UNIT-IIINATURAL RESOURCES

PART-A

1. Define eutrophicationEutrophication is the enrichment of water by addition of nutrient like nitrogen and phosphorus. The

extra nutrients encourage the growth of algal blooms. These algae eventually die and decompose, removing the oxygen from the water and it cause the death of fish. This process is called eutrophication.

2. Differerentiate between renewable and non-renewable energy resourcesS.no Renewable Energy resource Non-Renewable Energy Resource1 They are natural resources which can

be regenerated continuously. It is used again and again

A non Renewable energy resource is an energy resource that is not replaced or it is replaced very slowly by natural process.

2 They can be regenerated and used again and again

They cannot be regenerated and cannot be used again and again

3 Examples: Solar energy ,Wind energy Ocean energy, Geothermal energy Biomass energy

Examples :coal, petroleum ,CNG,LPG, Nuclear energy

3. What are the three effects of deforestation?1. Shifting of people:

Due to deforestation, people from one area to another to meet their requirements.2. Loss of biodiversity:

Loss in biodiversity and on a natural global scale is known to cause the extinction of many species.3. Changes in climate:

The temperature will increase and loss in humidity will occur.

4. Suggest three damages caused by the use of fertilizers Micronutrient imbalance Eutrophication Blue baby syndrome Ground water pollution Soil acidity

5. List the advantages and disadvantages of hydel/hydro electric power

Advantages:

1.Electricity 2. Water Sports And Leisure / Pleasure Activities. 3 Irrigation Purposes.4No Pollution

Disadvantages:   1. Expensive To Build 2.Natural Environments Is Destroyed.3.Affect Aquatic Life4.Geological Damage

6. Define food securityFood security is a complex sustainable development issue, linked to health through malnutrition, but also

to sustainable economic development, environment, and trade. Food security is built on three pillars: Food availability Food access Food use

7. What are the factors that contribute to land degradation? Population Urbanisation Fertilizers and Pesticides Damage of top soil

8. What is cyclone?A system of winds rotating inwards to an area of low barometric pressure, with an anticlockwise

(northern hemisphere) or clockwise (southern hemisphere) circulation; a depression.

9. Mention the major environmental impacts of mining

Conversion of productive land into mining and industrial areas.

Mining and extraction process are one of the sources of air, water and land pollution.

Mining involves huge consumption of energy resources like coal, petroleum, natural gas etc. which are

in-turn non renewable sources of energy.

Surface mining directly degrades the fertile soil surface thus effect ecology and climate if that

particular area.

10. Define overgrazing and List the changes caused by over grazingOvergrazing is a process of, “eating away the vegetation without giving it a chance to regenerate”.

Effects of overgrazing/impacts Decreases the water holding capacity of the soil. The ground cover would be depleted causing soil erosion. The native plants would be replaced by less favourable plants The food web in the area would be disrupted

11. What are renewable resources?They are natural resources which can be regenerated continuously. It is used again and

again Examples: Solar energy = Solar cells, Solar heat collectors, Solar water heaterWind energy = Wind mills, Wind farmsOcean energy = Tidal energy, Ocean Thermal energy, Geothermal energy Biomass energy = Biogas, Bio fuel, Hydrogen fuel

12. Define the term landslide

Landslide or Landslip is a geological phenomenon.

The rapid downward and outward movement of sliding of a mass of earth and rock

The action of gravity is the primary driving force for a landslide Underwater landslide can cause Tsunami

13. What are non renewable resources? A non Renewable energy resource is an energy resource that is not replaced or it is replaced very

slowly by natural process. They cannot be regenerated and cannot be used again and again Examples are coal, petroleum, CNG, LPG and Nuclear energy

14. What is desertification?

Progressive destruction or degradation of a grass land or arid land into a desert is known as

desertification.

Such actions include Overgrazing, repeated burning, intensive farming and stripping of vegetation for

firewood

15. Define floodA flood is an overflow of an expanse of water that submerges land. Flooding may result from the

volume of water a body of water, such as a river or lake, which overflows and causes the water to get escape its usual boundaries.

16. What is drought?Drought is defined as a period in which a region has a scarcity in its water supply.

17. Explain nuclear fission and fusionNuclear Fission

Heavier nucleus is split into lighter nuclei, on bombardment by fast moving neutrons, and a large amount of energy is releasedNuclear fusion:

Lighter nucleuses are combined together at extremely high temperatures to form heavier nucleus and a large amount of energy is released.

18. Define Biodegradation and how it occursBiodegradation is a chemical dissolution of materials by bacteria or by other biological methodsIt occur in two ways

1. Mineralisation2. Biotransformation

19. Define bioconversion and its typesBioconversion is the process of converting the waste into useful source of energyTypes of Bioconversion

Enzymatic hydrolysis Synthesis gas fermentation Composting/Grub composting

20. Define biodegradable pollution and its types

Biodegradable matter is generally organic material such as plant and animal matter and other substances originating from living organisms, it pollutes the environment.Based on degradability, it is classified into 4 groups

1. Very easily degradable2. Easily degradable3. Potentially degradable4. Very slowly degradable

PART-B1. Explain the following in detail

(i) Mineral resource(ii) Food resource

(I) MINERAL RESOURCES

A mineral is a naturally occurring homogeneous inorganic solid substance having a definite chemical composition and characteristic crystalline structure, colour and hardness.

Ores A mineral or an aggregate of minerals from which a valuable constituent, especially a metal, can be profitably mined or extracted.

Formation of mineral depositsThe formation of mineral deposits is a very slow biological process. It may take millions of years to develop as a mineral deposit.

Various biological processes Mineral deposits are formed due to the biological decomposition of dead animals and organic matters. Mineral deposits are formed due to the concentration of minerals during cooling of molten rock.(lava

from volcano) Mineral deposits are formed due to the evaporation of the sea water. Mineral deposits are formed due to the concentration of minerals during weathering, transport and

sedimentation.

Mineral deposits can be classified into three main groups: Identified resources Undiscovered resources Reserve

Identified resourcesIdentified resources are a mineral resource which is known about their location, existence, quantity and quality by the direct geological evidence and measurements.Example: Russell gold deposit in South Carolina.

Undiscovered resourcesUndiscovered resources are a mineral resource which has not been discovered, but assumed to exist on the basis of geological knowledge and theory. Their specific locations, quality and quantity are unknown.Example: Tongass National Forest-South eastern Alaska.

ReserveReserve is a mineral resource which can be recovered at a profit.This will be a mine either in production or

going into production.Example: The Ekati Diamond mine in Northern Canada.

USES OF MINERALSMinerals provide important wealth to a country.The mineral are used for various purposes.

Industrial Use Industries like Iron,Aluminium,Copper,Chromate are mainly depending on the mineral resources.These industries provide an IMPORTANT economy to our country.

Agricultural UseUsed as Fungicide and Pesticide.Sulphur -Used for fungicides, sulphuric acid, explosives, kills bacteria, vulcanizes rubber, used in coal and fuels and fertilizers.Lubricants -Minerals are used as lubricantsGraphite - used in pencils and as lubricants for machinery.

For JewelleryDiamond - It is used in cutting tools, blades, saws and beautiful gemstones in jewellery.Gold - Used in dentistry and medicine, jewellery and arts.Silver -Uses include photography, jewellery, electronics, as currency, alloys.

PharmaceuticalsMinerals are used as pharmaceutical and in chemical industries for various purposes.Example: Bismuth replaces toxic lead in many applications.

Storage DevicesCadmium is used in plating and alloying, pigments, plastics and batteries.

Electrical Use Garnet is used in water filtration, electronic components, ceramics, glass, jewellery and abrasives used in wood furniture and transport manufacturing.

Important Mineral reserves in the world

(Explain mining and its types along with case study)

Mineral Uses Countries Bauxite ore of Aluminium Australia,Jamaica,Brazil.Chromium Alloys,Electroplating India,South Africa,Turkey.Copper alloys,Electric wires Chile,USA,Canada.Gold Jewellery Chile,USA,Canada.Iron ore Iron and steel Brazil,Australia,China,Canada and

venezuelaLead Solder,Pipes USA,Mexico,Canada.

MINING

Mining refers to the process of extracting metals and minerals from the earth.

Types of miningThere are basically two types of mining.1. Open-cast or surface mining2. Underground mining

1. Surface MiningThe minerals or rocks are mined at the surface or very close to the surface.There are many types of surface mining processes. They are

(a)Strip mining processThe surface of the earth is stripped and the soil, rocks that lie above is removed generally by heavy machinery and then the material is extracted.

(b)Mountain top processThis process involves blasting of the top of mountains and the minerals are extracted below it.

(c)Open pit processMining is done close to the surface, large open holes are dug in the ground. Explosives are used to get large blocks of rocks out of the way.

(d)Hydraulic mining processIn this process, high pressure water jets are used to dislodge rocks and minerals.

2. Underground miningUnderground mining is a technique used to access ores and valuable minerals by digging into the ground and extract them.

There are many types of underground mining process .They are (a) Slope mining process

Slopes are made into the ground and desired material is accessed .Coal is mined by this process.

(b)Hard rock processTunnels deep in the ground are dug sometimes with dynamite or large drills. Tin, Lead, Copper, Silver, Gold etc.., are mined by this process

3) Borehole processBy using a drill, a deep hole is dug and a high pressure water jet is used to force the materials up the hole .Sand, Galena, Gold etc., are mined by this process.

CASE STUDY

In 1995,in Guyana, more than four billion liters of waste water that contained cyanide, slipped into a river. All the fish in the river died, plant and animal life was completely destroyed and soils were heavily poisoned, making the land useless for agriculture. The main source of drinking water for the local people was also polluted.

(ii)FOOD RESOURCE

Food is an essential requirement for all living beings. The resources that are used as food or provided food for organisms are called as food resources. Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins and minerals.250.000 species exist on earth, and 100 are used to feed the world. 15 plants and 8 animal species supply 90% of food.Example: wheat, rice, corn/maize, potato.

Human depend on Croplands Range lands Oceanic fisheries

CroplandsCropland is a land which is fit or used for growing crops. It mostly produces grains and provides about 76% of the world’s food.Examples: rice, wheat, maize, millet, barley, etc.

Range landsRangeland is a collective term for native grasses and shrubs that cover an arid or semi- arid area. It produces food mainly from the grazing livestock.Examples: meat, milk, fruits etc

Oceanic fisheriesA fishery is an area with an associated fish or aquatic population which is harvested for its commercial value.Examples: fish, prawn, crab, etc.

Major food resourcesOur earth contains thousands of plants and animals.Plant as food resourcesPlants serve as food for herbivores and omnivores. Agriculture produces major food products namely cereals, pulses, species, beverages, fruits and vegetables.Animals as food resources Animals are the main sources of food for carnivores and omnivores. the meat of animal is the food source for many organisms.

(Explain the world food problems in detail and how it will affect the other resources)

World food problems The food problems are due to

Population pressuresEnvironmental degradation like soil erosion, salinity, water logging affects agricultural lands. In developing countries, urbanization is a major problem because it reduces the agricultural lands.

Under nutrition and malnutrition

Nutrition (or) nourishment -> deficiencies of specific nutrients To maintain good health human needs large amount of macronutrients like carbohydrates proteins, fat and micronutrients like vitamins and some minerals. Nutrients are essential to resist disease.

Under nutritionConsuming insufficient food to meet one’s minimum daily energy requirement for a long enough time to cause harmful effects is known as under nutrition.

Effects of under nutritionVisible effects- low weight, unhealthy appearanceUnseen effects-muscles, heart and lungs can begin to deteriorate

This can develop into fatigue, difficulty in breathing and when the body stops being able to produce enough healthy blood cells. it can result in the development of anaemia.

MalnutritionMalnutrition is the condition that occurs when human body does not get enough nutrients, proteins, essential fats, vitamins, minerals and other nutrients.

Effects of malnutritionProtein deficiency- weight loss, diarrhoea, stunted growthIron deficiency-anaemiaIodine deficiency- goitreVitamin a deficiency- blindness

(Discuss the impact of mining on environment and human health)

ENVIRONMENTAL IMPACTS OF MINING ACTIVITIES

Effects of Mining on Environment Loss of Vegetation

Mining techniques caused irreversible damage to trees ,birds and animals. Large scale deforestation takes place.

Loss of Aquatic life Release of toxic chemicals into the water is obviously harmful for the flora and the fauna of the water

bodies. During mining, sometimes mercury enters the food chain through aquatic animals. Cyanide, which is highly poisonous, is used to separate gold from sediment and rock. If cyanide is

released into the environment, it causes the damage to the aquatic life.Effects of mining on land loss of biodiversityForest provide home to a large number of organisms. Mining leads to loss of habitat of large number of animals.Pollution

Mining changes the chemical composition of the land .It changes the soil fertility.Effect on water pollution

Chemicals like mercury, cyanide, sulphuric acid, arsenic and methyl mercury are used in various stages of mining are released into nearby water bodies. They cause water pollution.Spread of disease

Water-borne diseases are caused due to the stagnant of water in the pits created during mining.

2. Discuss in detail about over exploitation of forest

Over exploitation means destruction and extinction of resources.

Factors causing over exploitation:The factors which leads to overexploitation are

The demand for raw materials Increase in population Increasing civilization Increase in industrial activities Mining activities Farming Forest fires River projects

Effects of over exploitation

Loss in biodiversity Fall in economic level Plant and animal species become endangered Climate changes in environment

3. Discuss the problems associated with over exploitation of (i) Mineral resource (ii) Ground water

OVER EXPLOITATION OF MINERAL RESOURCE:

(a)Mining is hazardous occupation:

1. This occupation involves several health risk dust produced during mining operation are injurious to health

and cause lung diseases.

2. Extraction of some toxic or radioactive minerals leads to life threatening hazards.

3. Dynamite explosion are extremely poisonous.

4. Underground mining is more hazardous than surface mining as there are more chances if accidents like roof

falls, flooding and inadequate ventilation etc.

(b) Rapid depletion of high grade minerals:

Increasing demand for high grade minerals has compelled miners to carry out more extraction of minerals,

which require more energy sources and produce large amount of waste materials.

(c) Wastage of upper soil layer and vegetation:

Surface mining results in the complete destruction of upper soil layer and vegetation. After extraction, the

wastes are dumped in an area which destroys the total surface and vegetation.

(d) Environmental problems:

Over exploitation of mineral resources resulted in many environmental problems like:

1. Conversion of productive land into mining and industrial areas.

2. Mining and extraction process are one of the sources of air, water and land pollution.

3. Mining involves huge consumption of energy resources like coal, petroleum, natural gas etc. which are in-

turn non renewable sources of energy.

4. Surface mining directly degrades the fertile soil surface thus effect ecology and climate if that particular

area.

OVER EXPLOITATION OF WATER:

The rapid increase in demand for water resources has increased ground water usage.

Effects of over exploitation are:

1) Decrease in ground water:Ground water level decreases due to increased usage of ground water.

Causes: The erratic and inadequate rainfall The building construction activities

2) Ground subsidence :The ground water withdrawal is more than its recharge rate. It is most often caused by human activities, mainly from the removal of subsurface water.Problems:

structural damage in buildings fracture in pipes reversing the flow of canals and tidal flooding

3) Lowering of water table:Over utilization of ground water leads to lowering the water tableProblems:

lowering the water table Decreased pressure in the aquifers and changes in the speed and direction of water flow.

4) Intrusion of salt water:In coastal areas, over exploitation of ground water would lead to rapid intrusion of salt water from the sea.

5) Earthquake and landslides:Over utilization of ground water leads to decrease in water level, which cause earthquake, landslide, and famine.

6) Drying up of wells:

As a result of over utilization of ground water, the level of ground water gets depleted at a much faster rate than their regeneration. This leads to drying up of dug wells and bore wells.

7) Pollution of water:When ground water level near the agricultural land decreases, water, containing the nitrogen as nitrate fertilizer, percolates rapidly into the ground and pollutes the ground water.

Problems: structural damage in buildings fracture in pipes reversing the flow of canals and tidal flooding

8) Water Logging :When excessive irrigation is done with brackish water, it raises the water table gradually leading to water logging and salinity problems.

9) Loss of integrity of fresh water ecosystems Human activities for infrastructure development like creation of dams, land conversion, etc. are responsible for this loss of integrity of fresh water ecosystems. Water quality and quantity, fisheries, habitats, etc. are at risk due to this loss of integrity.

10) Risk to ecosystem functions :Population and consumption growth increase water pollution. Virtually all ecosystems functions including habitat, production and regulation functions are at risk.

4. Discuss the benefits and problems of dams with reference to case study

A barrier constructed across a waterway to control the flow or raise the level of water. dams are the artificial structures constructed across the river to store water. Dams are constructed for a specific purpose such as water supply, flood control, irrigation, navigation, sedimentation control and hydropower

BENEFITS OF DAMS

Water storageFor domestic and industrial purposeUrban depend on stored waterUsed in the time of low rain fall

Agricultural demandsMeeting the needs of agricultural irrigationHelp agriculture to meet the water scarcity

Flood controlDams and reservoirs are used to maintain water levels in the river

Recreational purposeIt is especially used in the areas where there is lack of surface water

Habitat for aquatics

Excellent habitat for fishes, reptiles and aquatic plants

Electrical generationIt generate hydro electric power, which is clean, dependable, efficient and renewableIt does not contribute global warming, pollution, acid rain and ozone depletion.

PROBLEMS OF DAMS

Soil erosionDams erode the land

Species extinctionInterfere with lifecycle of marine organisms and forcing species to extinction

Spread of diseaseTurns breeding grounds of mosquitoes, snails and flies, this leads to spread of disease

Affects the water table levelIt alters the natural water table

Decrease dissolved oxygen levelHydro power damages the surrounding environment and alters the quality of water by creating low

Decreased oxygen level

Conflict over the countryDams leads to serious problems between neighbouring countries and also between states

Geological damageLarge dams can cause Earth quakes

EFFECTS OF DAMS ON FOREST:

Areas of forest are cleared for the dam projects. It causes the loss of aquatic life. It leads to the loss of valuable plants and life of many animals.

EFFECTS OF DAMS ON TRIBAL PEOPLE:

The displacement of tribal people from one area to another area will occur. Tribal were mainly depended on the forest resources for their food and shelter. the constructional

projects will make them to lose their habitat. The change in their lifestyles and area will make them to lose their health.

CASE STUDIES

The Narmada sagar project has submerged 3.5 lakhs hectares of forest having teak and bamboo trees. The tehri dam project has submerged 1000 hectares of forest affecting the plane species. Aswan Dam in Egypt- altered the level of water table Hoovar Dam in USA-number of earth quakes and depressed the earth surface at its location

5. Explain the adverse effects of modern agriculture on soil and water sources

AgricultureAgriculture is the cultivation of plants, fungi and other life forms for food, fibre, bio-fuel and other products used to sustain human life.

Types of agricultureThe two types of agricultural system are1. Traditional agriculture2. Modern agriculture

Effects/impacts of on soil and water sourcesEffects/impacts of traditional agriculture

Deforestation Soil erosion Loss of nutrient

Traditional agriculture:Traditional agricultural tools involve physical works of a human and animals and farmers use manure from the livestock to fertilize the crops and some of the crop to feed the livestock-> domesticated animals

Modern agriculture:Modern agriculture involves machines and use of artificial fertilizer and nowadays using many modern techniques to yield many crops in small amount of land.

Impacts (or) Effects of modern agriculture

1. Impacts of Fertilizers

Micronutrient imbalanceA micro nutrient disorder may occur when the nutrient level is deficient or in excess. Most

commercially prepared fertilizers only include the macro nutrient like nitrogen ,phosphorous and potassium. This leads to micronutrient imbalance.(eg:zinc,iron,copper,iodine)

EutrophicationEutrophication is the enrichment of water by addition of nutrient like nitrogen and phosphorus. The

extra nutrients encourage the growth of algal blooms. These algae eventually die and decompose, removing the oxygen from the water and it cause the death of fish. This process is called eutrophication.

Blue baby syndromeBlue baby syndrome" can also be caused by methemoglobinemia. It is occurred due to high nitrate

contamination in groundwater resulting in decreased oxygen carrying capacity of haemoglobin in babies and leading to death

Ground water pollutionThe main environmental problem associated with fertilizer use in contamination of ground water with

nitrates and phosphates. High nitrate levels in drinking water are considered to be dangerous to human health

Soil acidity It occurs due to the production of organic acids by decomposing organic matter

2. Impacts of PesticidesA pesticide is any substance used to kill, repel, or control pests. It is used in homes, parks, schools,

building, forest and roads.

First generation pesticidesIt consist of organic and inorganic compounds

Organic compounds-Nicotine, Neem oilInorganic compounds-Arsenic, Lead, Mercury

Second generation pesticidesSecond generation Pesticides are synthetic compounds. It is used to kill the target pest. They produce

number of side effects. It also kills the other beneficial insects, birds, earthworms, fish around in the crop fieldExamples of second generation pesticides

Chlorinated hydrocarbons-DDT Organophosphates-Dimethane MalathionCarbamates - Carbayl

Producing new pest

Pesticides kill not only pests but it kill natural enemies of pests

Biomagnification

Biomagnification is the process in the ecosystem by which higher concentration of particular chemical such as DDT are reached in organisms that higher up in the food chain. Top food chain generally suffer greater harm from a persistent toxin or pollutant than those at lower levels.

Risk of cancer

Genetic damage, reproductive problems and cancer effects are the risk associated with pesticides

Reduction of beneficial species

Animals which are interacted with the target pest can also be affected by the chemical application. It results in loss of bio-diversity of an area and affect natural biological balances.

Desired qualities of an ideal pesticide

It must kill the target pest It should be non toxic to humans, mammals or fish. It should be safe and easy for use It should be biodegradable and UV degradable It should not produce new pest

6. What is overgrazing and changes caused by overgrazing?

Overgrazing

Overgrazing is a process of, “eating away the vegetation without giving it a chance to regenerate”.Effects of overgrazing/impacts

Overgrazing removes damager or reduces the amount of vegetation that is growing on an area. The soil temperature is increased which holds the roots loosely and allows soil erosion by winds and

rain. Decreases the water holding capacity of the soil. The ground cover would be depleted causing soil erosion. The native plants would be replaced by less favourable plants The food web in the area would be disrupted Droughts might occur due to the overheating of the land due to no ground cover. Permanent change in soil fertility.

7. Explain the various renewable resources/non - energy resources on earth(Or)

What are the renewable energy resources on earth?

RENEWABLE ENERGY RESOURCES

Definition: They are natural resources which can be regenerated continuously. It is used again and again

Examples: Solar energy = Solar cells, Solar heat collectors, Solar water heaterWind energy = Wind mills, Wind farmsOcean energy = Tidal energy, Ocean Thermal energy, Geothermal energy Biomass energy = Biogas, Bio fuel, Hydrogen fuel

Importance of renewable source of energy1. Abundant in nature2. Renewed within minimum effort and money3. Pollution free and eco-friendly

1. SOLAR ENERGY:

The Energy that we get directly from the sun is called solar energy. It is used for heating, lighting, cooling homes, generating electricity and for industrial process.

Solar energy conversionSolar energy originates from the thermonuclear fusion reactions taking place in the sun

Direct sunlight

Useful forms

Solar energy conversion occurs by 2 mechanisms

1. Thermal conversion2. Photo conversion

1. Thermal conversion

DefinitionThermal conversion is the absorption of thermal energy in the form of IR radiation. Solar thermal conversion systems use mirrors or reflectors to concentrate sunlight onto the container full of liquid. Sometimes water is used and other liquids are used. The liquids are heated up to high temperatures to produce stream. The stream is used to run a turbine. The turning motion of the turbine is used to create electricity.

Methods of thermal conversion1. Solar heat collectors2. Solar water heaters

1. Solar heat collectors

(a)Glazed flat plate collectorsGlazed flat plate collectors are insulated, weather proofed boxes that contain a dark absorber plate under one or more glass or plastic covers

(b)Unglazed flat-plate collectorsUnglazed flat-plate collectors typically used for solar pool heating have a dark absorber plate made of metal or polymer without a cover or enclosure

Uses Used in cold places where houses are kept in hot condition using solar heat collectors. It is used to collect heat for space heating,domestic hot water system

2. Solar water heaterSolar water heater is an insulated box inside of which is painted with black paint. Provided with a glass lid to receive and store solar heat. Inside the box it has black painted copper coil, which heats the cold water, then flows out into a storage tank. From the storage tank water is then supplied through pipes. There are two types of heating systems are active and passiveUses

Solar water heaters are used for converting the cold water into hot water Significance /uses of solar energy: They are noise & pollution free Solar water heaters, cookers require no fuels Solar cells can be used in remote & isolated forest & hilly regions

2. Photo conversion (or) Solar cells (or) photovoltaic cells (or) PV cells

Photo conversion involves conversion of light energy directly into electrical energyPhoto conversion can be made by photo galvanic cell or solar cell

Solar energy (Photo galvanic cell)Solar cells consist of a p-type semiconductor and n-type semi-conductor They are in close contact with each other.

When the solar rays fall on the top layer of p-type semi-conductor, the electrons from the valence band get promoted to the conduction band and cross the p-n junction into n-type semi-conductor.

Thus potential difference produced between two layers causes flow of electrons (ie., an electric current)

Uses Used in calculators Electronic watches Street lights Water pumps to run radios and TVs.

Solar BatteryLarge number of solar cells is connected in series to form a solar battery. Solar battery produces more electricity which is enough to run water pump, to run street-light etc

2) WIND ENERGY

DefinitionMoving air is called wind.Energy recovered from the force of the wind is called wind energy. The energy possessed by wind is because of its high speed. The wind energy is harnessed by making use of wind mills.

Methods of Harvesting wind energy

1. Wind Mills

The strike of wind on the blades of the wind mill rotates it continuously. The rotational motion of the blade drives machines like water pump, flour mills, electric generators

etc.

2. Wind farmsWind farm consists of large number of wind mills . The wind farms produce a large amount of electricity.

ConditionsThe minimum speed required for satisfactory working of a wind generator is 15 km/hr.

AdvantagesIt does not cause any air pollutionIt is very cheap.

Dis-advantagesIt produces unwanted soundWind farms gives hazards to bird life

3. Ocean energy

DefinitionOcean energy provides several forms of renewable energy and it is driven by different forcesIt can be obtained from ocean in two ways

i) From ocean waves or tidesii) From ocean heat

(i)From ocean tides or wavesTidal energy (or) Tidal power

Ocean tides, produced by gravitational forces of sun and moon, contain enormous amount of energy.The “high tide” and “low tide” refer to the rise and fall of water in the oceans. The tidal energy can be harnessed by constructing a tidal barrage. During high tide, the sea-water which flow into the reservoir of the barrage, rotates the turbine, which inturn produces electricity by rotating the generators

Uses of tidal energy:Do not require large areasPollution free energy sourceNo fuel is used & does not produce any wastes.

2. From Ocean heatThe heat stored in sea water can also be converted into electricity

Ocean thermal energy (OTE)The temperature difference between the surface level & deeper level of the oceans are used to generate

electricity. The energy available due to the difference in temperature of water is called ocean thermal energy.

ConditionThe temperature difference should be of 200C or more between surface water and deeper water.

ProcessThe warm surface water of ocean is used to boil a low boiling liquid like ammonia. The high vapour pressure thus produced turns the turbine of the generator and generates electricity.

UsesOTE is Continuous, renewable, pollution free, used to produce H2,

4. Geo-thermal Energy

DefinitionThe energy harnessed from high temperature & pressure present inside the earth is called geothermal energy.

1. Natural geysersIn some places, the hot water (or) steam comes from the ground through cracks naturally

2. Artificial geysersIn some places, we can drill a hole up to the hot region & make the hot water to rush out through

the pipe with very high pressure.Thus, the hot water (or) steam coming out from the natural (or) artificial geysers is allowed to rotate

the turbine of a generator to produce electricity.

Uses Power generation is higher than solar & wind energies Can be brought online quickly, Used for direct uses such as hot water bath, resorts, aquaculture, greenhouses. Pollution less

5. Biomass energyDefinition

Biomass is the organic matter, produced by plants or animals,Eg: Wood, crop residues, seeds, cattle dung, sewage, agricultural wastes.

1. BiogasMixture of methane, carbon-di-oxide and hydrogen sulphideIt contains about 65% of methane gas as a major constituent Biogas is obtained by the anaerobic fermentation of animal dung or plant wastes in the presence of

water.2. Bio fuels

Bio fuels are the fuels, obtained by the fermentation of biomass.Examples:(a)Ethanol = Easily produced from the sugarcane. Its calorific value is less than petrol,(b)Methanol = obtained from ethanol or sugar-containing plants.(c)Gasohol = Gasohol is a mixture of ethanol + gasoline.

3. Hydrogen FuelHydrogen can be produced by thermal dissociation or photolysis or electrolysis of water.

Advantages Eco-friendly Waste products are biodegradable No green house emission Cheaper fuel

Disadvantages Not sustainable

8. Explain the various conventional energy resources

Non renewable energy resourcesDefinition A non Renewable energy resource is an energy resource that is not replaced or it is replaced very slowly by natural process. They cannot be regenerated and cannot be used again and againExamples are coal, petroleum, CNG, LPG and Nuclear energy

1. CoalCoal is a solid fossil fuel formed in several stagesIt was subjected to intense heat and pressure over millions of years.It is formed out of organic matter deposited, decomposed and compressedCoal is the product of compression and heating organic matterCoal is a highly carbonaceous matter.

Various stages of coal

Wood → Peat (60% carbon) → Lignite (70% carbon) → Bituminous coal (80% Carbon) → Anthracite (90% carbon)

Advantages Affordable energy resource because of its stable price Easy to burn High energy upon combustion Inexpensive Abundant in nature Reliable energy resource

Disadvantages When coal is burnt it produces CO2 causes global warming Coal contains impurities like S and N; it produces toxic gases during burning.

2. Petroleum

Petroleum is naturally occurring liquid fuelIn Latin word petrarock and oleum oil or crude oilPetroleum or crude oil = hydrocarbons +small amount S, O, N.it is a dark viscous liquid found in deep earth crustCrude oil is the mixture of paraffinic, olefinic and aromatic hydro carbons

OccurrencePetroleum was formed by the decomposition of dead animals and buried under high temperature and pressure for million years

Fractional distillationHydrocarbons are separated by fractioning the crude oil.

3. Compressed Natural GasCNG is a natural gas (methane) compressed to high pressure about 1000 atmospheresA steel cylinder consist of 15kg of CNG contains about 20m3 of natural gas at 1 atmospheric pressure

1. Mixture of 50-90% methane and small amount of other hydrocarbons. 2. Its calorific value ranges from 12,000-14,000 k-cal/m3.

(i) Dry gas = the natural gas + lower hydrocarbons like methane and ethane, is called dry gas. (ii) Wet gas = natural gas + higher hydrocarbons like propane, butane along with methane is called wet

gas. Uses

Substitute for petrol and diesel Safer fuel Mixes better with air Less pollution Less CO emission

4. LPG (Liquefied Petroleum Gas)

LPG or refinery oil is obtained as a product during the cracking of heavy oils or from natural gasThe main constituents are

1. N-butane2. Iso-butane3. Butylenes4. Propane5. Little or no propylene

The petroleum gas, converted into liquid under high pressure is LPG

LPG is colourless and odourless gas.

During bottling some mercaptans is added, to detect leakage of LPG from the cylinder.

Uses

Domestic and industrial fuel LPG as a motor fuel

5. Nuclear Energy

Dr. H. Bhabha –father. India has 10 nuclear reactors, which produce 2% of India’s electricity.

Nuclear energy due to the conversion of some amount of mass into energyThe less mass is converted into Einstein equation

E=MC2

E EnergyMMassVvelocity of light

a) Nuclear FissionHeavier nucleus is split into lighter nuclei, on bombardment by fast moving neutrons, and a large

amount of energy is released.Example:

Fission of U235

When U235 nucleus is hit by a thermal neutron, it undergoes the following reaction with the release of 3 neutrons.

U92235 + n10 Ba13956 + Kr 9436+ 3n10 + Energy

Each of the above 3 neutrons strikes another U235 nucleus causing (3x3) 9 subsequent reactions. These 9 reactions further give rise to (3x9) 27 reactions. This process of propagation of the reaction by multiplication in threes at each fission is called chain

reaction.

Fission reaction of U235 is given below.

92U235 +0n1 → 36Kr92 + 56Ba141 + 3 0n1 + energy

Nuclear fission-chain reactionb) Nuclear fusion:

Lighter nucleuses are combined together at extremely high temperatures to form heavier nucleus and a large amount of energy is released.Example

Fusion of H21 .Two hydrogen-2 (Deuterium) atoms may fuse to form helium at 1 billion0C with the release of large amount of energy

1H2+1H2 → 3He2+0n1+energy

Nuclear power of India Tarapur(Maharashtra), Ranapratap Sagar

(Rajasthan) Kalpakkam (Tamilnadu) Narora (U.P).

9. Discuss the production of biogas. Mention its uses

DefinitionBiogas typically refers to a mixture of different gases produced by the breakdown of organic matter in

the absence of oxygen. Biogas is primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts

of hydrogen sulphide (H2S), moisture and siloxanes.

Composition of biogas

Production of biogasBiogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant

material, sewage, green waste or food waste.Biogas can be produced by anaerobic digestion with anaerobic bacteria, which digest material inside a

closed system or fermentation of biodegradable materials.

Steps in bio-gas productionproduction of biogas consist of following steps

1. Manure collection2. Anaerobic digestion3. Anaerobic digester4. Effluent storage 5. Sludge removal

Figure :Steps in Biogas productionManure collectionManure is easily collected on dairy farmsThe composition on manure varies according to feed rations and different farm management practicesThe amount of manure depend upon type,weight and number of animals and the feed rations

Anaerobic digesterThe main components are slurry preparation area,manure pump,loading methods and Effluent tankThe components of digester should

be arranged to minimize heat loss provide a simple flow path for material be automated as possible easily available for maintenance and repair

All materials are corrosion resistentEasily cleaningSlurry is supplied continously by batches

Anaerobic digestionAnaerobic digestion is a series of biological processes I which micro organisms break down biodegradable materials in the absence of oxygen

Acidogenic Bacteriaconverts sugars and amino acids into Carbon-di-oxide,Hydrogen,Ammonia and Organic acids

Acetogenic Bacteriaconverts organic acids into acetic acid along with Carbon-di-oxide,Hydrogen and Ammonia

Methanogensconverts these products to methane and Carbon-di-oxide

Optimum gas production occurs in two temperature Mesophilic bacteria - 35°C Thermophilic bacteria - 40°C-60°C

Figure: Production of Biogas

Effluent storage

The effluent flows through an overflow pipe into a covered manure pitThe organic content of the processed manure is reduced and stabilizedThe effluent is colourless, Odourless liquid which does not attract rodents and fliesThe effluents are highly nitrogen contentIt act as a excellent fertilizer for plants

Sludge removal

The sludge is collected at the bottom of the digester tank, it must removed regularly to reduce the accumulation

The sludge is removed from the digester through the sludge gates built in the bottom of the digester which is operated by hydraulic valves

When the gates are opened, the sludge flows into the auger channel and auger conveys the sludge to storage pit

Uses of biogas As a fuel for boilers and heaters As a fuel providing heat for Chilling/Refrigeration As a fuel for engines, turbines and fuel cells Methane reduces the impacts of global warming Improves nutrient properties of soil Treatment of waste reduce water, air pollution, bad odors and pathogens

ECOSAN program ECOLOGICAL SANITATION (ECOSAN) is executed by Indian NGO Navsarjan

Trust supported by SDC Ecological sanitation is an approach which is characterized by a desire to safely "close

the loop" (mainly for the nutrients and organic matter) between sanitation and agriculture.

Ecosan systems safely recycle excreta resources (plant nutrients and organic matter) to crop production in such a way that the use of non-renewable resources is minimized.

VK–NARDEP

Vivekananda Kendra - Natural Resources Development Project (VK–NARDEP), India

This is a biogas plant constructed from bricks and concrete shallow in pit for small farmers

Cattle manure is blended with water and added to digester tank, displacing solid residue at the outlet. Decomposition of the manure produces biogas which is tapped off and used for cooking.

Between 1986 and 2006, 2,000 biogas plants installed in southern Tamil Nadu, directly benefiting around 12,000 people.

By 2009, a total of 2,500 biogas plants had been installed including 100 of the VINCAP design benefitting some 15,600 people.

10. Discuss the following (i) Land resource(ii) Land degradation and factors responsible for land degradation(iii) Soil erosion (iv)Desertification and its ill effects(v)man induced landslides

(i)LAND RESOURCES

Land as a resourceLand is the most important and a valuable resource for mankind as it provides food,

fibre, wood, medicine and other biological materials need for food. soil is the mixture of inorganic (rocks and minerals) and organic materials (dead animals and plants). top soil is classified as renewable resources, because it is continuously regenerated by natural process at a very slow rate. but, if the rate of erosion is faster than the rate of renewal, then the soil becomes a non-renewable resource.

Uses of land resources1. Land provides food, wood, minerals, etc., for us.2. Land nurtures the plants and animals that provide our food and shelter.3. Land is used as water shed or reservoir.4. Land act as a dust bin for most of the wastes, created by the modern society.5. Land is used for construction of buildings, industries.

(ii) LAND DEGRADATION AND FACTORS RESPONSIBLE FOR LAND DEGRADATION

Land degradation is the process of deterioration of soil or loss of fertility of the soil.

Harmful effects of land (soil) degradation1. The soil texture and structure are deteriorated.2. Loss of fertility, due to loss of invaluable nutrients.3. Increase in water logging, salinity, alkalinity, and acidity problems.4. Loss of economic social and biodiversity.

Causes of (or factors affecting) land degradation

1. Population: as population increases, more land is needed for producing food, fibre and fuel wood.

2. Urbanisation: the increased urbanisation due to population growth reduces the extent of agricultural land.

3. Fertilizers and Pesticides: increased applications of fertilizers and pesticides are needed to increase farm output in the new lands, which again leads to pollution of land and water and soil degradation

4. Damage of top soil: increase in food production generally leads to damage of top soil through nutrient depletion

5. Water logging, soil erosion, salination, and contamination of the soil with industrial wastes all cause land degradation.

(iii) SOIL EROSION Soil erosion is the process of removal of top layer of the soil from one place to

another by natural agents like sun, wind, water or by man.Types of soil erosionTwo types of soilerosion

1. Natural or Geographical soilerosionIt is caused due to wind,water etc

2. Artificial or manmade soil erosionErosion caused due to human activities such as deforestation,cultivating

lands,road construction and building dams etc.

Factors causing soil erosionSlope

Steeper the slope, the greater the erosionIncreased velocity of water flowGreater the concentration of flooding water

Soil structureGrouping or arrangement of soil particlesOver cultivationOrganic material is the main source of soil organism both plant and animal. It

influences the infiltration capacity of the soil therefore reducing runoffWind

Soil is easily blown away by the force of wind which carry the fine particles of soilRain or Precipitation

Heavy rain falls, the impact of the drop causes the soil to erode easilyFlooding

It cause soil to erode, water carries the soil away

Soil type Sandy soil type are more easily eroded than the clay type soils

Ploughing

Ploughing of fields makes soil to erode easilyOvergrazing

Cattle, sheep, goat and other animals take away the vegetation cover and expose the

bare soil

Effects of Soil ErosionDue to loss of top soil, the following effects take place

Decrease soil fertilityTop layer of soil contains most of the organic matter and nutrientsLoss of this soil reducing soil fertility and affecting its structure badly

Damage to the cropsSoil erosion by wind cause sandy storms which damage the crops

FloodSoil eroded by water gets deposited on river beds, thus increase their level and causes

floods

DesertificationSoil eroded also leads to desertification. It refers to increase of desert areas

Prevention of soil erosion

TerracingTerracing is an alternative management practice for water conservation and erosion

controlIt decreases the slope length and reduces damage by surface water runoff

Contour FarmingContour Farming is very effective practise for soil erosionEach furrow acts as a reservoir to receive and retain runoff water

Alley cropping or strip croppingAlley cropping or agro forestry: it involves planting crops in strips or alleys between

rows of trees of shrubs that can provide fruits and fuel wood. Even when the crop is harvested, the soil will not be eroded because trees and shrubs

still remain on the soil and hold the soil particles.

Wind breaks or shelter beltsThe trees are planted in long rows along the boundary of cultivated lands, which

block retaining soil moisture, supply of some wood for fuel and provide habitats for birds.They are commonly planted around the edges of fields on farms

(iv)DESERTIFICATION

Progressive destruction or degradation of a grass land or Arid land into a desert is

known as desertification.

Such actions include Overgrazing, repeated burning, intensive farming and stripping

of vegetation for firewood

Causes of Desertification

1. Deforestation

This directly leads to lower rainfall and higher temperature

2. Climate change

Formation of desert, failure of monsoon and frequent drought

3. Mining

It causes deforestation, which may ultimately result in desertification. It cause

destruction of water table and surface water. The habitat of lot of organisms is destroyed by

mining

4. Pollution

Excessive use of fertilizers and pesticides and disposal of toxic water into the land

also leads to desertification

5. over cultivation

Growing too many crops, year after year on the same place of land damages the soil

structure and reduces the land fertility

6. Overgrazing

cattle, sheep, goat and other animals take away the vegetation cover and expose the

bare soil

7. Poor irrigation

This makes ground too salty

8. Drought

Damage the vegetation

Consequences of vegetation

Economic loss

Desertification cause drop in biological productivity

Major threat to bio diversity

Affect the lives of wild species, domestic animals, agricultural crops and people

Deterioration of land resources

Land get destructed continuously

Decrease plant nutrient in the soil

Reduction of plant cover which is caused due to desertification causes reduction in the

quantity of plant nutrient in the soil

Steps to reduce Desertification

1. Reduce Overgrazing and deforestation

2. Limit human activities such as destructive forms of planting, irrigation and mining that

leave soil barren

3. Plant more trees and grasses to hold water

4. Plant leguminous plant that extract nitrogen from the air and fix it into the soil to restore

fertility

(v)LANDSLIDES

Landslide or Landslip is a geological phenomenon. The rapid downward and outward

movement of sliding of a mass of earth and rock

The action of gravity is the primary driving force for a landslideUnderwater landslide can cause Tsunami

During construction of roads and monitoring activities huge portions of fragile mountainous areas are cut and thrown into adjacent areas and streams. The land masses weaken the already fragile mountain slopes and lead to landslides called man induced landslides.

Causes of landslidesNatural causes

Elevation of pore water pressureVibrations caused by earth quakesVolcanic eruption

Human causesRemoval of vegetationInterference or changes in natural drainageModification of slopes by construction of roads, railways, buildingsOverloading slopesMining and quarrying activitiesVibrations from heavy traffic, blastingExcavation or displacement of rocks

Effects of landslidesLandslides cause property damage, injury and deathNegative economic effectsWater availability, quantity and quality can be affected by land slidesLoss of habitat and biodiversity

Prevention of land slidesBy slope vegetationDiverting Debri pathways

Landslide warning signs

Areas that is generally prone to landslides hazardsOn existing old landslidesOn or at the base of slopesIn or at the base of minor drainage hollowsAt the base or top of an old fill slopeAt the base or top of a steep cut slope

Areas that are typically considered safe from land slidesOn hard, on-joined bedrock that has not moved in the pastFlat-lying areas away from sudden changes in slope angle

(vi)DEFORESTATIONDeforestation is the destruction of forest resources due to natural and man-made

activities.

Causes of Deforestation:

1. Increase in demand of wood products:Forests are the valuable assets for our country. They provide habitat for plants and

animals. The people who need wood for their domestic purpose make deforestation.

2. due to fuel requirements:To meet the fuel requirements, the rural people are cutting down the trees.

3. due to developmental projects:The developmental projects across the various parts of the country also cause a major

change in the forest.

4. due to mining operations:Mining reduces the area of forest.

5. Farming:Due to farming across various parts of our country, the cultivation of plants will differ

and also due to the demand, deforestation will take place.

6. Increase in population:Due to the increase in population, forests are converted into rural areas which destroy

the living plants and animals.

7. Forest fires:Due to the increase in temperature, the forest fires will happen. this results in destroy

of plants and animals.

Effects:

1. Shifting of people:Due to deforestation, migration of people from one area to another to meet their requirements.

2. Loss of biodiversity:Deforestation on a huge scale results in loss in biodiversity and on a natural global

scale is known to cause the extinction of many species.

3. On nutrient cycles:Disturb the hydrological cycle and hence makes the land to lose its fertility.

4. Changes in climate:The temperature will increase and loss in humidity will occur.

5. Increase in floods and landslides:Floods and landslides occur due to the destruction of trees.

6. Loss of wood:By cutting the trees, the wood resources will become scarce.

7. Loss in economy:Destroying medicinal plant leads to the loss in country economy.

8. Affects global warming:Deforestation will bring greater effects in climate.The emission of carbon dioxide will

result in the global warming.

9. Loss of forest products:The products of forest will greatly depleted due to the sudden destruction of tress.

10. on pollution:Trees are the major pollution controllers. When deforestation occurs, the air pollution

will not be controlled.

11. Soil degradation:Deforestation makes the land infertile.

Preventive measures:1. Plant more trees2. Shifting cultivation must be reduced3. Awareness programmes must be organized for afforestation4. Cattle grazing must be controlled5. Develop alternative renewable energy sources to meet the energy requirement of remote villages6. Forest fires must be controlled.7. The developmental projects should not disturb the forest environment

11. Explain the role of individual in conservation of natural resources

Role of individual in conservation of natural resources:

1. Conservation of energy Turn off lights, fans and other appliances when not in use. Dry the clothes in sun instead of drier Use solar cooker for cooking food on sunny days and will cut down LPG expenses. Grow trees and climbers near the houses and get a cool breeze and shade. This will

cut off electricity charges on coolers and A/C Ride bicycle or just walk instead of using your car or scooter. Always use pressure cooker.

2. Conservation of water: Use minimum water for all domestic purpose Check for water leaks in pipes & toilets & repair them properly Reuse the soapy water after washing clothes for washing courtyards, drive ways etc. Use drip irrigation to improve irrigation efficiency & reduce evaporation The waste water from kitchen, bath tub can be used for watering the plants Build rainwater harvesting system in your home

3. Conservation of soil: Grow plants, trees & grass which bind the soil & prevent its erosion Don’t irrigate the plants using strong flow of water, as it will wash off the top soil Soil erosion can be prevented by the use of sprinkling irrigation Use green manure in the garden, which will protect the soil Use mixed cropping, so that specific soil nutrients will not get depleted While constructing the house don’t uproot the trees

4. Conservation of food resources: Eat minimum amount of food, avoid over eating. Don’t waste the food; instead give it to someone before getting spoiled. Cook only required amount of food Don’t cook food unnecessarily Don’t store large amounts of food grains & protect them from insects.

5. Conservation of forest: Use non-timber products Plant more trees & protect them Grassing, fishing must be controlled Minimize the use of papers & fuel wood Avoid developmental work like dam, road, and construction in forest areas

11. Explain in detail Environmental Biochemistry

Biochemistry deals with chemical changes brought about by living organisms

PROTEINS Proteins are naturally occurring polypeptides of molecular weight greater than 5000 Proteins are naturally occurring in human body. They are building blocks of tissue. Proteins are polymer chains made of amino acids linked together by peptide bonds. During human digestion, proteins are broken down in the stomach to smaller

polypeptide chains via hydrochloric acid

Structure of proteinsMost proteins fold into unique 3-dimensional structure

Primary structureThe primary structure of protein is an amino acid sequence. A protein is a polyamide

in which the amino acids occur in the polymer chain

Secondary structure Secondary structure is made up of hydrogen bonds. The most common examples are alpha helix, beta sheet Turns. The helical structure is maintained by hydrogen bonds from –NH groups on

one part of chain to the c=0 groups on or above the coil. The R groups of Amino acids pointed out from coil Another way is called BETA- pleated sheet. It is zigzag pattern of amino acids

extend above or below the pleats

Tertiary structureThe tertiary structure controls the basic function of the protein. Alpha, beta and random coil structures interact themselves to form the higher order

structures. This type of structure involves the formation of covalent bond. It is a biologically active structure due to R groups of amino acid chain interactions.

Quaternary structureTwo or more protein structures associate to make a largest structure as a single unit.

Functions of proteins

Repair and maintenanceProtein is termed as building block of body it is used for maintenance of body tissue, including development and repair. Hair, skin, eyes, muscles and organs are all made from protein children need more protein per pound of body weight than adults

EnergyProtein as a major source of energy. If you consume more protein than you need for body tissue maintenance and other

necessary functions. Your body will use it for energy. other energy resources -carbohydrates, the protein ,fat

HormonesProtein is involved in creation of some hormones. Insulin a small protein - regulates blood sugar . Secretin -protein hormone-assists in digestive process by stimulating pancreas and

intenstine to create digestive juices

Transportation and storage of moleculeProtein is a major element in transportation of some molecules. Example hemoglobin is a protein that transports oxygen throughout the body. Protein is also used to store certain molecules. Ferritin is an example of protein that combines with iron for storage in the liver

AntibodiesProtein forms antibodies that help prevent infection, illness and disease. These proteins identify and assist in destroying antigens such as bacteria and viruses