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http://ptuas.loremate.com/evs/node/5 March 7, 2012

Environmental Science

Q. 1. Discuss threats to biodiversity.

Ans.Threats to biodiversity

1. Habitat loss. In order to utilize the resources, there occurs the destruction of habitat.

2. Disturbance and pollution. Large number of organisms are destroyed due to natural disturbancessuch as fire, tree fall, defoliation by insects. Mans activities are causing pollution.

3. Introduction of exotic species. Introduction of new species into an area cause disturbances whichmay lead to disappearance of native species.

4. Extinction of species is a natural process.

Q. 2 State biodiversity hot spot and on what basis a region is designated as hot spot?

Ans.Hot spots of biodiversity. The concept of Hot-spots was developed by Norman Myers (1988)to designate specific areas for in-situ conservation. The hot spots are the richest and mostthreatened reservoirs of plant and animal life on earth.

The criteria for determining hot spots are

1. Number of endemic species.

2. Degree of threat which is measured in terms of habitat loss.

There are 25 hot spots in the world out of which two are in India. They are Western Chats andEastern Himalayas.

Hot spot of Eastern Himalayas are active centres of evolution and rich in diversity

of flowering angiosperms. Western Chats have semi evergreen forests. Western Chats include twomain centres of biodiversity i.e. A qastyamalai hills and Silent valley.

Q. 3. What is the difference between Threatened species and Endangered species?

Ans Threatened Species. A threatened species is the one that is liable to become

extinct if not allowed to realise full biotic potential by providing protection from exotic species/humanexploitation/habitat deterioration/depletion of food.

Endangered Species (E). The species is facing danger of imminent extinction due

to:

(i) Reduction in habitat

(ii) Abundance of predator/pathogen/pollutant

(iii ) Very few in number

Examples : Blue Whale, Asiatic Wild Ass (Asinus hemionus Khur in Rann of Kutch), Lion TailedMacaque (in Dipterocarpus forests of South India). The number of Lion Tailed Macaque is only 195because of destruction of habitat, poaching for flesh and capturing.
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(i) Genetic diversity

(ii) Species diversity, and

(iii ) Community and ecosystem diversity.

These levels of biodiversity are interrelated, yet distinct enough to be studied separately tounderstand the interconnections that support life on earth.

(b) Genetic diversity. All living organisms store genetic information and functions according to theinformation coded in genes.

Genetic diversity refers to the variation of genes within species. The differences could be in alleles(different variants of same genes), in entire genes (the traits determining particular characteristics)or in chromosomal structures. The genetic diversity enables a population to adapt to its environmentand to respond to natural selection. If a species has more genetic diversity, it can adapt better to thechanged environmental conditions. Lower diversity in a species leads to uniformity, as the case withlarge monocultures of genetically similar crop plants. This has advantage when increased cropproduction is a consideration, but can be a problem when an insect or a fungal diseases attacks the

field and poses a threat to the whole crop.

Genes present in Mycoplasma1 E. coli, Drosophila, Oryza sativa and Homo sapiens

Q. 8. Explain what is meant byspecies diversity. Give theapproximate number of plant andanimal species recorded in India.

Ans.Species diversity. The diversityincludes the whole range of organismsfound on earth. The number of identifiedspecies world wide is between 1.7 and 1.8 million. However the estimates of total known speciesmay be 50 million. A large number of plant and animal species are yet to be identified. There aremany more species to be

present in the tropics.

Short Answer Type Questions

Q. 1. Explain the different types of biodiversity conservation techniques and their benefits.

Ans.Conservation of biodiversity.

(a)In situ Conservation

(b)

The in-situand ex-situapproaches ofconserving

biodiversity inIndia.

1. In situconservation is


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carried out throughBiospherereserves, Nationalparks

and wildsanctuaries and other protected area by Ministry of Environment

and Forest reserve,

2. The National Bureau of plants, animals and fish genetic resources collect,

conserve and store germplasms of plants and animals in seed gene banks or

field gene banks.

3. Botanical Gardens and Zoological Parks have large collection of plant and animal

species.

Advantages of in situ conservation

1. It aids in maintaining gene banks.

2. It is vital for Maintenance of species and check its extinction.

3. It helps in preservation of genetic variability.

4. It helps in preserving the quality of life for millions of forest dwellers.

5. In situ conservation helps to supply materials to restore plants.

Limitations of in situ conservation. The forests are being destroyed to make dams, reservoirs, andestablish industries. By doing this we are losing the wild plants which otherwise are so important forin situ conservation.

(b) Ex-situ conservation.

The need to conserve a species offsite (called ex-situ) arises when its population is so fragile orfragmented that its survival may no longer be possible in the wild; or that for reasons of distance,logistics or legality, its conservation in normal natural state may not be possible.

Advantages of ex situ conservation. 1. In such cases, representative samples of threatened orendangered species can be (and are being) successfully conserved and propagated in botanicaland zoological gardens, research centres, aquaria arid other such locations.

2. Ex-situ locations provide easy study sites and opportunities for raising public awareness onconservation issues.

3. The species show good signs of recovery and propagation in such places.

4. They can then be re-introduced back in the natural habitat.

Methods. For the conservation of genetic diversity, especially of plants, gene banks in the fields andthe laboratories and in vitro storage are some of the methods often used for ex-situ conservation.

(c) Sacred forests. These are forest patches protected by tribal communities in India and otherAsian countries due to religious belief. These are undisturbed forests having no human interventionand frequently surrounded by highly degraded landscapes. Such forests are located in many states


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of India and have a number of rare, endangered and endemic species. Likewise, Khecheopalriwhich contains several aquatic fauna and flora is declared as a sacred lake in Sikkim.

Q. 2. How did Green revolution affect diversity of food plants ?

Ans.Green Revolution. N.E. Barlavg and M.S. Swaminathan are pioneer of green revolution inIndia. It signifies increase in agricultural productivity resulting from the introduction of high yieldingvariety of grains, the use of pesticides and inproved management techniques. Just like the two

sides of coin the brighter side is that green revolution helped in increasing total food amount but onthe other side (i.e. darkside) affected the diversity of food plants in the following ways

1. It leads to extinction of traditional and more resistance variety.

2. It replaced mixture and rotation of crops like wheat, maize, millets, pulse and oil seeds withmonocultures of wheat and rice. Monoculture and dual cropping reduce the nutritional value of ourfood also.

3. The introduced crops like wheat and rice varieties came from a very narrow genetic base of thethousand of verities developed, only three were found to be suitable for green revolution. On this

narrow and alien genetic base the food supplies of millions was affected.

4. Because of their narrow genetic base.. High Yielding Varieties (HYV) are inherently vulnerable tomajor pests and diseases.

5. Large scale monoculture provide a large and permanent niche for pests turning minors diseaseinto epidemics; in addition, fertilizers have been found to lower pests resistance in plants.

6. The new High Yielding Varieties (HYVs) reduce the supply of fodder and organic fertilizers.

Q. 3. (a) List the three types of extinction processes.

(b) How is introduction of exotic species leading to endangering the species?

Ans.(a) Types of extinction processes

Natural extinction. With the change in environmental conditions, some species disappear andothers, which are more adapted to changed conditions, take their place. This loss of species whichoccurred in the geological past at a very slow rate is called natural or background extinction.

Mass extinction. There have been several periods in the earths geological history

when large number of species became extinct because of catastrophes. Mass extinctions occurred

in millions of years.

Anthropogeflic extinction. An increasing number of species is disappearing from the face of theearth due to human activities. This man-made mass extinction represenis a very severe depletion ofbiodiversity, particularly because it is occurring within a short period of time.

(b) Introduction of exotic species is endangering of species

Exotic species are having large impact especially in island ecosystem which harbour much of theworlds threatened biodiversity. A few examples are

(i) Nile perch, an exotic predatory fish introduced into Lake Victoria (South Africa) threatens theentire ecosystem of the lake by eliminating several native species of the small Cichlid fish speciesthat were endemic to this freshwater aquatic system.

(ii) Water hyacinth clogs rivers and lakes and threatens the survival of many aquatic species in


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lakes and river flood plains in several tropical countries including India.

(iii ) Lantana camara has invaded many forest lands in different parts of India, an

strongly competes with the native species.

Q. 4. Write a short note on three perspectives of community and ecosystem level ofdiversity.

Ans.The three perspectives of diversity at level of community and ecosystem are :

1. Alpha diversity 2. Beta diversity and 3. Gamma diversity.

1. Alpha diversity. It refers to diversity of organisms sharing the same community. It has been foundthat there is increase in diversity with decrease in latitude.

2. Beta diversity. The rate of replacement of species along a gradient of habitat or communities iscalled beta diversity.

3. Gamma diversity. It is rate at which additional species are found as replacement in different

localities of the same habitat.

Q. 5. Write short note on the Protected areas.

Ans.Protected areas. These areas of land or sea are dedicated to protection and maintenance ofbiological diversity. They include National Parks, Sanctuaries and Biosphere reserve.

As on Sept. 2002, India has 581 protected areas.

National parks. A national park is an area which is strictly reserved for the betterment of the wildlifeand where activities like forestry, grazing or cultivation are not permitted. In these parks, even

private ownership rights are not allowed.

Sanctuaries. A sanctuary is a protected area which is reserved for the conservation of only animalsand human activities like harvesting of timber, collection of minor forest products and privateownership is allowed so long as they do not interfere with well being of animals.

A biosphere reserve is a specified area in which multiple use of the land is permitted by dividing itinto certain zones, each zone being specified for a particular activity.

Benefits of protected areas.

1. Maintaining viable populations of all native species and subspecies.

2. Maintaining the number and distribution of communities and habitats, and conserving the genetkdiversity of all the present species.

3. Preventing human-caused introduction of alien species.

4. Making it possible for species/habitats to shift in response to changes in the environment.

Q. 6. What is biosphere reserve ? What are its zones? Explain role of biosphere reserve.List a few biosphere reserves.

Ans.Biosphere Reserve. A biosphere reserve is a specified protected area of land and or coastalenvironment in which multiple use of the land is permitted by dividing it into zones, each for aparticular activity.

Biosphere reserves are a special category of protected areas of land and/or coastal environments


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wherein people are an integral component of the system. These are representative examples ofnatural biomes and contain unique biological communities.

The zonation in a terrestrial Biosphere Reserve

Recently, the concept of Biosphere Reserves has been evolvedby UNESCOS Man and Biosphere Programme (MABP). Till May2002, there are 408 biosphere reserves located in 94 countrieSout of which 13 are in India. Of these, the Nilgiri BiosphereReserves was declared in 1986.

Zones of Biosphere Reserve. A biosphere reserve is divided intothree zones core, buffer and manipulation.

(i) Core Zone. No human activi is allowed in the core zone.

(ii) Buffer Zone. Limited human activity is permitted in the buffer zone.

(iii ) Manipulation Zone. Several human activities can occur in the manipulatiOn

zone.

Role of a Biosphere Reserve. A biosphere reserve preserves (a) Conservation of. wildpopulation(b) Development, and (c) genetic resources of domesticated plants

and animals carrying out scientific research, monitoring and education.

Biosphere reserves of India.

1. Nanda Devi 8. Nilgiri

2. Nokrek 9. Great Nicobar

3. Manas 10. Similipal

4. Dibru Saikhowa 11. Jchanghendzonga

5. Dehang Debang 12. Pachmarhi

6. Sunderbans 13. Agasthyamalai

7. Gulf of Mannar

Q. 7. Differentiate National Park, Wildlife Sanctuaries and Biosphere Reserve.

Ans.Differences between National Park, Wildlife Sanctuaries and Biosphere

Q. 8. (a) Whatis a wildlife?How does ithelp in

maintenanceof the


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environment?

(b) Give themain causesof extinctionof a speciesby humanintervention.

Ans.(a) Wildlife. The livingorganisms in itsnatural habitatis termedwildlife. Itincludes allplants, animalsand microorganisms other than cultivated plants and domesticated animals.

Role of wild life in the maintenance of environment. The wildlife is of great

value as it balances population and plays vital role in maintaining food chains and natural cycles.Thus it preserves the environment as self-sustaining system.

(b) Causes of extinction of a species by human intervention.

1. Man made forest fires have caused the extinction of several species in the past. With regard toIndia, in this century itself, of the mammals and birds the Indian Cheetah, Lesser Indian Rhino, thePink headed Duck, the Forest Owlet and the Himalayan Mountain Quail and 20 species of higherplants are reported to have become extinct

2. Habitats which protect wild life are being converted to human settlement harbours, dams,reservoirs, croplands, grazing grounds, plantation and mining

sites. Environmental pollution and deforestation have also resulted in the

degradation of important habitats.

3. The introduction of exotic species has affected many native species by imposing new factors incompetition for food and space, predation, habitat degradation

and destruction.

4. Over-exploitation such as over-fishing is another cause of extinction of wild life.

Q. 9. Why would it be unethical to destroy wild species?

Ans.It is an established fact that rich diversit of or anisms toda are the outcome of natural


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evolution stretching about 3.5 billion years. A species once lost cannot be retrieved. Therefore, itwould be unethical on the part of man to be responsible for destruction of a species. Man has anevolutionary responsibility to conserve biological diversity for our generations to come.

Q. 10. Discuss the role of wild life in modern agriculture.

Ans.Role of wild life in modern agriculture.

1. Maintenance of gene bank for breeding programme in agriculture.

2. To get high yield from crop plants is not with the simple application of pesticides and fertilizersand proper irrigation but the crop plants must have the genetic potentiality to respond to improvedinputs. Thus by examining wild relatives of crop plants useful genes can be selected and introducedto breeding programme e.g. Resistance gene has been successfully introduced to modern rice.

3. An average life of a crop variety is 515 years only. New varieties are being produced to meetthe changing conditions such as pathogens, pests climate and soil etc.

Q. 11. Write a short note on Project Tiger.

Ans.A conservation programme named Project Tiger was launched in 1973 for the purpose ofsaving tiger population from extinction in India. Management plans include the following aspects

(i) Elimination of all forms of human exploitation and disturbance from the core area andrationalisation of such activities in the buffer area; (ii) Limitation of the habitat management to repairdamage done by man with the aim of restoring the ecosystem as close to its natural functioning aspossible; and (iii) Researching facts about habitat and wild animals and carefully monitoringchanges in flora and fauna.

The number of Tigers in India in 1972 was reduced to 1200 from 40,000 in 1900. To

overcome this alarming state Project Tiger was launched with the help of World Wild

Life Fund. Nine tiger reserves in nine states with total area of 13017 sq. km were set

aside with a tiger population of 300. Today there are 11 reserves spread over 11 states.

Out of the total area, an area of 4935 km is set apart as a core zone. The core zone is free

from human interference. The population has increased to 3000. This process is still

going on.

Q. 12. What is zoo ? Write a note.

Ans.Zoo. Zoo is a place where wild animals are housed in captivity. Since everybody does not getan opportunity to go to the jungles to see the wild animals in their natural habitats, they satiate theirurge by visiting a zoo. The Zoo (Zoological Park) is also a place for education and recreation.Worldwide over 500 Zoos house about 540,000 individual animals many of them from species notthreatened or endangered. In India, there are 275 recognized Zoos, Deer Parks, Safari Parks,

Aquaria etc. in addition to a large number of mini-zoos.

Of late the Zoos have acquired a new role as centres for ex-situ conservation. Towards this end the

Government of India has set up a Central Zoo Authority for proper management of zoos. Central zooauthorities also co-ordinate the functioning of zoo.

Long Answer Type Questions

Q. 1. What is biodiversity ? Describe importance of biodiversity.


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Ans.Biodiversity. It refers to totality of genes species and ecosystem of a region. It is theoccurrence innumerable number of different types of organisms and the complete range of theirvarieties adapted to different climates, environments and areas. Biodiversity is the biological wealthof world.

Biodiversity as sources of food and improved varieties.

1. Use of biodiversity in agriculture:

(i) As a source of new crops.

(ii) As a source material for breeding varieties.

(iii) As a source of new biodegradable pesticides.

Only 20% of total plant species are cultivated to produce 85% of worlds food.

Wheat, corn and rice, the three major carbohydrate crops, yield nearly two third of the foodsustaining the human population. Fats, oils, fibres, etc. are other uses for which more and more new

species need to be investigated.

2. Ecological role of biodiversity

(i) Biodiveristy provides plant pollinators, predators, decomposers and contributed to soil fertility.

(ii) It helps in the purification of air and water, management of flood, drought and otherenvironmental disasters.

(iii ) Ecosystems with more diversity can withstand the environmental challenges better becausegenetically diverse species present in the ecosystem will have different tolerance ranges for a given

environmental stress, hence they cannot be easily eliminated by any single stress at a time.However, if the ecosystem contains only few species, it will become a fragile or unstableecosystem.

(iv) The species with high genetic diversity and the ecosystems with high biodiversity have greatercapacity for adaptation against environmental perturbations.

3. Drugs and Medicines from biodiversity. Several important pharmaceuticals we originated asplant-based substances. Examples of plant-derived substances eveloped into valuable drugs are :Morphine (Papaver somniferum), used as an analgesic; and Taxol, an anticancer drug obtainedfrom the bark of the yew tree (Taxus brevifolia, T. baccata). Currently, 25% of the drugs in the

pharmacy are derived from a mere 12 species of plants. But, throughout the world, traditionalmedicines make use of thousands of plant species. Plants can also be used for the manufacture ofinnumerable synthtic products, called botanochemicals.

4. Role of biodiversity in Industry.

(E) Wild plants, animals and their products are of great importance to industry as sources oftannins, resins, gums, oils, dyes, fragrance, perfumes, waxes, lubricants, hydrocarbons, rubber,latex, and other commercially useful compounds.

(ii) Some products of animal origin include wool, silk, fur, leather, waxes and lubricants.

(iii ) With the development of modern technologies the potential for new industrial products fromcurrently unknown or poorly known plant and animal species is immense.

5. Aesthetic and cultural benefits. Examples of aesthetic rewards include ecotourism, bird watching,


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wildlife, pet keeping, gardening, etc. Throughout human history, people have related biodiversity tothe very existence of human race through cultural and religious beliefs.

6. Biodiversity is essential for the maintenance and sustainable utilization of goods and servicesfrom ecological system as well as from individual species.

Q. 2. Discuss Indias Mega diverse biodiversity.

Ans.Indias Mega diverse biodiversity

Biodiversity : There is much diversity of flora and fauna in the oceans India has over 6000 km ofcoastline with an area of 20,13,410 km2. It harbours a great variety of marine biota including seaweeds, fish, crustaceans, amphibia, molluscs, corals, reptiles, mammals, etc.

India has 45,000 species of plants (15% of known world plants) and is an important primary centreof origin of about 167 important cultivated plant species like rice, sugarcane, jute, millets, cucurbits,legumes, mango, banana, Dioscoreas, turmeric, spices, many ornamental plants like orchids,medicinals and aromatics. India is also asecondary centre of maize, red pepper, soyabean andrubber plants.

There are 15,000 species of flowering plants, 35% of which are endemics and largely concentratedin Western Ghats, North-east and North-west Himalaya, and Andaman and Nicobar islands. About5000 plants species occur on Western Ghats of Kerala, 235 being endemic. North-east Indiacontains 675 orchid species (1000 in India and 17,000 in the World).

India has about 75,000 species of animals, 80% of which are insects. India has many endemicanimal species 53% fresh water fish, 60% amphibians, 36% reptiles and 10% of mammals.India has wide diversity in domestic animals like cows, buffaloes, sheep, goats, pigs, camels, yaks,horses, poultry etc.

Characteristics of Indias biodiversity. Biodiversity is not uniformly distributed

in space and time. It is rich in tropics. Indias biodiversity is characterised by the following

1. India contains 10 bio-geographic regions which include the Himalayan, TransHimalayan, theIndian desert, the Semi-arid zone, the Western-Ghats, the Deccan Peninsula, the Gangetic Plain,North-East India and the Islands and Coasts which possess different biodiversity levels.

2. India is one of the worlds 12 leading biodiversity centres of the origin of cultivated plants.

3. India has 5 natural world heritage sites, 14 biosphere reserves, 89 national parks, 492 wildlifesanctuaries and 2 hotspots. Heritage sites are the places

that attract tourists.

4. About 33 per cent of the countrys recorded flora are endemic to India and concentrated in theNorth-East, Western-Ghats, North-West Himalaya and

Andaman and Nicobar islands.

Q. 3. Define IUCN Red list. What are its uses 7 Give definition of different IUCN-Red listcategories.

Ans.IUCN Red List. It is a catalogue of taxa that are facing the risk of extinction.

IUCN has recognized eight red list categories of species. They are

(i) Extinct, (ii) Extinct in wild (iii) Critically endangered (iv) Endangered (v) Vulnerable (vi) Lower risk


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(vii) Data deficient and (viii) Not evaluated.

The 2000 red list contains assessment of more than 18,000 species, 11,000 of which

are threatened.

Uses of IUCN Red list categories.

The uses of the Red Lists are

(i) Developing awareness about the importance of threatened biodiversity;

(ii) Identification and documentation of endangered species

(iii) Providing a global index of the decline of biodiversity

(iv) Defining conservation priorities at the local level and guiding conservation action.

Q. 4. Whatare the mainreasons forextinction of

biodiversity?

Ans.Reasons

for Extinctionof Biodiversity

1. Habitat loss.The naturalhabitat may bedestroyed byman for hissettlements,grazinggrounds,agriculture,mining,industries,dam buildingetc. As aconsequenceof this, thespecies must adapt to the changes, move elsewhere or may succumb to predation, starvation ordisease, eventually dies. In India, several rare butterfly species are facing extinction with theuncannily swift habitat destruction of the Western Ghats.

2. Hunting. Man has always hunted the animals for its food, wild animals are hunted for theirproducts such as hide and skin, tusk, for meat, pharmaceuticals, perfumes, cosmetics, decorationpurposes.

In our country, rhinoceros is hunted for its horns, tiger for bones and skin, musk


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deer for musk, elephant for ivory etc. One of the most published commercial hunts is that of whale.

3. Over exploitation. This is one of the main causes of the loss of not only economic species butalso biological curiosities like the insectivorous, primitive species and other taxa needed forteaching of lab work. Commercial exploitation of wild plants has invariably meant its overuse,eventual destruction.

4. Collection for zoo and research. Animals and plants are collected throughout the world for zoo

and biological lab for study and research in science and medicines.

5. Introduction of exotic species. Native species are subjected to competition for food and spacedue to introduction of exotic species. For example, introduction of goats and rabbits in the Pacificand Indian regions has resulted in destruction of habitats of several plants, birds and reptiles.

6. Control of pest and predators. Predators and pest control measures, generally kill predators thatare a component of balanced ecosystem and may also indiscriminately poison non target species.

7. Pollution. Pollution alters the natural habitat. Water pollution especially injurious to the bioticcomponents of estuary and coastal ecosystem. Toxic wactes entering the water bodies disturb the

food chain and so to the aquatic ecosystems. Insecticides, pesticides sulphur dioxide, nitrogenoxides, acid rain, ozone depletion and global warming too, affect adversely the plant and animalspecies.

The impact of coastal pollution is also very important it is seen that coral reefs are being threatenedby pollution from industrialization along the coast, oi l transport and offshore mining. Noise pollutionis also the cause of wildlife extinction.

8. Deforestation. One of the main causes for the loss of wild life is population explosion andresultant deforestation. Deforestation mainly results from population settlement, shifting cultivation,development projects, demand for fuel wood, demand of wood as a raw material for many

industries such as paper and pulp, match, veneer and plywood, furniture etc.

9. Other factors. Other ecological factors that may also contribute to the extinction of wildlife are asfollows

(i) Distribution range. The smaller the range of distribution, the greater the threat of extinction.

(ii) Degree of specialization. The more specialized an organism is, the more vulnerable it is toextinction.

(iii )Substitution. During the process of evolution an existing species may be replaced by ecological

another one.

(iv) Position of the organism in the food chain. The higher the position of the organism is in foodchain, the more susceptible it becomes.

(v) Reproduction rate. Large organisms tend to produce fewer offspring at widely spaced intervals.

(vi) Outbreak of diseases. It is also one of the major causes for the decline in wildlife species.

(vii) Loss of gene flow. The individuals of plant and animal life may decline to significant level asaresult of loss of gene flow.

Q. 5. What is biogeographical classification of India?

Ans.Biogeographic Classification of India

Biogeographical Regions: India is one of the 12 megadiversity countries of the World with about


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120,000 identified species of plants and animals. The Indian territory (80_300 N and 600_97.50E)with a total area of 329 million hectares having large variety of ecological habitats like HighHimalayas, warm coast of Peninsular India, humid tropical Western Ghats, hot desert of Rajasthan,cold desert of Ladakh etc. There are 10 biogeographical regions of India

1. TransHimalaYa, 2 Himalaya, 3. Desert, 4. Semi-arid, 5. Western Ghats,

6. Deccan Peninsula, 7. Gangetic Plain, 8. Coasts, 9. North East, 10. Islands.

Biogeographical regions of India

Q. 6. Extinction is the ultimatefate of all species ? Why thenwe are concerned about declineof biodiversity

Ans.Extinction or the elimination ofa species, is a normal process innature. Species die, and are

replaced by other, generally by theirown descendants, as part ofevolutionary change. The rate ofextinction in undisturbed ecosystemis estimated to be high in the lastmany decades. Human impact inthe populations ecosystems haveaccelerated that rate, causinghundreds of species, subspeciesand varieties to become extinctevery year and if the present trend

continue, millions of kinds of plants,animals and micro organisms maybe destroyed in the next fewdecades.

Classification of extinctionprocesses.

1. Natural extinction. It is due to change in environmental condition. It is a very slow rate.

2 Mass extinction. Mass extinction occurs due to catastrophes. In this case, large number of

species became extinct in millions of years.

3. Anthropogeflic extinction. Extinction of species due to mans activities. It is occurring in a shortperiod of time.

Consequences of extinction of species.

1. Climate change. Climate change simply bring shift in distribution of species (which is largelydetermined by climate).

2. Natural catastrophe. Means a sudden change in the environment brought by nature. it includes

fire, storm, floods, earthquakes etc.

3. Pollution. Pollution leads to changes in natural habitat. Toxic pollutants can have disastrouseffects on local populations of organisms.

Example : DDT, PCB, dioxins etc.


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4. Diseases. The incidence of diseases in wild species may increase due to human activities. Theextent of diseases increases further when animals kept in captivity. Animals as compared to plants,are more prone to infections when they are under stress.

Q. 7. India is a country of biodiversity. Comment on the statement.

Ans.India has a rich heritage of biodiversity as it is rich in all three types of biodiversity geneticspecies and ecosystem. A wide range of diverse habitats starting from tropical rain forests to

Alpine region and temperate forest to coastal land make this country a rich source of biodiversity

India is one of the twelve mega diversity nations of the world, 7.31% of the global fauna and 10.88%of global floral species.

Some Interesting features of Indian Biodiversity are:

(i) In India about 1,15,000 species of plants and animals have been identified.

(ii) Many crops like rice, sugarcane mango originated in India and spread throughout the world.

(iii ) In flora, India has 45,000 species which account for about 15 percent of known world plants.

(iv) India has about 75,000 animal species, about 80 percent of which are insects.

(v) India has 10 biogeographical regions.

Q. 8. Write a detailed note on Biogeographical regions of India.

Ans.The Department of forest and wildlife has divided India into 10 biogeographical areas keepingin mind animal species biodiversity.

1. Trans Himalayas. Ladakh (1 & K) and Lahol Spiti (Himachal Pradesh). This area is situated at anaverage of height of 4500 to 6000 m from sea level. The area of this region is 1,86,200 sq. km.Here Tibeti donkey, wild yak etc. are found.

2. Himalaya (North, West, Central & East). About 2,36,300 sq. km area situated at different heightsin Himalayas comes in this category. In these areas there is diversity in species and habitat arefound. Here 56 areas are protected areas. In these areas, there are more endangered species thanin other areas of India.

3. Desert (KachChh_GUjat Thar_RajaSthan). This area is spread up in 2,50,100 sq. km. This areais delicate ecological system. Here only 89 sq. km area is protected area. Here wild ass, desert

cat, desert fox etc. are found.

4. Semi Arid Area (Punjab, Gujarat and Rajasthan). This area is spread over 5,08,000 sq. km. Theleopards of this area are conserved in sariska and Ranthambor National Park. Here 52 protectedareas are spread in 11,675 sq. km. Gir lioi is its special species.

5. Western Ghat, Coastal Plain and Hills of Maharashtra, Kerala & Karnatka. This area is spreadover 1500 sq. metre long hill chain from evergreen forests to dry deciduous forests. Here about1,800 special local species are found. Here 44 protected areas are spread over 15,955 sq. km.

6. Deccan Peninsula, Deccan Plateau, Southern Central Plateau, North-Eastern Plateau,

ChhotaNagpur, Central High lands. This area is spread over 14,21,000 sq. km and has 115protected areas spread over 4610 sq. km. The 43% of whole earth part is Deccan island.

7. Gangetic plain/ Plains of Ganga (Upper & lower plains of Ganga). It is spread over 3,59,400 sq.km area which has 25 protected areas. Because cultivation is done in this area from centuries, rarewild animals are found here.


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8. Sea Coast (Western and Eastern Coast). Biological rich lash vegetation is found here. In it seaand eustary both type of plants and animals are found. Sunderban Sanctuary has many moreleopards than in any other area.

9. Northern Eastern Area (Brahamputra Valley, Hills of Assam). Here biological rich sources ofvaried diversity of plants and animals are found. It has 17 protected areas spread over 1880 sq. km.

10. Indian Island Group (Andaman, Nicobar and Lakshdeep Island). This is a group of 348 islands

rich in biodiversity. It has 225 species of animals in which 112 are special areas. It has 100protected areas spread over 708 sq. km.

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