Std Zoology Chapter XII Std Zoology Chapter Biodiversity and its Conservation the wild.
In both of these situations, the species would be considered globally extinct. A species in considered to be locally extinct when it is no longer found in an area it once inhabited but is still found elsewhere in the wild. In the million years of life on Earth, there had been mass extinctions, which had eliminated at least % of the species of flora and fauna on the globe. The extinction of species is mainly due to drastic environmental changes and population characteristics.
There are three types of Extinctions i. Natural extinction: It is a slow process of replacement of existing species with better adapted species due to changes in environmental conditions, evolutionary Project Tiger: The Government of India launched the ‘Project Tiger’ in to protect our national animal. From tiger reserves since its inception, the Project Tiger coverage has increased to at present. Project Tiger is an ongoing Centrally Sponsored Scheme of the Ministry of Environment and Forests, providing central assistance to the states for tiger conservation in designated tiger reserves.
Project Tiger was launched in the Jim Corbett National Park, Uttarakhand in1973. The project ensures a viable population of Bengal tigers in their natural habitats, protecting them from extinction and preserving areas of biological importance as a natural heritage. The National Tiger Conservation Authority (NTCA) is a statutory body of the Ministry, created under the Wildlife (Protection) Act, . India holds over half the world’s tiger population.
According to the latest tiger census report released on 20th January by NTCA, the current tiger population is estimated at , . changes, predators and diseases. A small population can get extinct sooner than the large population due to inbreeding depression (less adaptivity and variation). ii.
Mass extinction: The earth has experienced quite a few mass extinctions due to environmental catastrophes. A mass extinction occurred about million years ago during the Permian, where % of shallow water marine invertebrates disappeared. iii. Anthropogenic extinction: These are abetted by human activities like hunting, habitat destruction, over exploitation, urbanization and industrialization.
Some examples of extinctions are Dodo of Mauritius and Steller’s sea cow of Russia. Amphibians seem to be at higher risk of extinction because of habitat destruction. The most serious aspect of the loss of biodiversity is the extinction of species. The unique information contained in its genetic material (DNA) and the niche it possesses are lost forever.