Biology 2 Marks Questions

In-situ Conservation : In this method, organisms are conserved mainly in their natural habitat where abundant biodiversity exists. From conservation point of view, these habitats are declared as protected areas. Example : National park, Sanctuaries, Biosphere reserves, sacred grooves and lakes, etc. have been created for this conservation purpose.

According to organic farmers, biodiversity improves the health of crop plants because the more diverse the crop, the more sustainable it will be. Organic farmers therefore work to create a system where mosquitoes, sometimes called insects, can not be eliminated but are instead kept at manageable levels by a complex system of checks and balances to maintain biodiversity. Bio-control is thus a holistic approach to the interactions between billions of forms of life and this provides greater stability to the ecosystem. Fields can be developed as habitats and habitats for predators and prey throughout their life cycle.

(a) The mass extinction of species since the origin and diversification of life on earth has been happened for five times earlier. Currently, the sixth extinction is in progress.
(b) It is also true that the current rate of extinction is estimated to be 100 to 1000 times faster than the extinction before the existence of human and. Human activities are responsible for this rate. If the current rate of extinction continues like this, then in the coming 100 years, half of the species on Earth will be extinct.

The stability of the community depend on species as demonstrated by David Tilman experiment in the following way :
(a) The productivity of a stable community does not vary much from year to year.
(b) It must be either resistance to natural or man made occasional disturbance.
(c) It also has resistant to invision by alien species.

Co-extinction : When a species becomes the plant and animal species dependent on it in an obligatory way also begin to extinct. For example, when a host fish species become extinct the survival of its specific parasites also get threatened. Another example that we know is the pollination of a specific plant by a specific insect and if this plant species anyhow become extinct, the insect dependent for completion of its life cycle will undoubtably become extinct i.e. Yucca plant is pollinated by Pronuba yuccasella. Therefore, extinction of will definitely cause the extinction of this moth.

Human has destroyed the natural habitat and fragmented them to fulfil their requirement. He has been exploiting the natural resources beyond his limit although he knows that without this biodiversity, his survival will be threatened. Destruction and fragmentation of habitat to accommodate expanding population, manmade disturbances like fire, tree fell, pollution, introduction of alien species are the anthropogenic activities causing rapid species extinction. The current rate of extinction is estimated to be 100 to 1000 times faster than the extinction before the existence of human and human activities are responsible for this rate. If the current rate of extinction continues like this, then in the coming 100 year, half of the species on Earth will be extinct.

If the Tropical rainforest would have been from the present 6% areas of earth to 12% areas, it will promote the increase in biodiversity. In Tropical rainforest, millions of species inhabit and mutually interact with each other providing complex food web through several interwoven interdependent food chains and we know that higher be the number of trophic level in a ecosystem, greater will be its stability.

Ants are omnivorous creatures, which work like scavengers by consuming food items, dead animals, etc. If the species of ants are reduced from 20,000 to 10,000, then the amount of substances that they eat, will increase. The animals who prey the ants, will remain hungry because of insufficient availability of food and will die due to mutual conflict, that is, there will be a disruption in the food chain, the ecosystem will become unbalanced, which adversly affect the entire life. 

Biodiversity hotspots refers to the region with very high level of species richness and high degree of endemism (that is species confined to that region and not found anywhere else). At present total 34 hotspots have identified in the world however these hotspots are also facing rapid declination of due to Habitat loss three of these hotspot are western ghat, Indo-Burma and Himalaya. Although all the biodiversity hotspot put together cover less than the 2% of the earth land area, the number of species they collectively harbour, is extremely high and strict production of these hotspots could reduce the ongoing extinction by almost 30%.

Earth summit at Rio de Janeiro (1992), Brazil promoted convention on biological diversity which was signed by 152 Nations. Its recommendations came into effect on 29th December 1993. India became a party to this convention on biological diversity in May 1994. The various commitments were : (a) Adoption of ways and means to conserve biodiversity.
(b) Managing biodiversity for sustainable uses.
(c) Ensuring equitable sharing of benefits from biological diversity including utilisation of genetic resources.
A second world summit was held in 2002 in Johannesburg, South Africa. 199 countries attending the Summit pledged to significantly reduce the current rate of biodiversity loss at global, regional and local levels by 2010.

Since the vedic period, man has been receiving something or the other from nature to fulfil his purposes. The earth's rich biodiversity is vital for the survival of mankind. The reasons for conserving biodiversity are narrowly utilitaria, broadly utilitarian and ethical. Besides the direct as food, fibres, firewoo pharmaeuticals etc. there are many indirect benefits we receive through ecosystem services such as pollination, pest control, climate moderation and flood contro therefore it becomes our moral responsibility to take good care of Earth's biodiversity and pass it on in good order to our next generation.

Red Data Book : The book in which information about the endangered species of the world whose protection needs to be taken care of, is printed on red pages. It is a catalogue of taxa facing the risk of extinction. The first edition of this book was published on January 1, 1972. The uses of the red data Book are :
(a) Developing awareness about the importance of threatened biodiversity. 
(b) Identification and documentation of endangered species.
(c) Providing a global index of the decline of biodiversity.
(d) Defining conservation priorities at the local level and guiding conservation action.
According to the red data book in India, 44 plant species are critically endangered, 113 endangered and and 87 vulnerable, amongst animal, 18 are critically endangered, 54 endangered and 143 vulnerable.

Keeping in mind the rapidly decreasing rate of biodiversity in the world, the International Organization for Conservation of Nature and Natural Resources (IUCN) was formed in 1948. lt it has its headquarter at Morges, Switzerland. The first edition of this book was published on January 1, 1972. A total of five editions of this book have been published so far. The IUCN maintains a Red Data Book which is a catalogue of taxa that are facing the risk of extinction.

Coral reefs are large-sized calcareous structures whose upper surface is located near the surface of the sea. It is made of calcium carbonate and is produced by the polyps of animals of the class Anthozoa of the phylum Colenetrata of invertebrate animals. Coral reefs are found in the world.
Corals are the most fertile ecosystems within the ecosystems. They develop in warm shallow environments and provide support to an incredible diversity of organisms. Apart from this, they are also the nurseries of many fishes on which humans depend for food. Corals in our country. Reefs are found in the eastern western coastal areas and in the Andaman and Nicobar Islands. Barrier type coral reefs are found in the Union Territory of Lakshadweep.

In modern times, the use of the word biodiversity has become widespread and it has started being applied to genes, species, community, ecological diversity etc. The origin of genetic diversity is necessary for the organism to adapt to the environment and survive, if due to any reason, the natural habitat of the living organisms gets destroyed, then the loss of their genes will harm the biodiversity. There will be a void in their adaptation, as a result, the balance of the entire ecosystem will become unstable, that is, there will be instability in the ecosystem. The less the genetic diversity among the organisms, the greater will be the overall  risk of their extinction because In such a situation, he will be completely unable to adapt himself to the environment.

Genetic diversity is visible in two forms as follows :
(i) In different populations of the same species. For example, the origin of different varieties of paddy.
(ii) Under the genetic variations of the same population. for example, the color, height, qualities, strength etc. of two children are never the same.
The specific genes present in the cells of each living organism are mainly responsible for the specific qualities. In other words, we can say that the greater the diversity of genes in an organism, the higher will be the number of specific characteristics in it and its future progeny. Thus, genetic diversity plays an important role in ethnic diversity.

There is a system of abiotic and biotic components in the ecosystem in which both of them interact with each other. Different types of organisms live in different ecosystems. For example, organisms of fresh water are different from the organisms of salt water. The greater the diversity in the habitat and niche of any particular organism, the greater will be the diversity in its ecosystem.
For example, there is extensive rainfall in a wide area of the tropical island, as a result the spread of the ecosystem is also greater there. e.g. Swamp (mangroves) ecosystems are found on the coast and submerged coral reefs near the coast. The more biodiversity there is in any ecosystem, the more stable it is. 

Social value of vegetation has been a part of human life since ancient times. Vegetation remains with humans on all the auspicious and inauspicious occasions that come in human life because man is a social animal and the diversity of life reflects social values in different forms.
Example : Banana, Tulsi, Peepal, Mango etc. are such plants which are an integral part of every religious ceremony organized in our homes. Mango, Ashoka are such trees whose leaves are compulsorily used during yagya, marriage and religious rituals. Undoubtedly, this type of mentality of human being preserves nature's botanical wealth.

Medicinal value of biodiversity : Biodiversity is a rich source of substances with therapeutic properties. Morphine obtained from Papever sominiferum is used as an analgesic, Quinine (Chincona sp.) is used for the treatment of Malaria, Taxol, anti-cancer drug obtained from the bark of Taxusbravifera, penicillin from Penicillium notatum and many other antibiotics used in treatment of different disease are obtained from many bacteria. Currently 25% of the medicinal drugs are drived from mere 120 species of plants.

Trait : Traits are responsible for keeping a particular species alive. These genes are representative of the respective species in any population.
Gene Pools : The process of joining together the genes of organisms of any population so that they can be preserved and used in the future is called gene pool.