It is a natural habitat that is notified by the state government to be constituted as a National Park due to its ecological, faunal, floral, geomorphological or zoological association of importance. No human activity is permitted inside the national park except the activities permitted by the Chief Wildlife Warden.
Eg: Mudumalia National park in Nilgiris district

Anthropogenic extinctions 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

(i) To create awareness on the degree of threat to biodiversity.
(ii) Provide global index on declining biodiversity.
(iii) Identification and documentation of species at the high risk of extinction.

It is a catalogue of taxa facing risk of extinction. IUCN maintains the Red Data Book. It has eight categories of species.

The International Union for Conservation of Nature (IUCN) is an organization working in the field of nature conservation and sustainable use of natural resources. It was established in 1948 and located at Gland VD, Switzerland.

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.

Species is considered extinct when none of its members are- alive anywhere in the world
Eg.DODO.

Hotspots are areas characterized with high concentration of endemic species experiencing unusual rapid rate of habitat modification loss.
Eg. Western Ghats in India

Co-extinction of a species is the loss of a species as a consequence of the extinction of another.
(Eg. Orchid bees and forest trees by cross pollination).

The non-native or alien species of organisms are called exotic species. They are introduced unintentionally or deliberately as biological control agents for or other uses.
Eg .Tilapia fish from East African Coast has been introduced into Kerala's inland water for its high productivity.

A species that has been categorized as very likely to become extinct is as endangered species.

Excessive exploitation of a species, reduces the size of its population to such a level that it becomes vulnerable to extinction. Dodo has become extinct in the last 200-300 years due to over exploitation by humans

Biodiversity is the variety of life on earth. That is, it is the number of different species of flora and fauna including microorganisms. These organisms can inhabit different ecosystems with, varying conditions like the Rainforests, Coral reefs, Grasslands, Deserts, Tundra, and the Polar icecaps. This variety (Biodiversity) is essential for the wellbeing of our planet and sustenance of life as a whole. The importance of biodiversity can be viewed and measured as:
a)Ecosystem services
b) Biological resources
c) Social benefits of biodiversity
The organization and functioning of ecosystems world over are affected and dependent on biodiversity and its richness. The major functional attributes are:
(i) Continuity of nutrient cycles or biogeochemical cycles (N₂, C, a,o, P, S cycles)
(ii) Soil formation, conditioning or maintenance of soil health (fertility) by soil microbial diversity along with the different trophic members
(iii) Increases ecosystem productivity and provide food resources
(iv) Act as water traps, filters, water flow regulators and water purifiers (forest cover and vegetation)
(v) Climate stability (forests are essential for rainfall, temperature regulation, CO₂ absorption, which in turn regulate the density and type of vegetation)
(vi) Forest resource management and sustainable development
(vii) Maintaining a balance between biotic components
(viii) Cleaning up of pollutants - microbes are the biggest degraders of molecules including many anthropogenic ones which are present in effluents, sewage, garbage and agro-chemicals
(ix) Ecological stability - the varieties and richness of species contribute to ecological stability and survival of species. Biodiverse regions are reservoirs of biological resources like food resources, gene pool, genetic resource, medicinal resources, bioprospecting
(x) To provide unique aesthetic value and hotspots for Ecotourism. Along with forest resources and wildlife, it has commercial significance
(xi) An indicator of the health of the ecosystem. Endemism is a crucial indicator of richness.

(i) Hotspots are areas characterized with high concentration of endemic species experiencing unusual rapid rate of habitat modification loss. Norman Myers defined hot spots as "regions that harbour a great diversity of endemic species and at the same tie, have been significantly impacted and altered by human activities."
(ii) A hotspot is a region that supports at least 1500 endemic vascular plant species (0.5% of the global total) has lost more than 70% of its original vegetation.
(iii) There are 35 biodiversity hotspots in the world. India is home to four biodiversity hotspots. They are:
(1) Himalaya: Entire Indian Himalayan region.
(2) Western Ghats
(3) Indo - Burma: Entire North-eastern India, except Assam and Andaman group of Islands (and Myanmar, Thailand, Vietnam, Laos, Cambodia and Southern China)
(4) Sundarlands: Includes Nicobar group of Islands (and Indonesia, Malaysia, Singapore, Brunei, Philippines).

(i) Keystone species are those which have an extremely high impact on a particular ecosystem relative to its population. They are critical for the overall structure and function of an ecosystem and influence other and plants and animals that make up that ecosystem. Thus in the absence of a keystone species, many ecosystems will fail to exist.
(ii) Predator-prey relationship is an important example. Small Predators that consume herbivorous species prevent such herbivores from destroying the plant species in the ecosystem and are thus considered as keystone species.
(iii) If the number of predators was to decrease, the herbivore population would increase and the plant species in the ecosystem may perish very fast. In turn, the other organisms dependent on plants may also be impacted.
(iv) Thus extinction of a keystone species will lead to loss of biodiversity. Eg. Sea otter is considered to be a keystone species in the nearshore ecosystem. The Kelp forests are critical habitat for many organisms in nearshore ecosystems. These are fed by sea urchins. The Otters feed a Sea Urchins. In the absence of Otters, the sea urchins will destroy the Kelps forest which in turn will impact several other organisms and lead to loss of biodiversity in the ecosystem.