Sunday, 6 July 2014

GE2021 - Environmental Science and Engineering Two Mark With Answers

GE2021 - Environmental Science and Engineering Two Mark With Answers

UNIT – I Environment, Ecosystems and Biodiversity

1. Define Environment?

The sum of total of all living and non living things around influencing one another is known as environment.

2. Explain biosphere.

The part of lithosphere, hydrosphere and atmosphere at which living organisms interact with each other.

3. Environmental awareness is of the hour comment.

a. To create awareness among people about environmental issues.

b. To minimize the utilization of natural resources.

c. Need of alternate energy resources.

d. Implementation of environmental protection act.

4.What is ecology?

Ecology (from the Greek word “oikos” “house” or place to live and logos “study of”) is the study of how organisms interact with one another and with their non living environment.

5.Define ecosystem?

An ecosystem is a community of different species interacting with one another and with their non living environment of matter and energy

6.What are the two components of an ecosystem?

1. Abiotic – nonliving chemical and physical component such as water, air, nutrients in the soil or water and solar energy.

2. Biotic – consist of living and dead plants, animals and micro organisms.

7.What are producers (autotrophs)?

Producers (autotrophs) make their own food from the compounds that are obtained from their environment. Most producers capture sunlight to make carbohydrate by photosynthesis.

6CO2 + 6 H2O+ solar energy → C6H12O6 + 6O2

8.What is the role of decomposer?

Decomposers are specialized consumers that recycle organic matter in ecosystem. They do this by breaking down dead organic material to get nutrients and releasing the resulting simpler inorganic compounds into soil and water, where they can be taken up as nutrient by producers.

9.Define food chain & food web?

The sequence of eating and being eaten in an ecosystem is known as food chain. It determines how energy and nutrients move from one organism to another through an ecosystem.

Food web is a net work of food chain where different types of organisms are connected at different tropic level, so that there are a number of options of eating and being eaten at each tropic level tropic level.

10.What is ecological pyramid?

A graphical representation of trophic structure and function of an ecosystem starting with producers at the base and successive trophic levels forming the apex is known as ecological pyramid.

11.Define biodiversity?

Biodiversity means the variability among living organisms from all sources including interracial, terrestrial, marine and other aquatic ecosystem and the ecological complexes of which they are part, this includes diversity within spices, between species and ecosystem.

12.What are hot spots of biodiversity?

Hot spots are areas that are extremely rich in species, have high endemism, and are under constant threat. Among 25 hot spots, 2 are found in India extending into neighboring countries

Ø The Western Ghats/ Srilanka and

Ø Indo- Burma region (covering eastern Himalayas)

13.What is red data book?

The red data book is the name given to the book dealing with threatened animals or plants of any region.

14.Define the terms, endangered, vulnerable, rare, threatened, and endemic?

Endangered: Taxa in danger of extinction and where survival is unlikely if the casual factors continues to operate.

Vulnerable: Taxa believed likely to move into the endangered category in the future, if

the casual factors continue operating.

Rare: Taxa with small world population but that are not at presently endangered or

vulnerable, but are at risk.

Threatened: It is a general term to denote that are fall into any of the above category

(endangered vulnerable & rare).

Endemic: Taxa which are native or restricted to a particular region.


1. Explain the scope and objective of environmental studies?


The scope and objective of environment studies is “to cultivate our public to be aware and concerned about total environment and its associated problems and commitment to work individually and collectively towards solutions of current problems and the prevention of new ones.


· This study creates awareness among the people to know about various renewable and non renewable resources.

· It provides the knowledge about ecological systems, causes, and relationships between the components.

· To get an awareness.
Acquiring basic understanding of total environment problems.
To motivate in active participation in environment protection and improvement.
Developing skills to identify and solve environmental related problems.
Ability to evaluate environmental programmes.
This study helps to develop a sense of responsibility and urgency.
To help the public know the real causes of environmental problems and contribute towards solving them.
To focus on plans for growth and development through environmental aspects.
An environmental study is a long process of learning and it makes the man a more responsible citizen.


v One can understand how attitudes and values can affect the environment at present and as well as in the future.

v Environmental studies have a direct relation to the quality of life we live.

v Environmental studies relates to our surroundings which we observe daily but never think seriously.

v It implies getting right attitudes and values suitable to environmental protection.

v By teaching environment studies the people will understand the concept of need of development without causing destruction to environment.

v Environmental studies develop a concern and respect for the environment

v It informs people as to how they can play an effective role in protecting the environment by demanding changes in laws and enforcement systems.

2. Why public awareness is needed for environmental protection?


· Individual school, colleges, industries service centers, village, urban centers, etc, .should realize the importance of day to environmental issues.

· There is a need to meet the people and discuss again and again, so that problem is alive till it is eliminated.

· The government (central and states) have instituted awards for individuals and organizations for their services to environment management.

· Several universities and colleges have started environmental sciences/ environmental studies departments. They conduct courses and research works related to local and regional environmental issues.
Public participation is possible only when the public is aware about the ecological and environmental issues.
The public participation is useful in law making process and controlling the pollution activities
Thus, the public participation plays a major role in the effective environmental management
Environment is wrongly taken as “fashion” hardly realizing that it is our real life situation and our sustenance and security are at stake.
Few have clean ideas about what needs to be done.
Environmental awareness campaigns exploited politically

Protect the atmosphere
Protect the land resources.
Conserve the biological diversity
Prevent illegal movement of toxic product & wastes.
Check Environmental degradation.

3.Explain the structure and function of an ecosystem.

Structure and Function of an ecosystem:-

The two major aspects of an ecosystem are the structure and function.

By structure we mean

i) The composition of Biological community including species, numbers, biomass, life history and distribution in space.

ii) The quantity and distribution of non-living materials such as nutrients, water etc.

iii) The range or gradient of conditions of existence such as temperature, light etc.

By Function we mean

i) The rate of Biological energy flow.

ii) The rate of materials or nutrient cycle

iii) Biological or ecological regulation (including both regulation of organisms by environment and regulation of environment by organisms.

Thus in any ecosystem, structure and function are studied together.

Ecosystem concepts and components

Earth consists of large masses of land and vast expanse of oceans. Biologists classified terrestrial portion of the biosphere into biomes. They are large regions such as forests, deserts, and grasslands characterized by a distinct climate and specific life forms adapted to it.

Climate is the long term patterns of weather. It is the main factor determining what type of life, especially what plants will thrive in a given land area.

Each biome consists of a patch work of many different ecosystems whose communities have adapted to differences in climate, soil and other factors through the biome.

Marine and fresh water portions of biosphere can be divided into aquatic life zones each containing numerous ecosystems.

Freshwater life zones – lakes, ponds, streams, rivers

Ocean life zone – estuaries, coastal lines, coral reef & deep oceans.

4.Explain the energy flow of an ecosystem with a neat flow chat.

Energy flow in an ecosystem

Each trophic level in a food chain or web contains a certain amount of biomass, the dry weight of all organic matter contained in its organisms.

In a food chain or web, the chemical energy stored in Biomass is transferred from one trophic level to another.


5.Explain the following terms

a) Ecological succession

b) Food chain

c) Food web

d) Ecological pyramid.

a) Ecological succession

One characteristic of all communities and ecosystems is that their structures change constantly in response to changing environmental conditions. The gradual change in species composition of a given area is called Ecological succession.

During succession some species colonize on area and their populations become more numerous, whereas populations of other species decline and may even disappear.

Ecologistrecognize two types of Ecological succession, depending on the conditions present at the beginning of the process.

Primary succession - This involves the gradual establishment of biotic communities on nearly lifeless ground.

Secondary succession - which involves the establishment of biotic communities in an area where some type of biotic community is already present.

b&c) Food chain & Food web

The sequence of eating and being eaten in an ecosystem is known as food chain. It determines how energy and nutrient move from one organism to another through an ecosystem.

Ecologists assign each organism in an ecosystem to a feeding level or trophiclevel, depending on whether it is a producer or a consumer and on what it eats or decomposes.

Producers belong to first trophic level, primary consumers to the second trophic level and secondary consumers to the third and so on.

d) Ecological pyramids

Graphical representation of trophic structure & function of an ecosystem starting with producers at the base and successive trophic levels forming the apex is known as ecological pyramid. It is of three types.

Pyramid of numbers.

Pyramid of Biomass.

Pyramid of Energy.

6.What are the Kinds of Biodiversity?

It can be divided into three hierarchical categories-genes, species, and living systems and which scientists measure in different ways. Biodiversity is usually described at three levels.
Genetic diversity

Variations among the genes of the same species are known as genetic diversity.
Species Diversity

Diversity which arises due to variations among species present in specific areas is called species diversity.
Ecosystem Diversity.

Ecosystem Diversity is, therefore, the diversity of habitats which include the different life forms within. The term also refers to the variety of eco-systems found within a bio-geographical political boundary.

Diversity at the community level has three perspectives:-

a) Alpha Diversity (Intra community Diversity) is the diversity of organisms sharing the same habitat.

b) Beta Diversity (Inter community diversity) is the rate of replacement of species along a gradient of habitats

c) Gamma diversity is the diversity of habitats over a geographical area.

7.Explain the Biogeographical Classification of India.

India is considered a biodiversity-rich nation. For botanical and geographical purposes, the Indian subcontinent can be divided into many regions. Biogeography is the study of patterns of distribution of organisms in space and time.

Physically the country is divided into four relatively well defined regions.

1. The Himalayan mountains

2. The Gangetic river plains

3. The southern (Deccan) plateau

4. The islands of Lakshadweep, Andaman and Nicobar

These regions are discussed in detail below.

The Himalayan Mountains in the far north include some of the highest peaks in the world. The highest mountain in the Indian Himalayas is Kangchenjunga (8586m) which is located in Sikkim on the border with Nepal. To the south of the main Himalayan massif lie the Lesser Himalayas, rising to 3600-4000m, and are represented by Pir Panjal in Kashmir and Dhaula Dhar in Himachal Pradesh. Further south, flanking the Indo-Gangetic Plain, are the Siwaliks which rise to 900 – 1,500 m.

The northern plains of India stretch from Assam in the east to Punjab in the west (a distance of 2,400 km), extending south to terminate in the saline swamplands of the Rann of Kachchh (Kutch), in the state of Gujarat. Some of the largest rivers in India, including Ganga (Ganges), Ghaghara, Brahmaputra, and Yamuna, flow across this region. The plains are remarkably homogenous topographically: for hundreds of kilometers the only perceptible relief if formed by floodplain bluffs, minor natural levees and hollows known as ‘spill patterns’ and the belts of ravines formed by gully erosion along some of the larger rivers.

The Andaman and Nicobar islands comprise several small and large islands situated near the equator. This region has a wide range of forests from coastal vegetation to evergreen forests.

Zoogeographical regions of India



Himalayan region

The wild life wealth here consist of Yak, Gural, snow – leopard, kasturi deer Etc.

Malabar region

The climate here is moderate. VariousKinds of Monkeys, deer, etc. are foundhere

Nilgiri region

This region is extremely rich in Varieties of birds. Elephants are also Found here. Lions are found very rarely

Northern plains

The animals found in this region are elephants, leopards, Neelgai, jackal,deer, etc.

Desert land

Deer, cheetal, sambhar, neelgai, Snakes, lizards, etc. are abundantly found in this area.

Deccan plateau

Animals mainly found in this region are Elephants, lions, tigers, monkeys, deer and Some varieties of snakes.

Habitats of India

Depending of the climatic and physical conditions, Indian habitats can be classified into wetland, forest, and marine habitats.


India has a rich variety of wetland habitats. The total area of wetlands (excluding rivers) in India is 58,286,000 ha, or 18.4% of the country’s total area, 70% which comprises of areas under paddy cultivation. Two sites – Chilka lake (Orissa) and Kaeoladeo National Park (Bharatpur) – have been designated under the Convention of Wetlands of International Importance (Ramsar Convention) as being especially significant waterfowl habitats.


India possesses a distinct identity because of the great diversity of its natural ecosystems. The panorama of Indian forests ranges from evergreen tropical rain forests in the Andaman and Nicobar Islands, the Western Ghats, and the North Eastern states, to dry alpine scrubs high in the Himalayas to the north. Between the two extremes, the country has semi-evergreen rain forests, deciduous monsoon forests, and thorn forests, subtropical pine forests in the lower mountain zones and temperate mountain forests. Sixteen major forests types are recognized, subdivided into 221 minor types.

Marine Environment

The coastal waters of India are extremely rich fishing grounds. Coral reefs occur along a few sections of the mainland, principally the Gulf of Kutch, off the southern mainland coast, and around a number of Islands opposite Sri Lanka. This general absence is due largely to the presence of major river systems and the sedimentary regime on the continental shelf. Elsewhere, corals are also found in Andaman Nicobar and Lakshadweep Island groups although their diversity is reported to be lower than in south-east India.

8.What are the various values of Biodiversity?

i) Survival

Without biological diversity, we would perish. Biodiversity meets the basic survival needs of a vast number of people. In most communities the livelihood of the people revolves around the biodiversity of the area. For instance, in the forest belt of Ghana most men are hunters. These hunters survive on the availability of antelopes, rabbits, snails, etc.

ii) Health and healing

Even today, a large number traditional communities depend on traditional medicine for primary health care, most of which are derived from plants and animals. Approximately 25% of all prescription drugs are derived from plants.

iii) Food Security

Biodiversity is critical for agriculture. All our food is derived from the biological world. Wheat, potatoes, vegetables, fruits, milk, meat, honey etc are the outcomes of Biodiversity. Many plants species such as asafetida, ginger, mint, turmeric etc are used as spices all over the world. Biodiversity is also a source of new crops of improved variety and of bio-degradable pesticides.

iv) Productive Value

Biodiversity also has a productive value. There are many products used by human which are derived from natural sources. Cinchona plant is used to make medicines, and wood is used as fuel. Production of charcoal is through plants and trees. A number of dyes and dye based products are also obtained from plants.

v) Ethical Value

Each species is unique and has the rights to exist. Human do not have the right to eliminate any species. Scientific and ethical principle should guide developmental activities. Ethical use of natural elements has deep roots within human culture, religion, and society. A sustainable world requires an ethics that is ultimately incorporated into culture and is long lasting.

vi) Aesthetic pleasure

Biodiversity also has great aesthetic value. Each species and ecosystem adds to the richness and beauty of life on earth. Perhaps no medium can match the sheer joy of watching a sunset over an ocean, the sight of a leaping deer, the sounds of singing bird, or the smell of wet earth after the first rains. Other examples of aesthetic rewards include eco-tourism, Ornithology, wild life, keeping pets, gardening etc.

vii) Ecological Services

Species evolve to fill particular niches in an ecosystem or habitat. Many species also depend on each other in intricate ways of survival. Destroying one species can lead to further extinction or changes. Specific life forms present in a particular habitat help to create conditions for other life forms to live. For example, a single tree provides not only it’s products, which may have economic value, but it is also a habitat for innumerable living things. In addition, it also plays a vital role in conserving soil and water and helping to keep the air clean, nutrient cycling and climate regulation. In one study, published in 1997, in the science journal Nature, researchers estimated the value of these ecosystem services at between $ 16 Trillion and $ 54 Trillion a year.

9.Explain the Biodiversity at Global Level, National Level and local level.

i)Global Level

It is estimated that there exists 5-30 million species of living forms on our earth. Of these, only 1.5 million have been identified. These include 300,000 species of green plants and fungi, 800,000 species of insects, 40,000 species of vertebrates, and 360,000 of microorganisms.

According to some recent estimates; the number of insects alone may be as high as 10 million, but many believe it is more likely to be around 5 million.

The tropical forests are regarded as the richest in biodiversity. Scientists are of the opinion that whatever be the absolute number, more than half of the species on the earth live in moist tropical forests which is only 7% of the total land surface. Insects (80%) and primates (90%) make up most of the species. For instance, from a single tropical leguminous tree 43 ant species belonging to 26 genera have been retrieved. This approximately equals the ant diversity of all the British Isles. In 10 selected one hectare plots in Kalimanathan in Indonesia, Peter S.Aston of the Harvard University found more than 700 species, are almost equal to the number of tree species native to all of North America.

The following explanations have been put forward with regard to the high species diversity in tropics:

1. In tropics, conditions for evolution were optimum and for extinction fewer;

2. In tropics, species diversity was conserved over geological time. This is because low rates of extinction prevailing there; and

3. Biological diversity is the result of interaction between climate, organisms, topography, parent soil materials, time and the heredity. The tropics are the ideal place for such an interaction.

ii)Biodiversity at Country Level

The Indian region geographical area of 329 million hectares is quite rich in biodiversity with a sizable percentage of endemic flora and fauna. This richness in biodiversity is due to immense variety of climatic and altitudinal conditions coupled with varied ecological habitats. These vary from the humid tropical Western Ghats to the hot desert of Rajasthan from the cold desert of Ladakh and the icy mountain of Himalayas to the warm costs of peninsular India.

The country has over 115,000 species of plants and animals already identified and described. In addition, the country is very important Vavilovian Center of biodiversity and origin of over 167 important cultivated plant species, and some domesticated animals.

In fact, our country has been recognizing as one of the world’s top 12 mega diversity nations.

In flora, the country can boast of 45,000 species which accounts for 15 percent of the known world plants.

Of the 15,000 species of flowering plants, 35 percent are endemic and located in 26 endemic centers. Among the monocotyledons, out of 588 genera occurring in the country, 22 are strictly endemic.

The family Poaceae has the highest endemism both by genera and species.

The North Eastern region could boast of being unique treasure house of orchids in the country, the abode of about 675 species out of 1,000 available in the Indian peninsula and against 17,000 species the world over. The important Indian orchids are: Paphiopedilum fairieyamum (Lindl) pfitz., Cymbidium aloiflium Sw., Aerides crispum Lindl., etc.

Our country is very rich in faunal wealth also. The country has nearly 75,000 animal species, about 80 percent of which are insects.

In animals, the rate of endemism in reptiles is 33% and in amphibians 62%. Further there is wide diversity in domestic animals, such as buffaloes, goats, sheep, pigs, poultry, horses, camels and yaks. Domesticated animals too have come from the same cradles of civilization as the major crops.

There are no clear estimates about the marine biota though the coastline is 7,000 km long with a shelf zone of 452,460 sq km and extended economic zone of 20,13,410 sq km. There is an abundance of seaweeds, fish, crustaceans, mollusks, corals, reptiles and mammals.

Information regarding other flora and fauna are patchy. Hundreds of new species may be present in our country-awaiting discovery. The Western Ghats in Peninsular India, which extend in the southern states, are a treasure house of species diversity. Out of the described 15,000 species of the flowering plants in India about 5,000 species occur on the Western Ghats of Kerala; 235 are exclusive to this region. It is estimated that almost one-third of the animal varieties found in India have taken refuge in Western Ghats of Kerala alone.

iii)Biodiversity at local level (Tamil Nadu)

One sixth of landmass of Tamil Nadu is covered with forests. According to State of forest report 2003 by the Forest Survey of India, the total forest cover of the State is 22643 KM² constituting 17.41% of geographic area. This includes 2440 KM² of very dense forest, 9567 KM² of moderately dense forest and 10636 KM² of open forest. Tamil Nadu ranks 11th among the Indian States and Union Territories with reference to total forest cover. The recorded forest area of the state is 22,877 KM² constituting 17.59% of the geographic area. Tamil Nadu ranks 13th among the Indian States and Union Territories with reference to total recorded forest area.

There are 8 wildlife sanctuaries over 2, 82,685.57 ha and 12 bird sanctuaries over 17,074.59 ha, 5 National Parks over 30784.23 ha, 3 Tiger Reserves, 4 Elephant Reserves and 3 Biosphere Reserves for in situ conservation of wild fauna and flora.

The Angiosperm diversity of India includes 17,672 species. With 5640 species, Tamil Nadu ranks 1st among all the States in the Country. This includes 533 endemic species, 230 red-listed species, 1559 species of medicinal plants and 260 species of wild relatives of cultivated plant. The Gymnosperm diversity of the country is 64 species of which Tamil Nadu has 4 species of indigenous Gymnosperms. The Pteridophytes diversity of India includes 1022 species of which Tamil Nadu has about 184 species. Tamil Nadu wild plant diversity also includes vast number of Bryophytes, Lichens, Fungi, Algae and Bacteria.

The faunal diversity of Tamil Nadu includes 165 species of fresh water Pisces, 76 species of Amphibians, 177 species of reptiles, 454 species of birds and 187 species of mammals. According to the CAMP reports the red-listed species include 126 species of Pisces, 56 species of Amphibians, 77 species of reptiles, 32 species of birds and 40 species of mammals. The endemic fauna includes 36 species of Amphibians, 63 species of reptiles, 17 species of birds and 24 species of mammals

10.Write a detailed note on India as a Mega diversity Nation

The mega diverse countries are a group of countries that harbor the majority of the earth species and are therefore considered extremely bio diverse.

World Conservation Monitoring Centre identified the 17 mega diversity countries are: Australia, Brazil, China, Colombia, Democratic Republic of the Congo, Ecuador, India, Indonesia, Madagascar, Malaysia, Mexico, Papua, New Guinea, Peru, Philippines, South Africa, United States and Venezuela.

India is one the megadiverse nation of Asia. It is highly diverse having all the natural resources required for all kinds of living organisms. In addition to the vast diversity of plants and animals, our country is rich in cultural, geographical, and climatic diversity. The diversity in India is as follows;

· Geographical diversity: India is a vast geographic region. It comprises of Himalayan region, Ganga plains, Thar Desert, and Deccan plateau. The land form includes the plain of Ganga on one side to highlands of Deccan plateau on other side. Thus India represent almost all kinds of geographic variations found else where in the world.

· Climatic diversity: The climatic conditions of the country range from cold temperate and frost covered regions of Himalayas to low rainfall regions of the dry tropics in the north west of the country. On the basis of annual rainfall, the country can be divided in to four climatic regions-wet zone(more than 200cm),intermediate zone(100-200)cm, dry zone (50-100cm) and arid zone(below 50cm).Hence India has almost all climatic variations found else where in the world.

· Biodiversity: From the point of view of biodiversity, India is divided into nine phytogeographical regions. A variety of physical and climatic factors lead to the richness in biodiversity. The country is also one of the12 primary centers of origin of cultivated plants and domesticated animals. It is considered to be homeland of the167 important plant species of cereals, millets, fruits, condiments, vegetables, pulses, fibre, crop and oilseeds, and 114 breeds of domesticated animals. The country is also rich in animal biodiversity along with its rich plant biodiversity resources.

· Habitat diversity: India represents almost all types of habitats of the world. High mountains ranges, hills, plateau, plains, deserts, etc. provide a variety of habitats for plants and animals. Similarly a number of fresh water and saline lakes, reservoirs, ponds, rivers, streams provide diversity of habitats for aquatic plants and animals

· Cultural diversity: India is a country with a developed ancient cultivation. India’s culture has been enriched by successive waves of migration which where absorbed in to Indian way of life. Our country possesses vast cultural diversity; from Jammu and Kashmir in the north to Kanyakumari in the south; from West Bengal in the east to Thar Desert in the West. Rajasthan and Madhaya Pradesh represent a wide array of tribal cultures. Diversity can also be seen in food habits. Both vegetarian and non vegetarian food habits are common. Languages spoken in India have also created diverse traditions of culture in India. There are a large number of languages in India.Thus the country is rich in cultural diversity as well.

11.Explain the Hot Spots Of Biodiversity.

The hotspot concept has been designed by Norman Myres in 1988 to designate priority areas for in situ conservation. Hotspots are the richest and most threatened reservoirs of plant and animal life on earth.

Criteria for determination of a hotspot:

· Number of endemic species

· Degree of threat; in terms of habitat loss

Hotspots are areas of exceptionally rich concentration of species with high endemism but at the same time face high pressure of anthropogenic disturbances. There are 25 such hotspots all over the world. Out of 25 two hotspots are located in India. The first hotspot in India is the Western Ghats and second is the hilly region of north east Himalayas up to Myanmar in the east.

Endangered And Endemic Species.

At present the population of all plants and animals are declining rapidly and numbers of species are already on the verge of extinction. Such plants and animals species are called endangered species. The world conservation union has recognized eight red list categories of species; extinct; extinct in the wild; critically endangered; endangered; vulnerable; lower risk; data deficient and not Evaluated. The red data book, published in two volumes, lists about 25,000 endangered species from across the world. Flying squirrel, Gir lion, crocodile, flamingo,wild ass, etc. are some endangered animal species of India. Commiphora weightii(guggal), Ravolfia serpentine (sarpgandha), Santalum album (sandal), Adansonia digitata(kalpvrisha),Tecomella undulata(rohida),etc are some of the endangered plant species of India.

The plant or animal species confined to a particular region and having originated there or species which occur continuously in that area are known as endemism. Eletaria repens, ficus religiosa, butea monosperma,ficus benagalensis,etc some of the endemic plants of India.

12.What are the threats to Biodiversity?

1. Unplanned development and habitat destruction

When people cut down trees, fill a wetland, plough grasslands or burn a forest, the natural habitat of a species is changed or destroyed. Large scale development projects such as industrial plants or hydroelectric projects have contributed substantially to the loss of biodiversity rich areas. Projects such as construction of large dams not only result in submergence of large tracts of forests but also introduce human settlements and roads within forest areas.

2. Poaching and overexploitation for commercial gain:

Many plants and animals have been over exploited by humans, sometimes to the point of extinction. Many species such as tigers and elephants are killed or poached for their skin, tusks, claws, etc. which have high commercial value. Others, such as several snake and bird species are caught and smuggled out for their value for collectors and as pets. A rapidly expanding pharmaceutical industry, for which no collections regulations exist, also affects medicinal plants.

3. Environmental pollution:

Soil, water and air pollution affects the functioning of ecosystems and may reduce or eliminate sensitive species. For example, the decline of fish eating birds and falcons due to pesticide pollution. Lead poisoning is major cause of mortality of many species such as ducks and swans and cranes. In India, industrial effluents are destroying coral reefs and other marine life.

4. Global climate change:

In the coming years, climatic change could also affect global biodiversity. Many species which cannot adjust to the warmer climatic conditions could become extinct. A change in the climatic conditions may also result in the characteristics of habitats, there by affecting the species within those habitats. Some habitats such as islands and coastal systems, which are at risk of flooding and submergence due to rising sea levels, could suffer heavily, particularly high losses of biodiversity.

5. Invasion by introduced species:

The introduction of non native species deliberately or accidently has been a major threat to biological diversity worldwide. The introduced animals and plants pose a threat to local species of fauna and flora for eg: Lantana camera originally introduced as the ornamental plant from Brazil is spreading rapidly in our forests at the expense of local species. Water hyacinth clogs rivers and threatens the survival of many aquatic species in the several tropical countries, including India.

6. Nature of legal systems:

In planning legal enforcements, a perfect combination of economic realities and involvement of the people is required. Protection for wildlife in India is negligent. Parks do not have enough rangers to keep out poachers and villagers are often allowed to live within sanctuaries, which leads to growing conflicts between the local populations and animals particularly tigers.

7. Mining:

Every mining activity involves digging up tones of earth in orders to get to the ore. In the process it leads to deforestation and consequently, the biodiversity of the particular place is threatened. Moreover, the streams are polluted with dangerous chemicals.

8. Exploitation of water resources:

Over exploitation of surface water creates water scarcity in the absence of rainfall and the water pollution harms the aquatic diversity and ultimately threatens its survival.

9. Forest life:

Fire plays an important role in the forest ecosystems. Common causes include lightning, human carelessness, volcanic eruption, etc. Fires in forest due to natural or manmade reasons harm the insects, birds, and wild animals.

10. Eutrophication

Over the past four decades, nutrient loading has emerged as one of the most important factors of biodiversity loss in terrestrial, fresh water, and coastal ecosystem. Excessive nutrient enrichment of water bodies stimulates the growth of algae and lowers oxygen production. It leads to the death of fish and other aquatic organisms.

11. Waste disposal:

Dumping of nuclear and radioactive waste on land or water kills the plant and animal species leading to their extinction.

12. Other factors:

Other ecological factors that may also contribute to the extinction of plant and animal species are as follows;

· Distribution range: The smaller the range of distribution, the greater the threat of extinction.

· Degree of specialization: The more specialized an organism is, the more vulnerable it is to extinction.

· Position of organism in food chain: The higher the organism is in food chain, the more susceptible it becomes.

· Reproductive rate: Large organisms tend to produce fewer off springs at widely spaced intervals.

7.Write an essay on conservation of biodiversity.

Conservation Of Biodiversity:

Everyday, around the globe, species are being lost and others are being pushed towards extinction. This threatened biodiversity needs to be conserved. Biodiversity conservation is scientific management at its optimum level and derives sustainable benefits for both the present and the future

In situ conservation:

In situ means the natural or the original place. In this method, the plants and animals are conserved in their natural habitats.

National Parks:

A national park conserves the environment and the wild life therein. National parks are areas dedicated to conserve wild animals and natural environment. All private rights are non-existent and all forestry operation and others usages such as grazing of domestic animals are prohibited in these areas. Conservation of species of a habitat with minimal or very low intensity of human activity occurs in a natural park. No one apart from the public servant on the duty and permitted persons by chief wildlife warden resides in the park. In India, there are 90 national parks.

Wild life sanctuary:

A wild life sanctuary is dedicated to protect wild life, but it considers the conservation of species only and its boundary is not limited by the state legislation. Hunting without permit is prohibited and grazing and movement of cattle is regulated in sanctuaries and absolutely prohibited in Natural Park which is established in or outside a sanctuary. In a sanctuary, human activities are allowed but in national park human interference are totally prohibited. Conservation of species and habitats occurs by manipulative management. No person resides in the park other than the public servant on duty and permitted persons by the chief wild life wardens. It comprises of core, buffer and restoration zones. In India, there are 492 wild life sanctuaries.

Biosphere reserve:

Biosphere reserves have been described as undisturbed natural areas for scientific study as well as areas in which conditions of disturbances are under control. They have been set aside for ecological research and habitat preservation. Conservation of natural resources and improvement of the relationship between man and environment is the chief objective of biosphere reserves. In India 13 biosphere reserves have been established. A biosphere reserve consists of core, buffer, restoration and cultural (transition) zones. The core zone comprises of an undisturbed and legally protected ecosystem. The buffer zone surrounds the core area and is dedicated to research and educational activities. The transition zone is the outermost part of the biosphere reverse where activities like settlements, agriculture, forestry and recreational activities occur in harmony with conservation goals.

The in situ conservation application is advantages in many respects, but also has certain limitations.

The advantages of in situ conservation are:

· Long term protection

· Natural ecosystems spread in large areas provide a good opportunity for conservation as well as evolution

· Cheaper means to protect the species

The limitations of in situ conservation are:

· Proper protection against environment pollution may not be enough in natural ecosystems.

Ex situ conservation

In this technique, plant and animal species are conserved their natural habitats. Ex situ conservation is the chief mode of preservation of genetic resource. This can be done through establishment of gene banks, zoos, botanical gardens, culture collections etc

Gene banks

Gene banks also known as germplasm banks are established for ex situ conservation. Here seeds, pollen grains, vegetative propagating parts of various endangered plants can be preserved in viable conditions. The result of storing seeds under frozen conditions is to slow down the rate at which they lose their ability to germinate. Seeds of crop plants such as maize and barely could probably survive thousand of years in such conditions. A range of crops like millets, oil seeds, vegetables, turnip can be maintained for several years in liquid nitrogen without any decline in viability.

Botanical gardens:

Rare and endangered plant species are conserved in botanical gardens. In addition to conservation in botanical gardens, they are also used for the purpose of study and research of specific plant characters and for disseminating scientific information and experience to promote sustainable development


The aquaria are mainly for captive propagation of threatened or endangered fresh water species. It also finds its role in the educational facilities. However, now it is assuming new importance in captive breeding programmes. The world conservation Union is currently developing captive breeding programmes for endangered fish.

Tissue culture technique:

Tissue culture is a special type of asexual propagation where a small piece of shoot apex, leaf section, or even an individual cell is cut out and placed in sterile culture container containing a special culture medium. The culture medium contains a gel with the proper mixture of nutrients etc which causes the plant to grow at very rapid rates to produce new plantlets. A very specialized laboratory is required for tissue culture. The tissue culture is used for rapid multiplication of plants.

DNA technology

In this technique, the whole DNA of a plant or animal is conserved or a part of it is conserved. Through the use of recombinant DNA, genes that are important can be isolated and used in other species or applications, where they may be some from of genetic illness or discrepancy and provide a different approach to biodiversity conservation

Cryo preservation:

In vitro conservation in liquid nitrogen at that temperature of -196oC is quite useful for conservation of vegetatively propagated plants.


· Long term conservation

· Due to controlled supervision ,assured food ,shelter and security the species can survive longer and may breed more offspring than they usually can

· The quality of offspring may be improved by genetic techniques

· Breeding of hybrid species is possible.

The limitations of ex situ conservation:

· Not a viable option for protection of rare species due to human interference

· Can be adopted for only a few kinds of species

· Overprotection may result in loss of natural properties

Steps to Preserve Biodiversity:

· No undisturbed land be used for setting industries or other developmental works, because it leads to loss biodiversity

· Population growth should be controlled

· Measures should be taken to reduce environmental pollution

· Effective measures for conservation of biodiversity be developed and strengthened in all countries

· Germplasm for existing species should be collected


1. What is pollution and pollutant?

Pollution is any addition to air, water, soil or food that threatens the health, survival or activities of humans or other living organisms.

The toxic substances which adversely change the environment are known as pollutant.

2. Mention the harmful effects of pollutants.

1.Disruption of life support systems for humans and other species.

2.Damage to wild life, human health, property.

3.Nuisance such as noise and unpleasant smell, taste and sight.

3. Define air pollution?

Air pollution is the presence of one or more chemicals in the atmosphere in sufficient quantities and duration to cause harm to us, other forms of life and materials or to alter climate.

4. What is photochemical smog?

It is a mixture of more than 100 primary and secondary pollutants formed under the influence of sunlight.

5. What are the four most dangerous indoor air pollutants?

The four most dangerous air pollutants are

1. cigarette smoke

2. formaldehyde

3. radioactive radon

4. Small fine and ultra fine particles.

6. Define water pollution?

Water pollution is any, chemical, biological or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses.

7. What is soil pollution?

Degradation of soil and land due to industrial, agricultural and by other human activities is called soil or land pollution.

8. What is marine pollution?

Dumping of waste and oil spillage in the oceans cause threat to marine ecosystem is called marine pollution.

9. What is thermal pollution?

Thermal pollution is the addition of excess of undesirable heat to water that makes it harmful to aquatic life and cause significant changes of normal activities of aquatic communities.

10. What is noise? How it is measured?

The unpleasant and unwanted sound is called noise. It is expressed in hertz (Hz) and is equal to the number of cycles per second. The loudness is measured in decibel scale (db).

11. Define degradable and non – biodegradable wastes?

If the pollutants are rapidly decomposed, they are said to be biodegradable pollutants.Eg. Sewage sludge.

If the pollutants don’t degrade or degrade slowly they are said to be non bio degradable wastes. Eg. Mercury, plastics.

12. What is tsunami?

Sometimes the earthquake occurs deep under the sea in oceanic trenches. The stronger of them generate powerful seismic sea waves called tsunami. Tsunami is a Japanese word which in English means “Harbour waves”.

‘Tsu’ means harbour.

‘Nami’ means waves.

13. What is land slide?

If the rock movement happens through the certain definite plane, then it is said to be land slide.


1. Write causes, effects and preventive measures of Air pollution.

Air Pollution is the presence of one or more chemicals in the atmosphere in sufficient quantities and duration to cause harm to us, other forms of life and materials or to alter climate.

Types of Air Pollutants:

1. Primary air pollutants : emitted directly in the troposphere

2. Secondary air pollutants: Some primary pollutants may react with one another to form new pollutants.

Major air pollutants found in the atmosphere are: CO, NO2, SO2 SPM, O3, Lead.

Carbon mono oxide (CO): colorless, odorless gas that is poisonous to air breathing animals.

Source: Incomplete combustion, Cigarette smoking, motor vehicle exhaust

Health effects:

1. Reacts with hemoglobin in RBC and reduces the ability of blood to bring O2 to body cells and tissues.

2. Aggravates chronic bronchitis, emphysema, and anemia.

3. At high level cause coma and death.

Nitrogen di oxide (NO2): Reddish brown irritating gas that gives photo chemical smog its brownish colour.

Source: Motor Vehicle, power and industrial plants

Health Effects: Lung irritation and damage, aggravates asthma and chronic bronchitis

Environmental effects: Reduces visibility. HNO3 damage soil, trees and aquatic life in lakes.

Property damage: Corrode metals; eat away stone, statues and monuments.

Sulphur di oxide (SO2): Colorless irritating gas.

Source: Coal burning power plastics

Health effects: Breathing problem, chronic exposure leads to bronchitis

Environmental effects: Reduces visibility, acid deposition

Property damage: Can corrode metals; eat away stone and statues. Damages paint, paper, and leather.

Suspended particulate matter (SPM): Variety of particles and droplets.

Sources: burning fossil fuel, vehicle, agriculture, and construction unpaved roads.

Health Effects: Nose and throat irritation, lung damage and bronchitis.

Environmental effects: Reduces visibility, acid deposition

Property Damage: Corrodes metals Soils, and discolor buildings, clothes fabric and paints.

Ozone (O3): Highly irritating gas with an unpleasant odor that forms in the troposphere as photochemical smog.

Sources: Chemical reaction with volatile organic compounds and NO2.

Health effects: Breathing problems, coughing, eye, nose and throat irritation, aggravates, asthma, bronchitis emphysema.

Environmental Effects: Damage plants, trees, reduce visibility

Property Damage: Damages rubber, fabrics and paints.

Lead: Solid toxic metal and its compounds emitted into the atmosphere as particulate matter.

Sources: Paint, Smatters, lead manufacture, storage batteries leaded gasoline.

Health effects: Accumulates in the body, brain and other nervous system and damage brain and cause mental retardation, cancer, digestive problem.

Environmental Effect: harm wild life.

Photochemical smog: (Brown Air Smog)

A photochemical reaction is any chemical reaction activated by light. Air pollution known as photochemical smog is a mixture of more than 100 primary and secondary pollutants formed under the influence of sunlight.

Industrial Smog: (Gray – Air Smog)

During winter people in such cities were exposed to industrial smog consisting mostly of SO2, suspended droplets of H2SO4 and a variety of suspended solid particles and droplets called aerosols.

Indoor Air pollution:

According to EPA studies, 11 Common pollutants generally are two to five times higher inside homes and commercial buildings.

The four most dangerous indoor air pollutants are cigarette smoke, formaldehyde,

Radioactive radon and very small fine and Ultra fine particles.


Substance Indoor Pollutants


Possible Threat



Chlorine treated water with hot showers



Para dichlorobenzene

Air freshner, naphtha ball crystals



Tetrachloride ethylene

Dry cleaning fluid fumes on clothes

Nerve disorders, damage to liver and kidneys, possible cancer



Furniture stuffing, paneling, foam insulation

Irritation of eyes, throat skin, lungs nausea, dizziness


Benzo α Pyrenes

Tobacco, wood stove

Lung Cancer



Carpets, Plastic products

Kidney, liver damage



Faculty furnace, unvented gas stoves, kerosene, heaters

Headaches, Drowsiness, death.


Methylene chloride

Paint strippers, thinners

Nerve disorders, diabetes.



Radioactive soil, rock surrounding foundation

Lung Cancer



Pipe insulation, Vinyl ceiling and floor titles

Lung disease, cancer


Nitrogen Oxides

Unvented gas stove, wood stove

Irritated lungs, children’s cold.


1,1,1 Trichloroethylene

Aerosol sprays

Dizziness, irregular breathing

Effects of Air pollution:
Cause asthma, acute shortness of breath, lung cancer, chronic bronchitis, emphysema.
According to WHO at least 3 million people die prematurely each year from the effects of air pollution.
Affects plants because of soil nutrient depletion, and increased susceptibility to pests, disease fungi and drought.
Air pollutants cause billion of dollars in damage to various materials we use.
Damage marble statue
Damage historic buildings
Stained glass, pitted, gouged, discolored.
Break down paint on car and houses
Deteriorate roofing material
Acid rain
Destroys ozone layer depletion.
Global warming.
Photochemical smog

Control measures:
Source Correction:

The root cause of pollutant will be reduced by incorporating certain changes in the production process of an industry or by changing the raw material.

E.g. using lead free petrol
Control methods:

By incorporating suitable control equipments

E.g. ESP, Cyclone, Scrubbers.
Enforcing laws / policies:

Air Act should be followed strictly to reduce air pollution.

The Kyoto and Montreal protocol should be strictly followed by all the nations.

International co-operation is very much essential to reduce green house gas emission.
utilization of alternate energy

To reduce air pollution, Instead of using petrol, diesel and coal for energy generation, it is necessary to switch over for renewable energy sources like solar kind and biomass energy.

2.Write causes, effects and preventive measures of Water Pollution.

Water pollution is any chemicals, biological or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses.

Water Quality:-
Measuring the number of colonies of coliform bacteria present in a water sample.

WHO recommends zero colonies / 100ml for drinking water.

US, EPA recommends maximum level for swimming water of 200Colonies /100ml.

2. Water pollution from Oxygen demanding wastes and from plant

Nutrients can be determined by measuring the level of dissolved oxygen

3. To measure the BOD biological Oxygen demand to determine the

Quantity of oxygen demanding wastes in water.

4. Chemical analysis is widely used to determine the presence and concentration of inorganic and organic chemicals that pollute water.

5. Living organisms as indicator species to monitor water pollution.

Point sources: - Discharge pollutants at specific location through pipes, ditches or sewers into bodies of surface water.

Non point sources: - Cannot be traced to any single site of discharge. They are usually large land areas or air sheds that pollute water by runoff, subsurface flow or deposition from the atmosphere.


Sewage that includes organic matter, animal and human excreta-one of the major pollutants of water in the urban and rural areas is the sewage. The sewage most often contains the organic matter that encourages the growth of microorganisms. These organisms besides spreading diseases also consume the oxygen present in water. This is called oxygen depletion. The aquatic organisms like the fish cannot then survive in such waters. This creates an imbalance in the aquatic ecosystems.


The industries are mostly situated along the riverbanks for easy availability of water and also disposal of the wastes. But these wastes include various acids, alkalis, dyes and other chemicals. They change the pH of water. There are also detergents that create a mass of white foam in the river waters.

The industrial wastes include toxic metals like lead, mercury, cadmium, etc, and other chemicals like the fluorides, ammonia, etc.

Certain industries such as power plants, refineries, nuclear reactors release a lot of hot water from their cooling plants. This hot water is let into the water bodies without the temperature being reduced. This results in heating up of the water and thereby killing the aquatic life. The oxygen content of water also becomes less due to increase in the temperature. This is called thermal pollution.


Modern methods of agriculture have resulted in use of fertilizers and pesticides to increase the yield of the crops. These chemicals enter into the water bodies with the rain water flow and the ground water by seepage. The chemicals remain in the environment for a long time and can enter the food chain. They cause a number of problems in the animals.


Oil spill is a major problem in the oceans and seas. The oil tankers and offshore petroleum refineries cause oil leakage into the waters. This pollutes the waters.




Sewage that includes domestic wastes, hospital wastes, excreta, etc.

Sewarage of rural and urban areas.

Oxygen depletion Spread of diseases/ epidemics


Industnal wastes

Minamata disease (resulted from the contaminated waters of the Minamata bay in Japan in 1953) - causes numbness of limbs, lips and tongue, blurred vision, deafness and mental derangement.


Industrial wastes

Absorbed into blood and affects PBCs, liver, kidney, bone, brain and the penpheral nervous system. Lead poisoning can even lead to coma.


Cadmium industnes, fertilisers

Deposited in organs like the kidney, pancreas, liver, intestinal mucosa, etc. Cadmium poisoning causes headache, vomiting, bronchial pneumonia, kidney necrosis, etc.



Arsenic poisoning causes renal failure and death, It can cause nerve disorder, kidney and liver disorders, muscular atrophy, etc.

Agrochemicals like DDT


Accumulates in the bodies of fishes, birds, mammals including man. Adversely affects the nervous system, fertility. Causes thinning of egg shells in birds.

Pollution of freshwater steams, lakes and Groundwater:-

Flowing streams, including large ones called rivers can recover rapidly from degradable oxygen demanding wastes and excess heat through a combination of dilution and bacterial decay.

Clean zone – Decomposition zone – Septic zone – Recovery zone

In lakes and reservoirs, dilution of pollutants often is less effective than in streams for reasons. First, lakes and reservoirs often contain stratified layers that undergo little vertical mixing and second, they have little flow. Consequently, lakes and reservoirs are more vulnerable than streams to contamination. These contaminants can kill bottom life and fish and birds that feed on aquatic organisms.

Eutrophication is the name given to the natural nutrient enrichment of lakes.

Cultural Eutrophication - Near urban or agricultural areas, human activities can greatly accelerate the input of plant nutrients to a lake, which results in a process known as cultural Eutrophication.

Ground water pollution comes from numerous sources. People who dump or spill gasoline, oil and paint thinners and other organic solvents onto the ground also contaminates water.

When groundwater contaminated it cannot cleanse itself of degradable wastes as flowing surface water does Ground water flows slowly that contaminants are not diluted and disposed effectively.

Arsenic pollution causes various abnormalities causing skin lesion like leprosy.

Nitrate when present in excess in drinking water causes blue baby syndromes or methaemoglobinemia. The disease develops when a part of heamoglobin is converted into non functional oxidized form.

Excess of fluoride in drinking water causes defects in teeth and bones called floozies.

Effects of water Pollution:-

Ø Oxygen demanding wastes deplete dissolved oxygen in the water body which may be harmful to animals.

Ø Eutrophication also results in overgrowth of plants like Eicchornia that covers the entire surface of water. This reduces the light reaching the lower layers in water. Thus, enrichment of water with inorganic nutrients like nitrates and phosphates is called eutrophication.

Ø Pollutants accumulate in the organisms and cause serious health problems. The contamination of water with these pollutants results in their entry into the microscopic plants and animals. These organisms are fed upon by higher aquatic life like the fish. The fish in turn are fed upon by the land animals including man.Thus, the pollutant reaches the body of man. At each step in the food chain, the contaminant increases in quantity. This is because a fish feeds on large quantity of smaller plants and man eats fish. These contaminants like DDT remain in the fats and are not degraded in the body. Over the years the amount of DDT increases in the body. This is called biomagnification.

Ø Oxygen depletion and cause Eutrophication.

Ø Waste water contain many pathogen & viruses, Water borne disease such as cholera, dysentery, typhoid, jaundice etc are spread by water contaminated with sewage.

Ø Pollutants such as pesticides are non biodegradable and accumulate in the food chain known as Biomagnifications / bioaccumulation

Ø Pollution of water by organic wastes is a major cause for occurrence of epidemics like cholera, gastroenteritis in India. In fact, a good indication of pollution of water is the presence of bacteria E. coli that lives in the human intestines.

Ø Nitrogen & phosphorus helps in the growth of algae which when die and decay consume oxygen of water. Under anaerobic condition foul smelling gas is produced. Changes in pH, O2, temperature will change many physico – chemical characteristics of water.

Ø Toxic substances polluting the water ultimately affect human health. Some heavy metals like Pb, Hg, Cd cause various types of diseases.

· Minamata diseases:- Numbness of body parts, vision and hearing problem, abnormal mental behavior occurred due to consumption of methyl mercury contaminated fish

· Itai – itai disease caused by cadmium contaminated rice. Bones, liver, kidney, lungs, pancreas and thyroid are affected.

Control of water pollution

1. Prevent Ground water contamination.

2. Greatly reduce non point runoff

3. Reuse treated waste water for irrigation

4. Find substitutes for toxic pollutants.

5. Work with nature to treat savage.

6. Practice four R’s of resource use (Refuse, Reduce Reuse, Recycle).

7. Reduce resource waste

8. Reduce birth rates.

9. Use Nitrogen fixing plants to supplement the use of fertilizers.

10. Adopting Integrated pest management to reduce reliance on pesticides.

11. Planting trees would reduce pollution by sediments.

12. For controlling water pollution from point sources, treatment of waste water is essential.

13. Waste water should be properly treated by primary and secondary treatments to reduce the BOD, COD levels to the Permissible levels.

14. Advanced treatment for removal of nitrates & phosphate.

15. Proper Chlorination should be done to prevent the formation of chlorinated hydrocarbons or disinfection should be done by ozone or UV.

Sewage Treatment

The sewage before being let into the water bodies must be purified.

This is done in three steps as follows:
Primary treatment
Secondary treatment
Tertiary treatment
Effluent treatment

Primary Treatment

The water is sieved through coarse sieves and made to stand in sedimentation tanks. This makes the heavy suspended matter settle down. It is then passed through a bed of rocks.

Secondary Treatment

The organic materials that are biodegradable are treated with the help of decomposers and oxygen. Then, the water is also chlorinated to remove the germs.

Tertiary Treatment

This step removes the inorganic pollutants like the nitrates, phosphates, detergents, metal ions, etc. by passing the water through activated charcoal that acts as a filter.

Effluent Treatment

The industrial wastes should be treated before being let into the water bodies. The toxic materials should be removed, the metallic compounds should be precipitated, the acids and alkalis should be neutralized and the temperature of the hot waters should be reduced.

Public Awareness

The public should be made aware of the dangers of water pollution. This will ensure that the water bodies are not contaminated and are maintained clean

It can take 100-1000 years for contaminated ground water to cleanse itself of degradable wastes.

3.Write causes, effects and preventive measures of Soil Pollution.

Degradation of soil and land due to industrial, agricultural and by other human activities is called soil or land Pollution.


1) Industrial wastes

2) Urban waste

3) Radio active pollutants

4) Agriculture practice

5) Chemical & metallic pollutants

6) Biological agents

7) Mining

8) Resistant objects.

1) Industrial waste

- Fly ash from stone quarries, thermal power plant, cement factories.

- Cement & steel industries disturb the salt balance and destroy the fertility

- Textile and dyeing industries effluents affect the soil property.

- Chrome tanning involves huge quantities of chemicals which are very harmful to soil.

- Sludge of Industrial waste contain toxic heavy metals and pollute the soil.

2) Urban Waste:-

It comprises both commercial and domestic waste.

- Solid waste and refuse contribute to soil pollution.

- Plastic bags prevent the growth of plants, it kill animals it contain harmful chemicals & dyes.

- Urbanization produce enormous solid waste which leads to soil pollution.

3) Radioactive Pollutant:-

Radioactive substances resulting from explosive and radioactive waste, penetrate the soil and accumulate there creating soil / land pollution.

4) Agricultural practices:-

Using various pesticides, fertilizers, herbicides fungicides, weedicides and soil conditioning agents the crop yield has been increased, but these chemical pollute the soil and also clears the fertility of the soil.

5) Biological agents:-

Soil gets large quantities of human, animals, and birds excreta which constitute the major source of land pollution by biological agent. Biomedical waste poses great threat to the soil conditions.

6) Mining: - Mining & ore processing activities spoil the land.

7) Resistant objects:-

Large resistant objects such as can, plastic, tyres, glasses, used vehicle, refrigerator etc dumped in to nature; destroy the beauty of the landscape

8) Changing forest into agricultural lands.

9) Laying roads change the stability of slope & hydrological system in the hilly region.

Effects of soil pollution:-

- Sewage and industrial effluents which pollute the soil, ultimately affect human health.

- Various types of chemicals, acid, alkali pesticides, fertilizer, heavy metals affect soil fertility by causing changes in physical, chemical and biological properties.

- Some persistent toxic chemicals inhibit the non-target organism, soil flora and fauna and reduce soil productivity.

- Sewage sludge has many pathogenic bacteria, viruses, and intestinal worms which may cause various types of diseases.

- Decomposing organic matter in soil also produces toxic vapours

- Radioactive fallout on vegetation is the source of radio isotopes which enter the food chain in grazing animals.

Some of this radio isotopes replace essential elements in the body and cause abnormalities.

- Chemicals or their degradation products from soil may percolate and contaminate ground water resources.

- Applications of the pesticides also affect the micro-organism living in the soil.

- Because of soil pollution, the pH of the soil is changed and affects the Crop yield.

- It changes the porosity of the soil and affects the infiltration, water storage of the region.

- Pesticides, some heavy toxic metals & chemicals, are known to cause migraine, dizziness, stomach and abdominal cramps.

- In long run, accumulation of toxins inside the body can cause cancer, reduce fertility and immunity.

Control measures:-
Effluents should be properly treated before discharging them on soil.
Solid waste should be properly collected and disposed off by appropriate method.
From the wastes, recovery of useful products should be done.
Biodegradable waste should be used for generation of biogas.
Cattle dung should be used for CH4 generation.
Microbial degradation of degradable substances also reduces soil pollution.
Agro forestry programme for reclaiming degraded land soil is needed.
Integrated pest management.
Organic farming.
Biomedical waste treatment facilities like incinerator, autoclave, microwave systems should be installed in hospital & medical institutions.

4.Write causes, effects and preventive measures of Marine Pollution.

- Oceans are the ultimate sinks for much of the waste matter we produce.

- Oceans can dilute, disperse and degrade large amounts of raw sewage, sewage sludge, oil and some types of degradable industrial wastes, especially in deep water areas.

Sources and Effect of Pollutants on Coastal Areas:-

- Areas along coast – especially wetlands and estuaries, coral reefs and mangrove swamps bear the brunt of our enormous inputs of pollutants and wastes into the ocean.

- In most coastal developing countries, municipal sewage and industrial wastes are dumped into the sea without treatment. This causes widespread beach pollution and Shellfish contamination.

- Recent studies of coastal water have found vast colonics of human viruses from raw sewage, effluents from sewage treatment plant and leaking septic tanks.

- Some people using polluted coastal beaches develop ear infections, sore throats, eye infection, respiratory disease or gastro intestinal disease.

- Runoff of sewage and agricultural wastes into coastal water and acid deposition from the atmosphere introduce large quantities of Nitrate & phosphate plant nutrient which cause explosive growth of harmful algae.

- These harmful algae blooms are called red, brown or green tides, depending on their color.

- They can release waterborne and air borne toxin that can damage fisheries and kill fish eating birds, reduce tourism and poison sea food.

Effects of Oil on Ocean ecosystem:-

- Crude petroleum or refined petroleum is accidentally or deliberately released into the environment from a number of sources.


- Tanker accidents and blowout at offshore drilling rigs release oil to the ocean.

- More oil is released to the ocean during normal operation of offshore wells, from washing oil tankers, releasing the oily water, from oil pipe line and storage tank leaks.

- Natural oil seeps also release large amounts of oil into the ocean.


The effects of oil on ocean ecosystem depend on a number of factors,

1) type of oil

2) type of aquatic system

3) amount released

4) distance of release from shore

5) time of year

6) weather conditions

7) average water temperature

8) Ocean currents.

- Volatile organic hydrocarbons in oil immediately kill a number of aquatic organisms especially in their vulnerable larval forms.

- Some other chemicals form tar like globs that float on the surface and coat the feathers of birds and the fur of marine animals. This oil coat destroys their natural insulation and buoyancy, causing many of them to drown or die of exposure from loss of body heat.

- Heavy oil component that sink to the ocean floor or wash into estuaries can smother bottom dwelling organisms such as crab, oyster, mussels and clams or make them unfit for human consumption.

- Some oil spills have killed coral reefs.

- Most forms of marine life recover from exposure to large amounts of crude oil within 3 years.

- But recovery from exposure to refined oil, especially in estuaries can take 10 year or longer.

- The effects of spills in coldwater and in shallow enclosed gulfs and bays generally last longer.

- Estuaries and salt marshes suffer the most & longest lasting damage.

Control / Prevent Marine Pollution:-

I) Toxic pollutants from industries and sewage treatment plants should not be discharged in coastal water.

II) Run off from nonpoint sources should be prevented to reach coastal areas.

III) Sewer overflows should be prevented by having separate sewer and rain water pipes

IV) Dumping of toxic hazardous waste and sewage sludge should be banned.

V) Developmental activates on coastal areas should be minimized.

VI) Oil and grease from service stations should be processed for reuse.

VII) Oil ballast should not be dumped into sea.

VII) Ecologically sensitive coastal areas should be protected by not allowing drilling.

5.Write causes, effects and preventive measures of Thermal pollution.

Industries like thermal power plant, nuclear power plant etc are utilizing more water for cooling purposes. After being used, the hot water is let off into near by sea, steam and other water bodies. The hot effluent released from the above industries increases the temperature of the water body where it is discharged.

Thermal pollution is the addition of excess of undesirable heat to water that makes it harmful to aquatic life and cause significant changes of normal activities of aquatic communities.

Causes of thermal pollution:-

Nuclear power plants are the major pollution sources, emitting about 15% more heat per unit of electricity produced than the fossil fuel facilities.

Coal fired thermal power plants are some of the other sources of thermal pollution.

Municipal /Domestic sewage also raises the temperature of water bodies to some extent.

The textile, paper &pulp as well as sugar industries also release hot water but to a much lesser extent.

Effect of thermal pollution:-

1. The dissolved oxygen content of water is decreased as the solubility of oxygen in water is decreased at high temperature

2. High temperature becomes a barrier for oxygen penetration into deep cold waters.

3. Toxicity of pesticides, detergents & chemicals in the effluent increases with increase in temperature.

4. The composition of flora and fauna changes because the species sensitive to increased temperature due to Thermal shock will be replaced by temperature tolerant species.

5. Metabolic activities of aquatic organisms increase at high temperature and require more Oxygen, where as oxygen level falls under thermal pollution.

6. Discharge of heated water near the shores can disturb spawning and can even kill young fishes.

7. Fish migration is affected due to formation of various thermal zones.

Control of Thermal Pollution:-

The following methods can be employed for control of thermal pollution.

1. Cooling Ponds: Water from condensers is stored in ponds where natural evaporation cools the water, which can then be recirculated/ discharged in near by water.

2. Spray Ponds: The water from condensers is received in spray ponds. Here the water is sprayed through nozzles where fine droplets are formed. Heat from these fine droplets is dissipated to the atmosphere.

3. Cooling towers:-

1. Wet cooling tower: Hot water is sprayed over baffles. Cool air entering from sides takes away the heat and cools the water.

2. Dry Cooling tower: The heated water flows in a system of pipe. Air is passed over these hot pipes with fan. There is no water loss in this method.

6.Write causes, effects and preventive measures of Noise Pollution.

Sound is mechanical energy from a vibrating source. A type of sound may be pleasant to some one and at the same time unpleasant to others.

The unpleasant and unwanted sound is called noise.

Sound is expressed in Hertz and is equal to the number of cycles per second.

Decibel scale is a measure of loudness.

Noise can affect human ear because of its loudness & frequency.

Noise Standards recommended by CPCB committee





NOISE level in dB(A) Leq










Silence zone










1. Various modes of transportation ( air, road, rail – transportation)

2. Industrial Operations.

3. Construction activities

4. Celebration (Social / religious function, election etc)

5. Electric home appliances.

6. Blaring loud speaker

7. Bursting of crackers.

Effects of Noise pollution:-

1. Interferes with man’s communication.

2. Noise can cause temporary or permanent hearing loss. It depends on intensity and duration of sound level.

3. It causes high rate of accidents, general sickness, occupational, diseases, decrease in productivity.

4. It develops annoyance, irritation and fatigue in man.

5. Causes disturbance in his work, rest sleep, communication.

6. Causes diseases like nausea, headache, insomnia, loss of appetite, peptic ulcer etc.

7. When pregnant women exposed to longer duration in noisy region. She gives birth to defective and low weight baby.

8. It creates impaired hearing; break down of nervous system and high BP.

Control measures
Source reduction:

Stop the noise before it is generated. It refers applying control measures right at the noise source. Provide rubber pads on the foundation of heavy machineries, use of silencers, change the process which makes less noise.
Control at transmission path:

If noise is not controlled in the source, control measures like providing enclosures and barriers can be applied in the transmission path.
Control at the receiving end:

In some cases, the noise level cannot be reduced in the source level and transmission path. In this situation the individual protection devices like ear defenders, ear plugs, earmuffs etc. are used for human comfort.
Annual audio metric checkup is needed for persons working in all type of factories.
Planting trees and shrubs along roads in the hospitals educational institutions etc, help in reducing noise to a considerable extent.

7.Write causes, effects and preventive measures of Nuclear hazards.

Radio active substances are present in nature. They undergo natural radioactive decay in which unstable isotopes spontaneously give out fast moving particles, high energy radiations or both at a fixed rate until a new stable isotope is formed.

The isotopes release energy either in the form of gamma rays or ionization particles i.e. alpha particles and beta particles.

A α particles are fast moving positively changed particles whereas β particles are high speed negatively changed electrons.

These ionization radiations have variable penetration power; α particle is interrupted by a sheet of paper, β particle can be blocked by a piece of wood or few mm of Aluminium sheet.

Ƴ rays can pass through paper & wood, but stopped by concrete wall, lead slabs or water.


· Nuclear hazard is caused when there is the leakage of radiations from nuclear reactor, nuclear research, laboratories and industries.

· Accidents taking place in nuclear reactors.

· Transportation, disposal and storage of radioactive waste also cause the nuclear hazards.

· The process of mining and refining of radioactive ores also causes nuclear pollution.

· Radioactive isotopes mix with atmospheric air, when nuclear tests were conducted. This toxic substance present in the air later comes down to soil, water in the form of radioactive rain and combine with food chain of man.

· Sources of natural radioactivity include cosmic rays from outer space, radio active radon 222, soil rocks air, water and food, which contain one or more radioactive substances.

Effects of Radiations:-

- Radio active material act as environmental poison and damage the entire biota.

- Radionuclide Iodine 131 accumulate in the thyroid gland and affects the metabolic activities and cause leukemia (cancer of bone marrow )

- Radioactive debris which settles down on the earth’s surface after a nuclear explosion is called radioactive fallout. These explosions generate large amounts of nitric oxide molecules which react with the ozone and destroy the ozone layer.

- Neutron bomb is described as the ultimate weapon of destruction. It travels long distances at bullet speed and kills every one in its path within a day generally in few hours.

- Genetic damage is caused by radiations which induce mutations in DNA, thereby affecting genes & chromosomes. The damage is often seen in the off springs and may be transmitted up to several generations.

- Somatic damage includes burns, miscarriages, eye cataract, and cancer of bone, thyroid, breast, lungs and skin.

Control measures:-

1. To safe guard from the radiation effect, the radioactive waste should be buried deeply into the ground or buried under the ice sheets like Antarctic or Greenland ice sheets.

2. Ban on nuclear testing

3. Nuclear plant should have proper safety measures.

4. Proper disposal of wastes from laboratory involving the use of radio isotopes should be done

9. Write causes, effects and preventive measures of Solid Wastes.

- Higher standards of living of ever increasing population have resulted in an increase in the quantity and variety of waste generated.

- If waste generation continues indiscriminately then very soon it would be beyond rectification.

- Management of solid waste has therefore, become very important in order to minimize the adverse effects of solid wastes.

- Solid waste can be classified as municipal, industrial, medical, agricultural, mining waste and sewage sludge.

Solid waste is defined as “The material arising from human and animal activities and is being discarded as useless stuff.

The solid waste may either be biodegradable or non biodegradable waste. “If the pollutants are rapidly decomposed, they are said to be biodegradable pollutants like sewage sludge.

Instead, if the pollutants don’t degrade or degrade very slowly, they are said to be non-degradable pollutants like mercury and plastics.

Sources of solid wastes

· Wastes from homes: Contains a variety of discarded materials like polyethylene bags, empty metal, and Aluminum cans / scrap metals, glass bottles, waste paper, diapers, cloth/rags, food waste etc.

· Waste from shop: Mainly consists of waste paper, packaging material, cans, bottles, polyethylene bags, peanut shells, egg shells, tea leaves etc.

· Biomedical waste includes anatomical waste, Pathological waste, infectious waste etc.

· Construction / demolition waste include debris, rubbles wood, concrete etc.

· Horticulture waste includes vegetable pails and residues.

· Waste from slaughter house includes remains of slaughtered animal.

· Industrial waste consists of factory rubbish, packing material, organic wastes, acid, alkali and metals etc. During some industrial processing toxic and hazardous waste are also produced.

· Radioactive waste are generated by nuclear power plants

· Thermal power plants produce fly ash in large quantities.

Effects of solid waste:-

- Solid waste released from chemical industries is usually poisonous and is very harmful.

- Biological waste and waste discarded in the form of explosive from ordnance factories are dangerous to human life.

- The land disposed waste normally pollutes ground water and surface water.

- Some toxic wastes cause fire (if inflammable), release poisonous gases, and also even cause explosions.

- Solid waste pollutes the water body and affects the aquatic life.

- It causes obnoxious smell and affects surrounding area.

- It affects the texture of soil and reduces its fertility.

- Solid waste acts as breeding place for mosquitoes and flies, hence, producing various diseases.

- Causes soil sickness.

- Alters pH, porosity and permeability of soil.

Control measures:-

i) Collection and source segregation:

The term collection includes gathering or picking up of solid wastes from various sources. Segregation or sorting out of reusable material from the waste heap is the first step in the process of Solid waste management (SWM).

The main idea is to recover useful products from the waste before dumping.

ii) Open dump:-

Wastes are dumped into the outskirts of town/city.

It is the most common disposing method. It is simple and less expensive but undesirable due to air and water pollution.

iii) Sanitary landfill:-

Disposing of solid waste on land without creating hazards to human health and with safety is known as sanitary land fill.

It is safer and more advantageous than open dump.

iv) Composting:-

In this process, the decomposition and stabilization of solid wastes takes place by biochemical process under controlled conditions. Microorganisms are involved in this process.

It occurs in two ways.

i) Aerobic composition – O2 is utilized to feed on organic matter

ii) Anaerobic composition – decomposition occurs in the absence of O2.

v) Pyrolysis:-

It is the process in which the waste is heated (500-1000oc) to cause chemical changes in the absence of air.

vi) Incineration:-

The incineration involves the burning of solid waste at high temperature (850oc). The unburnt combustibles must be disposed of into the other dumps. The disadvantage of this process is air pollution.

vii) Biogas / fertilizer from solid waste:-

In a closed reactor the solid waste should be subjected to anaerobic decomposition to produce the biogas which is used as fuel.

The sludge of this process is dried and used as fertilizer/

Management of Solid wastes:-

i) Reduction in use of raw materials: Reduction in the use of raw materials will correspondingly decrease the production of waste.

ii) Reuse: The refillable containers which are discarded after use can be reused. From waste paper, silos and casseroles can be made.

iii) Recycle: It is the reprocessing of discarded materials into new useful products.

Formation of some old type products – old Al can melt & recast into new cans.

Formation of new products, preparation of fuel pellets form kitchen waste

The process of reducing reusing and recycling saves money, energy raw materials, land space and also reduces pollution.

2. How solid waste can be managed?

Solid Waste Management

Solid waste is defined as “The material arising from human and animal activities and is being discarded as useless stuff.

The solid waste may either be biodegradable or non biodegradable waste. “If the pollutants are rapidly decomposed, they are said to be biodegradable pollutants like sewage sludge.

Instead, if the pollutants don’t degrade or degrade very slowly, they are said to be non degradable pollutants like mercury and plastics.

Sources of solid wastes

· Wastes from homes:

· Waste from shop:

· Biomedical waste includes anatomical waste, Pathological waste, infectious waste etc.

· Construction / demolition waste include debris, rubbles wood, concrete etc.

· Horticulture waste includes vegetable pails and residues.

· Waste from slaughter house includes remains of slaughtered animal.

· Industrial waste

· Radioactive waste are generated by nuclear power plants

· Thermal power plants produce fly ash in large quantities.

Effects of solid waste:-

- Solid waste released from chemical industries is usually poisonous and is very harmful.

- Biological waste and waste discarded in the form of explosive from ordnance factories are dangerous to human life.

- The land disposed waste normally pollutes ground water and surface water.

- Some toxic wastes cause fire (if inflammable), release poisonous gases, and also even cause explosions.

- Solid waste pollutes the water body and affects the aquatic life.

- It causes obnoxious smell and affects surrounding area.

- It affects the texture of soil and reduces its fertility.

- Solid waste acts as breeding place for mosquitoes and flies, hence, producing various diseases.

- Causes soil sickness.

- Alters pH, porosity and permeability of soil.

Control measures:-

viii) Collection and source segregation:

ix) Open dump:-

x) Sanitary landfill:-

xi) Composting:-

xii) Pyrolysis:-

xiii) Incineration:-

xiv) Biogas / fertilizer from solid waste:-

3. Explain the disaster management for

i. Flood

ii. Earth quake

iii. Cyclone

iv. Land slides


Whenever the quantity of flow of water exceeds the carrying capacity of the channel within its banks, the excess water overflows on to the plains and causes floods.

According to the National Commission on floods, the area affected by annual floods now stands at around 40 million hectares.

Factors responsible for the occurrence of floods

Mitigation Measures:-

Earth quakes:-

An earth quake is a sudden vibration caused on the earth’s surface due to the sudden release of energy stored in the rocks beneath the earth surface.

High frequency waves travel in all directions from the focus point and create seismic shocks. The point immediately above the focus is called epicenter. The slight disturbances are known as earth tremors.

Effects of the earthquakes:-

Mitigation measures:-


Spirally moving storm developing in the Bay of Bengal and Arabian sea in the tropical belt is called cyclone.

The wide spread damage from fierce wind (exceeding 100-120km/hr) is quite common in coastal regions.

Mitigation measures:-

Land slides:-

The movement of earthy materials from higher region to lower region in the hilly and sloppy areas due to gravity is called mass movements.

If the rock movement, happens through the certain definite plane then it is said to be land slide.

Reasons for land slides:-

Mitigation Measures:-

4. Explain the role of an individual in controlling the pollution.

Each individual should change his/her life style in such a way as to reduce environmental pollution.

· Help more in pollution prevention than pollution control.

· Use ecofriendly products

· Cut down the use of CFC’s

· Use CFC free refrigerators.

· Reduce your dependency on fossil fuels

· Save electricity by not wasting it when not required

· Adopt and popularize renewable energy sources.

· Improve energy efficiency

· Promote reuse and recycling wherever possible & reduce the production of wastes

· Use mass transport system.

· Decrease the use of automobiles.

· For short distance use bicycle or go on foot.

· Use integrated pest management.

· Use rechargeable batteries. It will reduce metal pollution

· Use less hazardous chemicals

E.g. Baking soda can replace modern deodorants

· The solid waste generated during one manufacturing process can be used as a raw material for some other processes.

· Use organic manure.

· Do not put pesticides, paints, solvents, oils or other harmful chemicals into the drain or groundwater

· Use low PO4, PO4 free or biodegradable dish washing liquid, laundry, detergent & shampoo.

· Use only the minimum required amount of water for various activities. This will prevent fresh water from pollution.

· When building home save as many tree as possible in the area.

· Plant more trees.

· Check population growth, so that demand of materials is under control.

· It is the duty of individual to educate producers and consumers about environmental degradation and control.

· Individuals can help in cleaning beaches, rivers, lakes etc.

The can also help in creating litter free zone, environmental forestry zone, smokeless zone, noise free zone in the city area.

UNIT –III Natural Resources

2. What are natural resources?

The resources that occur in nature are called natural resources.

3. Mention few natural resources.

The important natural resources are

1. Forest resources.

2. Water resources.

3. Mineral resources.

4. What are renewable and nonrenewable resources?

· Renewable resources which are inexhaustible and can be regenerated

Eg- Forest, wind energy, biomass energy

· Non- renewable resources which are exhaustible and cannot be regenerated

Eg- Fossil fuel like coal, petroleum, minerals etc

5. Write any two functions of forest.

· To control water quality and quantity.

· To moderate the temperature.

· Shelter for wild animals.

6. What are the causes of deforestation?

a. Forest fire

b. Developmental projects like construction of dams.

c. Timber extraction.

7. What is the main purpose of the dam?

The main purpose of the dam is to capture and store run off and releases it as needed for controlling floods.

8. What is known as blue baby syndrome?

When the concentration of nitrate exceeds 25 mg/l, they become the cause of a serious health hazard called blue baby syndrome. Mostly it affects the infants.

9. What is eutrophication?

A large proportion of nitrogen & phosphates used in crop fields is washed off along with runoff water reach the water bodies causing over nourishment of the lakes, a process known as eutrophication.

10. Define water logging.

Water logging is the land where water stands most of the year.

11. What is desertification?

It is a progressive destruction of arid or semi arid lands to deserts.

12. What is meant by soil erosion?

It is the process of removal of superficial layer of the soil from one place to another.

13. Define overgrazing.

It is a process of eating away the forest vegetation without giving it a chance to regenerate.

14. List out any four adverse effects of mining.

a. Noise pollution, b. Earth quake, c. Land slides.

15. List few mineral resources available in India.

a. Iron – Bihar, Tamilnadu & Goa;

b. Coal – WB, AP, Bihar, MP

c. Gold – Karnadaka

d. Manganese – Orisa, MP, AP

16. State the problems caused by the construction of dams.

a. Displacement of tribal people.

b. Loss of Fauna and Flora.

c. Loss of non forest land.

3. What is deforestation? Discuss the causes and impacts of deforestation.8

Definition (2)

It is a process of removal of forest resources due to many natural or man-made activities.

Causes of Deforestation (3)

1. Growth of human population.

2. Shifting cultivation.

3. Timber extraction.

4. Forest fires

5. Fuel requirements

6. Requirement of raw materials for industries

7. Developmental projects and mining operations.

Effects or Impact of Deforestation (3)

Effect on climate

1. Global warming house effect is increased

3. Increasing sea level and depletion of ozone layer

Loss of genetic diversity

Forest is the greatest storehouse of genetic diversity on earth, which provides new food and medicine for the entire world.

Soil erosion - It causes landslides, floods, and drought.

4. Discuss the effects of dams on Forests and Tribal people.


Dams are artificial structure, which built across the river for irrigation, hydroelectric power generation and flood control.

For example; 1.kallanai across Cauvery in Tamil Nadu 2.The boulder dam in U.S.A.,

Effects of dams on forest

1. Thousands of hectares of forest are destroyed

2. Forests cleared for residential, office, store room roads construction

3. Hydro electric power projects destroys forest

4. Kills wild animals and aquatic life

5. Fertility of the land reduces

5. Write a detailed note on uses of forest.


Commercial uses:

timber, firewood, pulpwood, food items, gum, resins, non – edible oils, rubber, fibers, bamboo canes, fodder, medicine, drugs and many more items

Ecological uses:

v Production of oxygen.

v Reducing global warming.

v Wild life habitat.

v Regulation of hydrological cycle.

v Soil conservation.

v Pollution moderators.

6. Explain how the mining and dam construction activities affect the forests and tribal


Mining activity not only destroy trees. It also pollutes soil, water, with heavy Metal toxins that are almost impossible to remove.
Destruction of natural habitat
Due to continuous removal of Minerals & forest covers, trenches are formed on ground leading to water logged area which in turn contaminate ground water
Noise pollution due to Mining operations
Lands slides may also occur as a result of continuous Mining in forest area.
During Mining, vibrations are developed which leads to earthquake
When materials are distributed in significant quantities, during mining process large quantities of sediments are transported by water erosion.

7. Discuss the environmental effects of extracting and using mineral resources. (8)


1. Minerals are non renewable resources, which supplied by earth to mankind.

2. They are naturally occurring inorganic earth materials possessing certain physical and chemical properties.

3. They can be broadly classified in to types: metals such as copper, iron, aluminum; industrial minerals such as lime and soda ash; construction, materials such as sand and gravel; and energy minerals such as coal, uranium, oil, etc.

4. Metals are the most important and valuable minerals extracted from earth. For example, aluminum copper, zinc lead tin is extensively used in industry and many applications.

Uses and Exploitation of Minerals

Minerals are utilized in a large number of ways in everyday use in domestic, industrial, agricultural and commercial purposes.

Some important uses of minerals are given as follows.

1. Development of industrial plants and machinery. Examples. Iron, aluminum, copper, etc.

2. Building construction. Examples. Iron, aluminum.

3. Generation of energy. Examples. Coal, uranium, lignite, etc.

4. Agricultural purposes such as fertilizers Examples; Zineb – containing zinc.

5. Making of Jewelers Examples: Gold diamond and silver.

6. Medicinal purposes, particularly in ayurvedic system. Examples; Sulphur pyrites.


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