EVS 1 _merged.pdf

INTRODUCTION “Environmental studies deal with every issue that affects living organisms. It is essentially a multidisciplinary approach that brings about an appreciation of our natural world and human impact on its integrity.” The word environment is derived from the French word “Environ” meaning...

INTRODUCTION “Environmental studies deal with every issue that affects living organisms. It is essentially a multidisciplinary approach that brings about an appreciation of our natural world and human impact on its integrity.” The word environment is derived from the French word “Environ” meaning “Surroundings” i.e. everything around us is environment. World Environment Day is celebrated on 5th June every year. The Stockholm Conference: United Nations International Conference on Human Environment, was held at Stockholm, Sweden, from 5th June to 14th June 1972. It was attended by representativesof 114 nations. For the first time respectivegovernments at the highest level came together to take note of how mankind had misused our environment of which we are an integral part. 150 Action plans and 20 principles were approved to protect the delicate balance of ecosystems and to preserve them for the coming generation. The conference adopted the motto “Only one earth” for the entire humanity. The conference declared 5th June as world environment day Environment provides us with a basic life support system through air, water and food. We cannot continue to survive without protecting the earth's environmental resources. Basic terms related to the environment: 1. Environment : It includes all aspects ofthe world around us in which humans, animals and plants live. 2. Ecology : The science that studies the relationships between living and non-living things. It studies the structure and function of nature. 3. Environmental Science : It is the systematic and scientific study of our environment. It integrates knowledge from the pure sciences, ecology, engineering, management, social sciences and other aspects. 4. Environment Education : A subject concerned with learning on all environmental issues. It has a wider coverage than environmental science or ecology. It also includes the social aspects of the environment. 5. Environmental Degradation : It is the damage caused to the environment due to various human activities which harm our surrounding. For example: Deforestation, pollution of water, air, soil etc. 6. Environmental Conservation: It includesways in which to protect nature and control the damage caused to our natural environment. For example, when we prevent the killing of wildlife, or we turn a barren land into a forest, we are conserving the environment. The environment consists of four segments. These are 1. Atmosphere 2. Hydrosphere 3. Lithosphere 4. Biosphere 1. Atmosphere About 99% of the total earths atmospheric mass is concentrated in the first 30 km above Earth's surface. Based on characteristics such as temperature and composition, the earth's atmosphere can be divisible into following layers –Troposphere, Stratosphere, Ionosphere, Exosphere. Layers of Atmosphere; 1) Troposphere : Troposphere is at about 12 km from Earth's surface. The lowest layer from the surface of the earth is known as" Troposphere ". The temperature decreasesaccording to the height at this level. The drop of temperature rate at every 160 m height is about 100C. The temperature differs at different heights and at different layers. Although this layer is smaller than the other layers, it is important as regards the weight of the air and it covers 80% of the atmospheric air. Other elements of the air are vapor, water molecules, dust and microscopic organisms are found in thislayer. This layer is very important and useful for the life of living beings. in whichrain, wind, storm, hail, snow, clouds etc. exist. Tropopause the layer that separates troposphere and stratosphere layers is called as tropopause which is at 2 to 3 km above the troposphere. It is umbrella like coat of air which has stable air. Rain, wind,lightning, clouds, storm, etc., do not exist inthis layer. The tropopause has a width of 1.5 km, and temperature of this layer is about - 53° C. It also contains high amount dry ozone. 2) Stratosphere : Stratosphere is a layer between tropopause and stratopause. The height of this layer keeps changing according to seasons. Temperatures remain constant for certain height of the layer. But beyond 32 Km of height, the temperature increases. This layer is called 'Isothermal Zone'. The heat from the sun is absorbed inthis layer hence temperature is retained. The extension of this layer is much higher in the summer than in the winter. The air inthis part of the atmosphere is sparse. Humidity, dust, clouds, etc. are not exactly the same. Ozonosphere is a layer of Ozone whichcover at a height of about 20 to 35 km from the surface of the earth. When the ultravioletradiation from sunlight come in contact with oxygen, they are processed and ozone (O3) gas is produced. Ozone layer absorbs the harmful ultraviolet rays radiated from Sun, hence the temperature of Ozone layer increases. This layer protects life on Earth. Hence ozone layer is called "Protective umbrella of earth ". Today, due to increasing pollution, the layer of ozone is becoming weak, that results in increase in global temperature, (Global Warming). This has become a serious matter in terms of survivalof living organisms. 3) Ionosphere: Ionosphere is a layer found beyond the stratosphere, around 360 to 400km from the surface of the earth, which is until the end of atmosphere. It extends from104 to 112 km from the surface of the earth.The radio waves travel from this layer to the Earth, because of which we can listen to the radio. Only 1% of the air is present in this layer of the total atmospheric air. The mesosphere extends upto 85 km from stratosphere. The top of the mesosphere, called mesopause, is the coldest part ofEarth's atmosphere with temperatures avaranging about -1300 F (-900C). Jets and ballons don't go high enough in this layer. 4) Exosphere : Exosphere extends from 500 to 750 km from the surface of the earth. At a height ofabout 490 km radio waves of a temperatureof 17000 C has been detected through rocketand radio waves. This layer predominantly contains neutral atoms of Oxygen, Helium and Hydrogen. At a height of about 2000 km, the Neutral atoms have an effect calleda magnetic circle. 2. Hydrosphere: Hydrosphere covers more than 71% of the earth’s surface either as oceans (salt water) or as fresh water. Hydrosphere includes (both surface and underground water) sea, rivers, oceans, lakes, ponds, streams and wetlands. 3. Lithosphere: It includes the Earth’s crust and upper mantle. It contains the fossil fuels and minerals and the soil chemicals (nutrients) needed to support plant life. 4. Biosphere: The portion of earth where living (biotic) organisms are found and interact with one another and with their non-living (abiotic) environment. This zone of life includes, plants, animals, and their habitat. Scope and Importance Environment is not a single subject; it is an integration of several subjects that includes both science as well as social science. To understand all the aspects of our environment, we need to know about life sciences, chemistry, physics, geography, resource management, economics, and engineering and social science,population, issues of poverty, resource use and allied issues. Thus the scope of environment education is extremely wide and covers some aspects of nearly every major discipline. If we study the natural history of the areas in which we live, we would see that our surroundings were originally a natural landscape such as forest, river, mountain,desert, marine environment or a combination ofthese elements. Most of us live on landscapes that have been profoundly modified by human beings into villages towns or cities. We get our food supply from surrounding villages which inturn, are dependent on natural landscapes such as forests, grasslands and rivers for resources. The industrial development and intensive agricultural practices that provide the goods for our increasing consumer oriented society uses up a large amount of natural resources. Consequently, these will get exhausted in the near future. If we continue to extract them. There will be nothing left for the next generations. Rapid economic growth and unplanned development has inevitably led to environmentaldegradation. The environment affects us in many ways due to weather changes and quality of air and water. We in turn affect the natural environmentoften negatively. We cut trees or throw away ourgarbage, which has an adverse effect on the environment. In the industrialized era that we live intoday, every component of our environment such as air, water or food are impacted by industrial activities, infrastructure development, population explosion and pollution. ENVIRONMENT STUDIES: IMPORTANCE Importance of Environment Studies: The environment studies enlighten us, about the importance of protection and conservation of our indiscriminate release of pollution into the environment. At present a great number of environment issues, have grown in size and complexity day by day, threatening the survival of mankind on earth. We study about these issues besides and effective suggestions in the Environment Studies. Environment studies have become significant for the following reasons: 1. Environment Issues Being of International Importance It has been well recognised that environment issues like global warming and ozone depletion, acid rain, marine pollution and biodiversity are not merely national issues but are global issues and hence must be tackled with international efforts and cooperation. 2. Problems Cropped in The Wake of Development Development, in its wake gave birth to Urbanization, Industrial Growth, Transportation Systems, Agriculture and Housing etc. However, it has become phased out in the developed world. The North, to cleanse their own environment has, fact fully, managed to move ‘dirty’ factories of South. When the West developed, it did so perhaps in ignorance of the environmental impact of its activities. Evidently such a path is neither practicable nor desirable, even if developing world follows that. 3. Explosively Increase in Pollution World census reflects that one in every seven persons in this planted lives in India. Evidently with 16 per cent of the world's population and only 2.4 per cent of its land area, there is a heavy pressure on the natural resources including land. Agricultural experts have recognized soils health problems like deficiency of micronutrients and organic matter, soil salinity and damage of soil structure. 4. Need for An Alternative Solution It is essential, specially for developing countries to find alternative paths to an alternative goal. We need a goal as under: (1) A goal, which ultimately is the true goal of development an environmentally sound and sustainable development. (2) A goal common to all citizens of our earth. (3) A goal distant from the developing world in the manner it is from the over- consuming wasteful societies of the “developed” world.  5. Need To Save Humanity From Extinction It is incumbent upon us to save the humanity from exinction. Consequent to our activities constricting the environment and depleting the biosphere, in the name of development. 6. Need For Wise Planning of Development Our survival and sustenance depend. Resources withdraw, processing and use of the product have all to by synchronised with the ecological cycles in any plan of development our actions should be planned ecologically for the sustenance of the environment and development. NEED FOR PUBLIC AWARENESS It is essential to make the public aware of the formidable consequences of the Environmental Degradation, if not retorted and reformative measures undertaken, would result in the extinction of life. We are facing various environmental challenges. It is essential to get the country acquainted with these challenges so that their acts may be eco-friendly. Some of these challenges are as under: 1. Growing Population A population of over thousands of millions is growing at 2.11 per cent every year. Over 17 million people are added each year. It puts considerable pressure on its natural resources and reduces the gains of development. Hence, the greatest challenge before us is to limit the population growth. Although population control does automatically lead to development, yet the development leads to a decrease in population growth rates. For this development of the women is essential. 2. Poverty India has often been described a rich land with poor people. The poverty and environmental degradation have a nexus between them. The vast majority of our people are directly dependent on the nature resources of the country for their basic needs of food, fuel shelter and fodder. About 40% of our people are still below the poverty line. Environment degradation has adversely affected the poor who depend upon the resources of their immediate surroundings. Thus, the challenge of poverty and the challenge environment degradation are two facets of the same challenge. The population growth is essentially a function of poverty. Because, to the very poor, every child is an earner and helper and global concerns have little relevance for him. 3. Agricultural Growth The people must be acquainted with the methods to sustain and increase agricultural growth with damaging the environment. High yielding varities have caused soil salinity and damage to physical structure of soil. 4. Need to Ground water It is essential of rationalizing the use of groundwater. Factors like community wastes, industrial effluents and chemical fertilizers and pesticides have polluted our surface water and affected quality of the groundwater. It is essential to restore the water quality of our rivers and other water bodies as lakes is an important challenge. It so finding our suitable strategies for consecration of water, provision of safe drinking water and keeping water bodies clean which are difficult challenges is essential. 5. Development And Forests  Forests serve catchments for the rivers. With increasing demand of water, plan to harness the mighty river through large irrigation projects were made. Certainly, these would submerge forests; displace local people, damage flora and fauna. As such, the dams on the river Narmada, Bhagirathi and elsewhere have become areas of political and scientific debate. Forests in India have been shrinking for several centuries owing to pressures of agriculture and other uses. Vast areas that were once green, stand today as wastelands. These areas are to be brought back under vegetative cover. The tribal communities inhabiting forests respects the trees and birds and animal that gives them sustenance. We must recognize the role of these people in restoring and conserving forests. The modern knowledge and skills of the forest deptt. should be integrated with the traditional knowledge and experience of the local communities. The strategies for the joint management of forests should be evolved in a well planned way. 6. Degradation of Land At present out of the total 329 mha of land, only 266 mha possess any potential for production. Of this, 143 mha is agricultural land nearly and 85 suffers from varying degrees of soil degradation. Of the remaining 123 mha, 40 are completely unproductive. The remaining 83 mha is classified as forest land, of which over half is denuded to various degrees. Nearly 406 million head of livestock have to be supported on 13 mha, or less than 4 per cent of the land classified as pasture land, most of which is overgrazed. Thus, our of 226 mha, about 175 mha or 66 per cent is degraded to varying degrees. Water and wind erosion causes further degradation of almost 150 mha This degradation is to be avoided. 7. Reorientation of Institutions The people should be roused to orient institutions, attitudes and infrastructures, to suit conditions and needs today. The change has to be brought in keeping in view India’s traditions for resources use managements and education etc. Change should be brought in education, in attitudes, in administrative procedures and in institutions. Because it affects way people view technology resources and development. 8. Reduction of Genetic Diversity Proper measures to conserve genetic diversity need to be taken. At present most wild genetic stocks have been disappearing from nature. Wilding including the Asiatic Lion are facing problem of loss of genetic diversity. The protected areas network like sanctuaries, national parks, biosphere reserves are isolating populations. So, they are decreasing changes of one group breeding with another. Remedial steps are to be taken to check decreasing genetic diversity. 9. Evil Consequences of Urbanization Nearly 27 per cent Indians live in urban areas. Urbanization and industrialization has given birth to a great number of environmental problem that need urgent attention. Over 30 percent of urban Indians live in slums. Out of India’s 3,245 towns and cities, only 21 have partial or full sewerage and treatment facilities. Hence, coping with rapid urbanization is a major challenge. 10. Air and water Population Majority of our industrial plants are using outdated and population technologies and makeshift facilities devoid of any provision of treating their wastes. A great number of cities and industrial areas that have been identified as the worst in terms of air and water pollution. Acts are enforced in the country, but their implement is not so easy. The reason is their implementation needs great resources, technical expertise, political and social will. Again the people are to be made aware of these rules. Their support is indispensable to implement these rules. 1.2 Sustainable Development India is an emerging economy with diverse communities, cultures and religions.It covers a vast geographical area and long coastline.Topographically the Indian subcontinent is diverse. It has 10 distinctive biogeographic zones. India has been experiencing rapid growthin population which has led to socio-economic inequity and rampant uncontrolled growth patterns which has led to environmental degradation. All this would obviously have long term negative impacts on the environment and its consequences would be felt particularly by the socio-economically challenged groups and our future generations. To combat the problems of unsustainable growth patterns, post Stockholm Conference of 1972, India adopted the concept of Sustainable Development (SD). In 1992, during the United Nations Conference on Environment and Development (UNCED); India became a part ofthe 187 countries pledging their commitment towards achieving Sustainable Development by signing the Rio Declaration. In 1992 during the Earth Summit of the UNCED, the role of education in achieving Sustainable Development was a major concern (Agenda 21). Education has been considered as one of the basic requirement and tool towards achieving Sustainable Development. Educating people from all walks of life would serve the dual purpose of creating awareness about environment conservation and protection. Thus safeguarding the environment would help to combat and reduce the socio- economic inequityby empowering people through education. The Government of India later recommended the Ministry of Human Resource Development to integrate environmentalconcerns, issues and awareness in education at all levels. In its 57th meeting in December 2002 (UNESCO, 2002), the UN General Assembly proclaimed the UN Decade of Education forSustainable Development (DESD), 2005- 2015,emphasized that ‘education is an indispensableelement for achieving sustainable development.Education is often considered to be done in classrooms. According to UNESCO (2004),Education for Sustainable Development (ESD)is formal education, but it extends to dailysocial and professional life. ESD can makeeducation ‘participatory’. This enhances theproblem solving capacities of young peoplethrough processes which enable collaboration and dialogue. Concept of sustainable development Sustainable Development refers todevelopment which can meet the needs of the present generation without compromising on theability of the future generations to meet their own needs (Brundtland Report, 1987). There are three aims of sustainabledevelopment 1. Economic - to attain balanced growth 2. Environmental - to preserve theenvironment 3. Social- to include all human communitiesto access all resources. Social The concept of ‘‘needs’’ refers to essential needs of human beings. Millions of people today do not have adequate food, proper house, clean drinking water or basic education. The definition suggests that such essential needs of all people must be met with. But at the sametime the pattern of development has to be such that future generations would also be able to meet their own needs from the resources without destroying or degrading nature. This may include water resource, productivity of various ecosystems, quality of air etc. Development conventionally means enhancing economic well-being and wealth. Well-being of an individual or family and community depends on several factors apart from income levels. Development is more than economic growth. The development achieved inthe short term may not continue over time and isunsustainable in the longer term. Concept of sustainable consumption Development is largely based on the use ofresources. Therefore, a change in the pattern of development requires a change in the pattern of resource use. The pattern of sustainable consumption relates to use of both renewable and non-renewable resources. For renewable resources the use of a resource should not exceed the capacity of the environment to replenishingthe resources. Non-renewable resources should be used with care as they can be totally used up.The natural available resources are shrinkingbecause consumption levels are so high. Current consumption patterns are responsible for increasing pollution which damages our environment. In the recent past consumerism has becomea part of our daily life. There is also inequality in the way, rich and underprivileged groupsin the society use resources. Our excessive resource use creates unsurmountable amountsof waste. All this requires changes to be made inour lifestyles to prevent the further degradation of our environment. Each one of us is creating a large environment foot print in our resource base. We all need to reduce our environmental foot print and create positive impacts to conserveour environmental resources for the future. This is now referred to as environmental handprint. Inspite of India’s rapid population growth, industrialization and consumerism our country still includes a wealth of Natural Resources which requires urgent conservation measures. To understand the proper structure and functions of various kinds of ecosystem, it is very essential to understand the scope ofecology. The word ecology is derived from two Greek words i.e. “Oikos” meaning house and “ology” means to study. Thus, ecology is the study of organisms in their natural home i.e. habitat. It is generally defined as the study of plants and animals in reciprocal relationship with their environment. Structure and function of Ecosystems: In nature several communities of organismslive together and interact with each other as wellas with their physical environment as an ecological unit. An ecosystem is a functional unit of nature encompassing complex interactionbetween its biotic (living) and abiotic (non- living) components. For example- aquatic systems such as a pond, lake, river, estuary, ocean. The terrestrial ecosystems include forest, grassland, agricultural field, desert etc. The structure of ecosystem is includes two kinds of components. (a) Abiotic components (b) Biotic components (a) Abiotic components (Nonliving): The abiotic component can be grouped into following three categories: - (i) Physical factors: Sun light, temperature, rainfall, humidity and pressure. They sustain and limit the growth of organisms in an ecosystem. (ii) Inorganic substances: Carbon dioxide, nitrogen, oxygen, phosphorus, sulphur,water, rock, soil and other minerals. (iii) Organic compounds: Carbohydrates, proteins, lipids. They are the building blocks of living systems and therefore, make a link between the biotic and abiotic components. (b) Biotic components (Living) (i) Producers: The green plants manufacture food for the entire ecosystem through the process of photosynthesis. Green plants arecalled autotrophs, as they absorb water andnutrients from the soil, carbon dioxide fromthe air, and capture solar energy for this process. (ii) Consumers: They are called heterotrophs and they consume food synthesized by the autotrophs. Based on food preferences theycan be grouped into three broad categories. a) Herbivores feed directly on plants (e.g.cow, deer and rabbit etc.) b) Carnivores are animals which eat other animals. (eg. lion, cat, dog etc.) c) Omnivores organisms feed upon both plantsand animals (e.g. human beings, pigs and crows). (iii) Decomposers: Also called saprotrophs. These are mostly bacteria and fungi that feed on dead organic matter of plants and animals by secreting enzymes outside theirbody on the decaying matter. They play a very important role in recycling of nutrients.They are also called detritivoours or detritusfeeders. Functions of ecosystems: Ecosystems are complex dynamic entities whichinclude abiotic and biotic components. They perform various functions. These are:- (i) Energy flow through food chain (ii) Nutrient cycling (biogeochemicalcycles) (iii) Ecological succession or ecosystemdevelopment Ponds, lakes, marshlands, grasslands, deserts and forests are examples of natural ecosystems. Many of you have seen a grassland, a garden and an agricultural field in your neighborhood. These are examples of man made ecosystems. 1. Food chain: The transfer of food energy from the source (Producers / green plants) to consumers forms a food chain. Green plants in the food chain occupy the first trophic level (i.e. producer).The herbivoresthat eat the plants occupy second trophic level (i.e. primary consumers). The carnivores that eat the herbivores occupy third trophic level (i.e. secondary consumers) and occasionally even a fourth trophic level (i.e. tertiary consumer). In nature three types of food chains havebeen distinguished namely grazing food chain, parasitic food chain and detritus food chain. I) Grazing food chain: This food chain startsfrom green plants, goes through herbivores and terminates in carnivores. The photosynthetic organisms, synthesise their food from inorganic elements in the presence of sunlight, hence they are called producers. The producers are eaten by herbivorous animals, thus herbivorous animals are called primary consumers. Primary consumers orherbivores are eaten by secondary consumers called carnivores. Thus this typeof food chain depends on autotrophs asprimary producer. II) Parasitic food chain: This food chain goesfrom large organisms to smaller oneswithout killing the host organism. For e.g. large number of lice live on herbivore as ectoparasites. III) Detritus food chain: The food chain startsfrom dead organic matter of decaying plants and/or animals bodies, microorganisms and then to detritus feeding organisms (detritivores or saprovores) and their predators which is known as detritus food chain. e.g. Dead and drying leaves in forest are broken into smaller pieces by soilanimals such as beetles, ants, earth warms on which fungi and bacteria act to produce soil nutrients. some of these soil animals are used food by secondary consumers likebirds, frogs and lizards. This type of interrelationship interlinks the individuals of the whole community. In this way multiple food chains become interlinked forming a food web. The food web maintains the stability of theecosystem. Energy flow in ecosystem : Energy can be defined as the capacity to perform work. The solar radiation is the primarysource of energy for all organisms which passesthrough the different trophic levels. Organisms that can fix energy from inorganic sources into organic molecules are called autotrophs.Organisms that cannot obtain energy from abiotic sources but depend on energy-rich organic molecules which is synthesized by autotrophs are called heterotrophs. Those organisms that obtain energy from living Food Web: Many food chains exist in an ecosystem, but these food chains are not independent of each other. The producers are eaten by variety of insects, birds, mammals and fishes. These first order consumers are eaten by predators. In grassland ecosystem, grass is eaten by herbivores such as hare which will be eatenby snake, which will be eaten by an eagle organisms are called consumer and those that obtain energy from dead organisms are called decomposers. The movement of energy in an ecosystem is termed as the energy flow in nature. i) The producers absorb and convert solarenergy into plant material. ii) The energy converted into biomass is usedby consumers. iii) The total input of energy in form of food isused for day to day activities and biomass. iv) The loss of energy occur throughrespiration, heat, excretion. v) The gross net production. About 23% of incoming solar energy isabsorbed in the atmosphere by water vapours, dust and ozone, and 48% passes through the atmosphere and is absorbed by the surface. Thusabout 71 % of the total incoming solar energy isabsorbed by the earth system. However plants do not absorbs all incoming sunlight and do notconvert all harvested energy into biomass, which results in an overall photosyntheticefficiency of 3 to 6 % of total solar radiation. It means very small amount of sunlight reaching the earth’s atmosphere is used in photosynthesis.The plant synthesize food in the form of carbohydrates i.e. is a form of chemical energy. This chemical energy of carbohydrates is used as a food for herbivores. In the food chain or food web, there is transfer of both the matter and energy in the living world. The transfer of energy is never 100 %. The green plants trap solar energy and convert it into chemical energy, they are the producers. They use some amount of energy for their own life processes. Therefore, only a small portion of theenergy trapped by the producers is available to primary consumers. Animals move from place to place, so they require more energy. Therefore they transfer less amount of energy to the next trophic level. At every trophic level, a considerable amount of energy is lost to the surroundings in the form of heat. The amount of energy availableto the next higher level is only 10%. Even decomposition of organic mattercarried out by microbes is responsible for releaseof heat energy. Thus most of the solar energy trapped by the green plants goes to the atmosphere in the form of heat. But, this heat energy never returns to the sun. Energy transfer is therefore never in the reverse direction. Ecological pyramids Ecological pyramids are the graphic representations of trophic levels in an ecosystem.The producers make the base of the pyramidand the subsequent tiers of the pyramid represent herbivore, carnivore and top carnivore. The pyramids are of three types. (1) Pyramid of number: This represents the number of organismsat each trophic level. For example in a grassland the number of grasses is more than the number of herbivores that feed on them and the number of herbivores is more than the number of carnivores. In some instances the pyramid of number may be inverted, i.e herbivores are more than primary producers as you may observe that many caterpillars and insects feed on a single tree. (1) Pyramid of biomass: This represents the biomass at each trophic level. Standing biomass is the amount ofthe living matter at any given time. It is expressedas gm/unit area or kilo cal/unit area. In most of the terrestrial ecosystems the pyramid of biomass is upright. However, in case of aquatic ecosystems the pyramid of biomass may be inverted e.g. in a pond, phytoplankton are the main producers, they have very short life cyclesand a rapid turn over rate (i.e. they are rapidly replaced by new plants). Therefore, their total biomass at any given time is less than the biomass of herbivores supported by them. (2) Pyramid of energy : This pyramid represents the total amountof energy at each trophic level. Energy is expressed in terms of kcal/unit area /unit time. Energy pyramids is never inverted. All the living organisms of an ecosystem are interdependent through food chains and food webs. Removal of any single species of thecommunity causes ecological change. In the food chain the producers can be eaten by several primary consumers (h erbivoves). These multiple herbivoves are eaten by only a fewer species of carnivares. In every ecosystem the quantum of producers is the largest followed by primary consumers and only a few second order consumers. This isbecause at every step in the trophic chain energy is lost in day to day activities. 2.2 Types of ecosystems Ecosystems are broadly classified as follows: (I) Natural ecosystems (II) Man-made ecosystems (I) Natural ecosystems Natural ecosystem is totally dependent onsolar radiation e.g. forests, grasslands, oceans, lakes, rivers and deserts. They provide food, fuel, fodder and medicines. Example: Pond Ecosystem: A pond is an example of natural ecosystem. It is convenient to study its basic structure and functions. It works on solar energy and maintainsits biotic community depending on the seasons. If you collect a glass full of pond water or a scoop full of mud from bottom of the pond, it consists of a mixture of plants, animals, microorganisms, inorganic and organic materials. (II) Man-made ecosystems: 1) It is a system which is influenced by significant human interactions between living and non- living components. 2) They do not possess self-regulating mechanisms. 3) The cycling of nutrients is negligible. 4) The inputs are provided by human efforts. Example Aquarium Land as a Resource: Land is a very valuable resource that provides food, fiber, medicine, wood and other biological materials needed for mankind. Land is a resource generating area on which people depend. If land is utilized carefully, it can be considered a renewable resource. Land is a finite and valuable resource uponwhich we depend for our food, fiber and fuel wood. Prof. HIMANSHU G. FYBSc (EVS) To understand the proper structure and functions of various kinds of ecosystem, it is very essential to understand the scope of ecology. The word ecology is derived from two Greek words i.e. “Oikos” meaning house and “ology” means to study. Thus, ecology is the study of organisms in their natural home i.e. habitat. It is generally defined as the study of plants and animals in reciprocal relationship with their environment. Structure and function of Ecosystems: In nature several communities of organisms live together and interact with each other as well as with their physical environment as an ecological unit. An ecosystem is a functional unit of nature encompassing complex interaction between its biotic (living) and abiotic (non- living) components. For example- aquatic systems such as a pond, lake, river, estuary, ocean. The terrestrial ecosystems include forest, grassland, agricultural field, desert etc. The structure of ecosystem is includes two kinds of components. (a) Abiotic components (b) Biotic components (a) Abiotic components (Nonliving): Prof. HIMANSHU G. FYBSc (EVS) The abiotic component can be grouped into following three categories: - (i) Physical factors: Sun light, temperature, rainfall, humidity and pressure. They sustain and limit the growth of organisms in an ecosystem. (ii) Inorganic substances: Carbon dioxide, nitrogen, oxygen, phosphorus, sulphur, water, rock, soil and other minerals. (iii) Organic compounds: Carbohydrates, proteins, lipids. They are the building blocks of living systems and therefore, make a link between the biotic and abiotic components. (b) Biotic components (Living) (i) Producers: The green plants manufacture food for the entire ecosystem through the process of photosynthesis. Green plants are called autotrophs, as they absorb water and nutrients from the soil, carbon dioxide from the air, and capture solar energy for this process. (ii) Consumers: They are called heterotrophs and they consume food synthesized by the autotrophs. Based on food preferences they can be grouped into three broad categories. a) Herbivores feed directly on plants (e.g. cow, deer and rabbit etc.) b) Carnivores are animals which eat other animals. (eg. lion, cat, dog etc.) c) Omnivores organisms feed upon both plants and animals (e.g. human beings, pigs and crows). (iii) Decomposers: Also called saprotrophs. These are mostly bacteria and fungi that feed on dead organic matter of plants and animals by secreting enzymes outside their body on the decaying matter. They play a very important role in recycling of nutrients. They are also called detritivoours or detritus feeders. Functions of ecosystems: Ecosystems are complex dynamic entities which include abiotic and biotic components. They perform various functions. These are: - (i) Energy flow through food chain (ii) Nutrient cycling (biogeochemical cycles) (iii) Ecological succession or ecosystem development (productivity to decomposition) Ponds, lakes, marshlands, grasslands, deserts and forests are examples of natural ecosystems. Many of you have seen a grassland, a garden and an agricultural field in your neighborhood. These are examples of manmade ecosystems. Prof. HIMANSHU G. FYBSc (EVS) Types of Ecosystem An ecosystem can be as small as an oasis in a desert, or as big as an ocean, spanning thousands of miles. There are two types of ecosystem: Terrestrial Ecosystem Aquatic Ecosystem Terrestrial Ecosystem Terrestrial ecosystems are exclusively land-based ecosystems. There are different types of terrestrial ecosystems distributed around various geological zones. They are as follows: 1. Forest Ecosystem 2. Grassland Ecosystem 3. Tundra Ecosystem 4. Desert Ecosystem Forest Ecosystem A forest ecosystem consists of several plants, particularly trees, animals and microorganisms that live in coordination with the abiotic factors of the environment. Forests help in maintaining the temperature of the earth and are the major carbon sink. Grassland Ecosystem In a grassland ecosystem, the vegetation is dominated by grasses and herbs. Temperate grasslands and tropical or savanna grasslands are examples of grassland ecosystems. Tundra Ecosystem Tundra ecosystems are devoid of trees and are found in cold climates or where rainfall is scarce. These are covered with snow for most of the year. Tundra type of ecosystem is found in the Arctic or mountain tops. Desert Ecosystem Deserts are found throughout the world. These are regions with little rainfall and scarce vegetation. The days are hot, and the nights are cold. Aquatic Ecosystem Aquatic ecosystems are ecosystems present in a body of water. These can be further divided into two types, namely: 1. Freshwater Ecosystem 2. Marine Ecosystem Freshwater Ecosystem The freshwater ecosystem is an aquatic ecosystem that includes lakes, ponds, rivers, streams and wetlands. These have no salt content in contrast with the marine ecosystem. a) Lentic: stagnant waterbodies like pond b) Lotic: moving waterbodies like river Marine Ecosystem The marine ecosystem includes seas and oceans. These have a more substantial salt content and greater biodiversity in comparison to the freshwater ecosystem. Prof. HIMANSHU G. FYBSc (EVS) 1. Food chain: The transfer of food energy from the source (Producers / green plants) to consumers forms a food chain. Green plants in the food chain occupy the first trophic level (i.e. producer). The herbivores that eat the plants occupy second trophic level (i.e. primary consumers). The carnivores that eat the herbivores occupy third trophic level (i.e. secondary consumers) and occasionally even a fourth trophic level (i.e. tertiary consumer). In nature three types of food chains have been distinguished namely grazing food chain, parasitic food chain and detritus food chain. I) Grazing food chain: This food chain starts from green plants, goes through herbivores and terminates in carnivores. The photosynthetic organisms, synthesize their food from inorganic elements in the presence of sunlight, hence they are called producers. The producers are eaten by herbivorous animals, thus herbivorous animals are called primary consumers. Primary consumers or herbivores are eaten by secondary consumers called carnivores. Thus this type of food chain depends on autotrophs as primary producer. II) Parasitic food chain: This food chain goes from large organisms to smaller ones without killing the host organism. For e.g. large number of lice live on herbivore as ectoparasites. III) Detritus food chain: The food chain starts from dead organic matter of decaying plants and/or animals bodies, microorganisms and then to detritus feeding organisms (detritivores or saprovores) and their predators which is known as detritus food chain. e.g. Dead and drying leaves in forest are broken into smaller pieces by soil animals such as beetles, ants, earth warms on which fungi and bacteria act to produce soil nutrients. some of these soil animals are used food by secondary consumers like birds, frogs and lizards. This type of interrelationship interlinks the individuals of the whole community. In this way multiple food chains become interlinked forming a food web. The food web maintains the stability of the ecosystem. Prof. HIMANSHU G. FYBSc (EVS) Energy flow in ecosystem: Energy can be defined as the capacity to perform work. The solar radiation is the primary source of energy for all organisms which passes through the different trophic levels. Organisms that can fix energy from inorganic sources into organic molecules are called autotrophs. Organisms that cannot obtain energy from abiotic sources but depend on energy-rich organic molecules which is synthesized by autotrophs are called heterotrophs. Those organisms that obtain energy from living Food Web: Many food chains exist in an ecosystem, but these food chains are not independent of each other. The producers are eaten by variety of insects, birds, mammals and fishes. These first order consumers are eaten by predators. In grassland ecosystem, grass is eaten by herbivores such as hare which will be eaten by snake, which will be eaten by an eagle organisms are called consumer and those that obtain energy from dead organisms are called decomposers. The movement of energy in an ecosystem is termed as the energy flow in nature. i) The producers absorb and convert solar energy into plant material. ii) The energy converted into biomass is used by consumers. iii) The total input of energy in form of food is used for day to day activities and biomass. iv) The loss of energy occurs through respiration, heat, excretion. v) The gross net production. About 23% of incoming solar energy is absorbed in the atmosphere by water vapors, dust and ozone, and 48% passes through the atmosphere and is absorbed by the surface. Thus about 71 % of the total incoming solar energy is absorbed by the earth system. However, plants do not absorb all incoming sunlight and do not convert all harvested energy into biomass, which results in an overall photosynthetic efficiency of 3 to 6 % of total solar radiation. It means very small amount of sunlight reaching the earth’s atmosphere is used in photosynthesis. The plant synthesize food in the form of carbohydrates i.e. is a form of chemical energy. This chemical energy of carbohydrates is used as a food for herbivores. In the food chain or food web, there is transfer of both the matter and energy in the living world. The transfer of energy is never 100 %. The green plants trap solar energy and convert it into chemical energy, they are the producers. They use some amount of energy for their own life processes. Therefore, only a small portion of the energy trapped by the producers is available to primary consumers. Animals move from place to place, so they require more energy. Therefore, they transfer less amount of energy to the next trophic level. At every trophic level, a considerable amount of energy is lost to the surroundings in the form of heat. The amount of energy available to the next higher level is only 10%. Even decomposition of organic matter carried out by microbes is responsible for release of heat energy. Thus most of the solar energy trapped by the green plants goes to the atmosphere in the form of heat. But, this heat energy never returns to the sun. Energy transfer is therefore never in the reverse direction. Prof. HIMANSHU G. FYBSc (EVS) Ecological pyramids Ecological pyramids are the graphic representations of trophic levels in an ecosystem. The producers make the base of the pyramid and the subsequent tiers of the pyramid represent herbivore, carnivore and top carnivore. The pyramids are of three types. 1. Pyramid of number: This represents the number of organisms at each trophic level. For example, in a grassland the number of grasses is more than the number of herbivores that feed on them and the number of herbivores is more than the number of carnivores. In some instances, the pyramid of number may be inverted, i.e. herbivores are more than primary producers as you may observe that many caterpillars and insects feed on a single tree. Prof. HIMANSHU G. FYBSc (EVS) 2. Pyramid of biomass: This represents the biomass at each trophic level. Standing biomass is the amount of the living matter at any given time. It is expressed as gm/unit area or kilo cal/unit area. In most of the terrestrial ecosystems the pyramid of biomass is upright. However, in case of aquatic ecosystems the pyramid of biomass may be inverted e.g. in a pond, phytoplankton are the main producers, they have very short life cycles and a rapid turnover rate (i.e. they are rapidly replaced by new plants). Therefore, their total biomass at any given time is less than the biomass of herbivores supported by them. 3. Pyramid of energy: This pyramid represents the total amount of energy at each trophic level. Energy is expressed in terms of kcal/unit area /unit time. Energy pyramids is never inverted. All the living organisms of an ecosystem are interdependent through food chains and food webs. Removal of any single species of the community causes ecological change. In the food chain the producers can be eaten by several primary consumers (herbivores). These multiple herbivores are eaten by only a fewer species of carnivores. In every ecosystem the quantum of producers is the largest followed by primary consumers and only a few second order consumers. This is because at every step in the trophic chain energy is lost in day to day activities. Prof. HIMANSHU G. FYBSc (EVS) Types of ecosystems Ecosystems are broadly classified as follows: (I) Natural ecosystems (II) Man-made ecosystems (I) Natural ecosystems Natural ecosystem is totally dependent on solar radiation e.g. forests, grasslands, oceans, lakes, rivers and deserts. They provide food, fuel, fodder and medicines. Example: Pond Ecosystem: A pond is an example of natural ecosystem. It is convenient to study its basic structure and functions. It works on solar energy and maintains its biotic community depending on the seasons. If you collect a glass full of pond water or a scoop full of mud from bottom of the pond, it consists of a mixture of plants, animals, microorganisms, inorganic and organic materials. (II) Man-made ecosystems: 1) It is a system which is influenced by significant human interactions between living and non- living components. 2) They do not possess self-regulating mechanisms. 3) The cycling of nutrients is negligible. 4) The inputs are provided by human efforts. Example Aquarium. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) BIODIVERSITY Today most of us live in a socially and technologically evolved society where our exploitive potential and knowledge of nature has increased academically. The problem is that our contact with it has diminished morally. It may have diminished to such an extent as to be dangerous to us and to the nature itself. Biodiversity is the vast array of all the species of plants, animals, insects and the microorganisms inhabiting the earth either in the aquatic or the terrestrial habitats. The human civilization depends directly or indirectly upon this biodiversity for their very basic needs of survival–food, fodder, fuel, fertilizer, timber, liquor, rubber, leather, medicines and several raw materials. This diversity’s the condition for the long-term sustainability of the environment, continuity of life on earth and the maintenance of its integrity. Biodiversity is defined by the Convention on biological diversity as "the variability of living beings of all origins including, among others, aquatic ecosystems and the ecological complexes they are a part of this includes diversity within species and the diversity of ecosystems" There are three hierarchical levels. (a) Genetic diversity: This is the variability that is present in the individuals of a species due to differences in individual’s geneticmakeup. It refers to variation of genes within species. Differences could be in entire genes or in structure of chromosomes. Geneticdiversity enables a population to adapt to the environment. It is also responsible for speciation. Some variations are easy to see, such as; size, colours, taste and flavor. For example, varieties of rice and wheat. Deliberate manipulation of genes by humans within a species produces newvarieties of crops and new breeds of domestic animals. (b) Species diversity: It is the variability in the species richnesswithin a specified area (habitat). It refers to the variety of species in agiven region. It is largely the result of natural evolutionary process. (c) Ecosystem diversity : It is the variety of ecosystems that are present on the earth. some of them include forest, grassland, pond, river, marine ecosystems etc. This variety in ecosystems is formed because of different climatic conditions and topographical features which are present on the earth. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) HOTSPOTS OF BIODIVERSITY Areas with rich biodiversity and exhibiting high levels of endemism, which are under immediate threat of species extinction and habitat destruction, are recognized on priority basis worldwide for conservation practices and are known as hot spots. 12 hot spots identified world over represent 14% of world’s plant species in only 0.2% of its -total land surface. 12 mega diversity nations (Mexico, Columbia, Brazil, Peru, Ecuador, Madagascar, Indonesia. Malaysia. India, China and Australia) contain 60-70 % of the world’s biodiversity. Out of the total hot spots worldwide two lies in India. These are represented by North-eastern Himalayas (Khasi jaintia hills and the lower Himalayan slopes embracing areas of Arunachal Pradesh, Assam, Meghalaya, Nagaland and Tripura) and Western Ghats region in the south. These fall under heavy rainfall zones. The rain forests of the Western Ghats and the eastern Himalayas consist of very dense and lofty trees with a multitude of species occurring in the same area. Hundreds of species of trees can be identified in a hectare of land besides mosses, ferns, epiphytes, orchids, lianas and vines, herbs shrubs and fungi that make up this. region the most diverse habitat. Giant trees stretch up towards the sun. Buttress roots, anchored within the soil, support the smooth straight trunks, which rise 30 mts. or more before branching out. The spreading crowns effectively block out most of the light from the light from the ground beneath. Dipterocarpus sp. predominates in these forests and this type of vegetation is often called Dipterocarpus forests. 1. North-east Himalayas From the dense evergreen and semi-evergreen vegetation of the foothills in the Eastern. Himalaya, the character of vegetation changes at altitudes of 1525 m to 1830 m. Qaks, magnolias, laurels and birches covered with moss and ferns replace the sal, silk-cotton trees and giant bamboos of the foothills. At about 2745 m to 3660 m one enters the coniferous forest of pine, fir yew and junipers. There is undergrowth of scrubby Rhododendrons and dwarfs bamboos. Due to high humidity and much higher rainfall, lichens, mosses, orchids and other epiphytes cover the tree trunks. The animal life in the temperate region is different from the western Himalaya and is characterized by the presence of Indo Chinese fauna. The red panda, hog badgers, ferret badgers, crestless porcupines are typical species of this area. Three kinds of goat antelopes also occur in the eastern Himalaya and are relatives of the European chamois. Goral is a smaller goat antelope found throughout the tract on rugged grassy slopes and on rocky grounds near the conifers forests. 2. Western Ghats The Western Ghats and the central belt lying to the west of it, is a region of very high rainfall and is characterized by evergreen vegetation, its flora and fauna being a kin to the evergreen rain forest of north-eastern India. Among the macaques the lion tailed (Macaca silenus) is one of the world’s most endangered primates, surviving in the evergreen forests of the Western Ghats of south India, its total population is estimated to be about 800 only. In the langur group, the nilgiri ‘Iangur’ (Presbvtis johni) Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) is a multihabitat species occurring in addition to the shoals, in the temperate evergreen forests above 1700 m altitude in the Western Ghats. A number of climbing animals have evolved gliding mechanisms and are particularly characteristic of these forests. Among these are the flying squirrels. The other characteristic species of the Western Ghats are the Nilgiri mongoose, the stripnecked mongoose, the malabar civet and the spiny mouse. The flora and fauna of these evergreen regions have not been fully explored. Being a store house of a large variety of plants and animals, these forests represent one of the richest gene pool resources of flora and fauna in the country. Though a large number of such forests have not been destroyed for various plantation crops like rubber, cocoa, coffee etc., whatever virgin forests remain have to be specially protected as in the Silent Valley of Kerala or the rich orchid belt of the north-eastern Himalayas in Arunachal Pradesh and Sikkim. ENDANGERED AND ENDEMIC SPECIES OF INDIA The Forest administration in India is more than 100 years old. Efforts to identify plant species as a part of wildlife and to recognize the importance for providing special protection to endangered plant species have so far been negligible. The extinction of certain attractive animals stimulated efforts to protect fauna, but no special heed was given to flora. The word ‘Wildlife’ had till recently been considered synonymous with animal life and consequently, conservations and naturalists have their attention only to conservation of animal species. It was only in the year 1968 at an International Conference (UNESCO 1968) that the problem of conservation of flora and fauna was appreciated and several recommendations were made urging the International Biological Programme (IBP),.the International Union for Conservation of Nature and Natural resources (IUCN) and various international and national organizations to initiate studies in to the problems involved, particularly the problem of protecting and preserving wild fauna and flora in their natural habitat/ecosystems establishing nature reserves. Later at the 10th General Meeting of the IUCN, the Survival Service Commission reviewed the status of endangered species of plants and their habitats. The recent promulgations of the United States Endangered Species Act (1973), the UK Wild Creatures and Wild Plants Act. (I975), development of international conventions on conservations (Wetlands Convention) and the setting up of Biological Records Centre of the Nature Conservancy, UK, and threatened plants, orchids, cycads tree wide awakening of the need for the conservations, preservation and protection of floras of the world. According to the Volume 5 of Red Data Book on angiosperms started by the Survival Service Commission of the IUCN in the year 1970 (Melville, 1970), it is estimated that out of the total of three lakes (0.3 million) species of plants in the world, over 20,000 were in the category of either endangered or vulnerable and threatened with extinction by the year 2000 A.D.The following categories of rare species have been recognized by the IUCN, mainly based on (i) present distribution, (ii) decline in number of time, (iii) abundance and quality of natural habitats, and (iv) biology and potential value of the species. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Endangered (E) Species in danger of extinction and whose survival is unlikely if the casual factors continue operating, included are species whose numbers have been reduced to a critical level or whose habitats have been so drastically reduced that they are deemed to be in immediate danger of extinction. Vulnerable (V) Species believed likely to move into the endangered category in the near future if the casual factors continue operating. Included are species, of which most or all the populations are decreasing because of over-exploitation, extensive destruction of habitat or other environmental, disturbance species with populations that have been seriously depleted and whose ultimate security is not yet assured; and species with populations that are still abundant but are under threat from serious adverse factors throughout their range. Rare (R) Species with, small world populations that are not at present endangered or vulnerable, but are at risk. These species are usually localized within restricted geographical areas or habitats or thinly scattered over a more extensive range. Threatened (T) Threatened is used in the conservation context for species which are in one of the categorizer Endangered, Vulnerable and Rare. Some species are marked as threatened where it is known that they are Endangered, Vulnerable or Rare, but there is known that they are Endangered, Vulnerable or Rare, but there is not enough information to say which of these three categories is appropriate. Out of Danger (O) Species formerly included in one of the above categories, but which are now considered relatively secure because effective conservation measures have been taken or the previous threat to their survival has been removed. Indeterminate (I) Species that are suspected of belonging to one of the first three categories, but for which insufficient information is currently available. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Threats to Biodiversity The wild variety of species on the earth arevital to keep the world’s many ecosystems healthy, balanced and thriving. There are several major causes of biodiversity loss. 1. Fragmentation and Habitat loss Habitat degradation overexploitation of resources, agricultural conversion and urbanization are the factors contributing to loss of biodiversity. The consequent fragmentation of habitat results in smallisolated patches of land which cannot maintain populations of species in the longterm. When large habitats are broken up into small fragments due to various human activities, those mammals and birds which require large territories are decline and may become extinct. Certain animals which migrate long distances are badly affected, leading to a population decline. 2. Over exploitation Over- hunting, over-fishing and over- harvesting contribute greatly to the loss of biodiversity. 3. Invasive species The introduction of non-native species into an ecosystem can threaten endemicwildlife. When alien species are introducedunintentionally or deliberately for whateverpurpose, some of them become invasive and cause a decline in the population or extinction of indigenous species. Threats posed to our native species by invasive weed species include Partheniun, Lantana and water Hyacinth. Tilapia fish introducedfrom South America has reduced the population of local fish species. 4. Pollution Air pollution and acid rain destroy forests. Water pollution kills fish and otheraquatic plants and animals. Toxic and hazardous substances that are drained into water sources kill aquatic life. Oil spills killcoastal birds and aquatic plant life and other marine animals. Plastic trash affects wildlife. Pollution is a big threat to biodiversity. 5. Climate Change Climate change is already having animpact on biodiversity, and is projected to become a progressively more significant threat in the coming decades. Loss of Arctic sea ice threatens biodiversity across an entire biome and beyond. The related pressure of ocean acidification, resultingfrom higher concentration of carbon dioxide in the atmosphere, is alreadythreaten our ecosystem. In addition to warming temperatures, increased frequency of extreme weather events, storms and changing patterns of rainfall and repeated drought well have a significant impact on biodiversity. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Conservation of both plants and animals is very important to decrease the number of extinct species in biodiversity. Conservation means taking care of different species and prohibiting them from extinction by providing them special care and protection. Two types of conservation are possible based on the place where the conservation is done- ex-situ and in-situ. Ex-situ Conservation Ex-situ conservation is one of the key goals of the Botanical Survey of India is conservation (BSI). It is a type of ‘off-site’ conservation policy that entails a set of strategies that relate the transfer of an objective species under threat from its natural environment to a considerably safer haven, such as a Botanical Garden, Seed Bank, Zoological Garden, or Gene Bank, among other places. The primary purpose of this strategy is to provide appropriate support for conservation initiatives by ensuring the survival of vanishing and threatened species as well as their associated genetic diversity. In-situ Conservation In-situ conservation refers to the preservation of animals in its native environment. Using a network of protected areas, such as biosphere reserves, national parks, and animal sanctuaries, this strategy aims to safeguard the natural habitat. These protected areas for the preservation of wildlife occupy 4.7 percent of the Indian landmass. Examples The nation’s parks: Human activities like forestry, grazing, or gardening are not permitted because the region is set aside for the conservation of animals. India has 104 national parks totalling 40,501 square kilometres. Ex-situ and in-situ conservation importance Conservation of wildlife, both ex-situ and in-situ is important for the ecosystem. Wildlife provides balance to nature and the natural process. It is important to conserve both flora and fauna of a specific area. Conservation also saves a huge number of species from extinction of both plants and animals. It also saves a wide range of plants having medicinal properties which would help in the invention of different medicines. Both ex-situ and in-situ conservation have their own importance. Ex-situ conservation is necessary for conservation of species whose natural habitat gets destroyed for some reasons. This also preserves genes, spores and gametes as well which is necessary for performing further studies. In case of in-situ conservation, it is important as both habitats as well as the animals are saved by this type. Difference between Ex-situ and in-situ conservation Methods of biodiversity conservation Conservation efforts can be grouped into the following two categories: 1. In-situ (on-site) conservation includes the protection of plants and animals within their natural habitats. Protected Areas on land or in the sea which is dedicated to protect and maintain biodiversity is done through our national parks and sanctuaries. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) 2. Ex-situ (off-site) conservation of plants and animals is done outside their natural habitats. These include botanical gardens, zoos, gene banks, seed bank, tissue culture and In-situ Conservation Ex-situ Conservation This represents the process of conserving all This includes the process of conservation of living species in their natural climate and living species in man-made artificial habitat habitat, mainly wild and endangered species which is similar to their natural habitat. to avoid the transportation. In this case, both habitat and living Only living organisms are protected here organisms are protected It is appropriate only when large numbers of It is appropriate in case of limited number of members are found. members Examples include national parks, biosphere Examples consist of Aquariums, reserves, and wildlife sanctuaries. cryopreservation, botanical gardens, gene banks and so on. cryopreservation. 1. In-situ Conservation i) Protection of habitat: The main strategy for conservation of species is the protection of habitats in representative ecosystems. Currently, India has 104 National Parks, 551 Wildlife Sanctuaries, 18 Biosphere Reserves, 50 Tiger Reserves and 32 Elephant Reserves. 27 wetlands, 30 mangrove areas and four coral reef areas have been identified for intensive conservation and management purposes by the Ministry of Environment, Forests and climate change, Govt. of India. National Parks and Wildlife Sanctuaries: Many National Parks and Wildlife Sanctuaries have been established to preserve wildlife in their natural environment. The Jim Corbett Tiger Reserve- Uttaranchal, Kanha National Park, Madhya Pradesh, Bandhavgarh National Park- Madhya Pradesh, Ranthambhor National Park- Rajashtan, Gir National Park- Gujarat etc. Some of the main protective areas in India are; i. Kaziranga National Park (Assam) – One- horned rhinoceros ii. Manas National Park (Assam) – Wild buffaloes iii. Gir National Park (Gujarat) – Lions, chital, sambar, wild bears iv. Kolleru National Park (Andhra Pradesh) – Pelicans and marine birds v. Dachigam National Park (Jammu and Kashmir) – Kashmir stag, wild goats, and sheep. vi. Bandipur National Park (Karnataka) –Indian bison, elephants, langurs, Tiger vii. Periyar National Park (Kerala) – Elephants,barking deer, sambar viii. Kanha National Park (Madhya Pradesh) – Tiger, leopards, wild dogs, barasingha. ix. Keoledeo National Park (Rajasthan) –ducks, herons, flemingo, pelicans. x. Jim Corbett National Park (Uttaranchal) – Tigers, barking deer, sambar, bear, rhesus monkey. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Biosphere Reserves The concept of Biosphere Reserves (BR)was launched in 1975 as a part of UNESCO’s Man and Biosphere Programme (MAB), dealing with the conservation of ecosystems and the genetic material they contain. A Biosphere Reserve consists of core, buffer and transition zones. (a) The core zone is the fully protected natural area of the Biosphere Reserve which is least disturbed by human activities. It is a legally protected ecosystem in which entryis not allowed except with permission for some special purpose. Destructive sampling for scientific investigations is prohibited. (b) The buffer zone surrounds the core zone and is managed so that some resources canbe used by local people and promotes research and educational activities. (c) The transition zone is the outermost part ofthe Biosphere Reserve. It is an area where active co-operation between the reserve management and the local people. Such as settlements, agiculture, forestry, recreation and other economic activities are in harmony with the conservation goals. Thereare 553 Biosphere Reserves located in 107 countries in the world. The main functions of the biosphere reservesare: Conservation: Long term conservation ofrepresentative landscapes and different types of ecosystems along with all theirspecies and genetic resources. Development: Encourage traditionalresource use and promote economic development which is culturally, socially and ecologically sustainable. Scientific research, monitoring and education: Support conservation research, monitoring, education and information exchange related to local, national and global environmental and conservation issues. ii) Species-Oriented Projects: Several species have been identified that need a concentrated and specifically directed effort to prevent extinction. 1. Project Tiger – This has been success in conservation of the tiger its prey and its habitat. Tigers which were once abundant in Indianforests declined drastically from an estimate of 40,000 at the turn of nineteenth century to 1200by 1970. This led to initiating Project Tiger in 1973, with the objective of conserving and rescuing this species from extinction. A total ban was imposed on hunting of tigers and trading in tiger products at the national and international levels. Elaborate management plans are made for each of the tiger reserves fortiger habitat improvement and anti -poaching measures to safeguard our national animal. 2. Project Elephant Project Elephant was launched in February, 1992 to assist states having free ranging populations of wild elephants toensure long-term survival of identified viable populations of elephants in their natural habitats. The project is being implemented in several states. Some of them are; Andhra Pradesh, Arunachal Pradesh, Assam, Jharkhand, Kerala, Karnataka, Odisha, Tamil Naidu, West Bengal etc. Recently elephants have started migrating into Maharashtra in the Kokan region (Sawantwadi) creating man-elephant Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) conflict in the area. 2. Ex-situ Conservation i) Botanical Gardens, Zoos: To complementin-situ conservation efforts, ex-situ conservationis being undertaken through setting up botanicalgardens, zoos, medicinal plant parks, etc. by various agencies. The Indian Botanical Garden in Howrah (West Bengal) is over 200 years old.Other important botanical gardens are in Ooty, Bangalore and Lucknow. Number of zoos have been developed in thecountry. They have played an important role in the conservation of endangered animal species such as the Manipur Thamin deer (Cerus eldi eldi) and Red panda (Ailurus fulgens) of Assam.Notable successful examples of captive breedingis that of Gangetic gharial (Gavialis gangeticus). The main objectives of botanical gardens are – Ex-situ conservation and propagation of important threatened plant species. Serve as a Centre for Conservation, Research and training, Build public awareness through education on plant diversity and need for their conservation. ii) Gene Banks: Ex-situ collection andpreservation of genetic resources is done through gene banks and seed banks. The National Bureau of Plant Genetic Resources (NBPGR), New Delhi preserves seeds of wild relatives of crop plants as well as cultivated varieties; the NationalBureau of Animal Genetic Resources (NBAGR) at Karnal, Haryana maintains the genetic material for domesticated animals and the National Bureau of Fish Genetic Resources (NBFGR), Lucknow forfishes. iii) Cryopreservation: This method isparticularly useful for conserving crops through vegetative propagation. Cryopreservation is the storage of material at ultra-low temperature in liquid nitrogen (-1960C). It essentially involves suspensionof all metabolic processes and activities. iv) Conservation at Molecular Level (DNA level): Germplasm conservation at molecular level is now feasible and is attracting attention. Cloned DNA and material having DNA in its native state canall be used for genetic conservation. Non- viable material representing valuable genotypes stored in gene banks can all be used as sources of DNA libraries from where a relevant gene or a combination of genes can be recovered. v) Legal measures: Market demand for someanimal body parts like bones of tiger, rhinohorns, furs, ivory, skins, musk, peacock feathers, etc. results in killing of a large number of wild animals. The Wildlife Protection Act (1972) contain provisions for penalties or punishment for offender. Thus prevents poaching and illegal trade. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) CLIMATE CHANGE The periodic modification of Earth’s climate brought about due to the changes in the atmosphere as well as the interactions between the atmosphere and various other geological, chemical, biological and geographical factors within the Earth’s system is called Climate change. Factors Affecting Climate Change Natural Factors – affect the climate over a period of thousands to millions of years. Such as – Continental Drift – have formed millions of years ago when the landmass began to drift apart due to plate displacement. This impacts climate change due to the change in the landmass’s physical features and position and the change in water bodies’ position like the change in the follow of ocean currents and winds. Volcanism – Volcanic eruption emits gasses and dust particles that last for a longer period causing a partial block of the Sun rays thus leading to cooling of weathers and influencing weather patterns. Changes in Earth’s Orbit – A slight change in the Earth’s orbit has an impact on the sunlight’s seasonal distribution reaching earth’s surface across the world. There are three types of orbital variations – variations in Earth’s eccentricity, variations in the tilt angle of the Earth’s axis of rotation and precession of Earth’s axis. These together can cause Milankovitch cycles, which have a huge impact on climate and are well-known for their connection to the glacial and interglacial periods. Anthropogenic Factors – is mainly a human-caused increase in global surface temperature. Such as Greenhouse Gasses – these absorb heat radiation from the sun resulting in an increase in Global Temperature. GHGs mostly do not absorb solar radiation but absorb most of the infrared emitted by the Earth’s surface. Read more on Greenhouse Gasses on the given link. Global warming begins with the greenhouse effect, which is caused by the interaction between incoming radiation from the sun and the atmosphere of Earth. Atmospheric Aerosols – these can scatter and absorb solar and infrared radiation. Solar radiation scatters and cools the planet whereas aerosols on absorbing solar radiation increase the temperature of the air instead of allowing the sunlight to be absorbed by the Earth’s surface. Aerosols have a direct affect on climate change on absorption and reflection of solar radiation. Indirectly it can affect by modifying clouds formation and properties. It can even be transported thousands of kilometres away through winds and circulations in the atmosphere. Shift in land-use pattern – Most of the forests and land covers are replaced by agricultural cropping, land grazing, or for Industrial or commercial usage. The clearing of forest cover increases solar energy absorption and the amount of moisture evaporated into the atmosphere. The lower the albedo (reflectivity of an object in space), the more of the Sun’s radiation gets absorbed by the planet and the temperatures will rise. If the albedo is higher and the Earth is more reflective, more of the radiation is returned to space, leading to the cooling of the planet. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Effects of climate change in India  Extreme Heat: India is already experiencing a warming climate. Unusual and unprecedented spells of hot weather are expected to occur far more frequently and cover much larger areas. Under 4°C warming, the west coast and southern India are projected to shift to new, high- temperature climatic regimes with significant impacts on agriculture.  Changing Rainfall Patterns: A decline in monsoon rainfall since the 1950s has already been observed. A 2°C rise in the world’s average temperatures will make India’s summer monsoon highly unpredictable. At 4°C warming, an extremely wet monsoon that currently has a chance of occurring only once in 100 years is projected to occur every 10 years by the end of the century. Dry years are expected to be drier and wet years wetter.  Droughts: Evidence indicates that parts of South Asia have become drier since the 1970s with an increase in the number of droughts. Droughts have major consequences. In 1987 and 2002-2003, droughts affected more than half of India’s crop area and led to a huge fall in crop production. Droughts are expected to be more frequent in some areas, especially in north- western India, Jharkhand, Orissa, and Chhattisgarh. Crop yields are expected to fall significantly because of extreme heat by the 2040s.  Groundwater: Even without climate change, 15% of India’s groundwater resources are overexploited. Falling water tables can be expected to reduce further on account of increasing demand for water from a growing population, more affluent lifestyles, as well as from the services sector and industry.  Glacier Melt: Most Himalayan glaciers have been retreating over the past century. At 2.5°C warming, melting glaciers and the loss of snow cover over the Himalayas are expected to threaten the stability and reliability of northern India’s primarily glacier-fed rivers. Alterations in the flows of the Indus, Ganges, and Brahmaputra rivers could significantly impact irrigation, affecting the amount of food that can be produced in their basins as well as the livelihoods of millions of people  Sea level rise: With India close to the equator, the sub-continent would see much higher rises in sea levels than higher latitudes. Sea-level rise and storm surges would lead to saltwater intrusion in the coastal areas, impacting agriculture, degrading groundwater quality, contaminating drinking water, and possibly causing a rise in diarrhoea cases and cholera outbreaks, as the cholera bacterium survives longer in saline water. Kolkata and Mumbai, both densely populated cities, are particularly vulnerable to the impacts of sea-level rise, tropical cyclones, and riverine flooding.  Apart from this food and energy security are also major concerns. Water scarcity, health hazards among the masses, and migration and political conflicts are expected to grow. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) India’s response to Climate Change  National Action Plan on Climate Change (NAPCC): outlines existing and future policies and programs addressing climate mitigation and adaptation. The Action Plan identifies eight core “national missions” running through to 2017: Solar Energy; Enhanced Energy Efficiency; Sustainable Habitat; Water; Sustaining the Himalayan Ecosystem; Green India; Sustainable Agriculture; and Strategic Knowledge for Climate Change. Most of these missions have strong adaptation imperatives.  National Clean Energy Fund: The Government of India created the National Clean Energy Fund (NCEF) in 2010 for financing and promoting clean energy initiatives and funding research in the area of clean energy in the country. The corpus of the fund is built by levying a cess of INR 50 (subsequently increased to INR 100 in 2014) per tonne of coal produced domestically or imported.  Paris Agreement: Under the Paris Agreement, India has made three commitments. India’s greenhouse gas emission intensity of its GDP will be reduced by 33-35% below 2005 levels by 2030. Alongside, 40% of India’s power capacity would be based on non-fossil fuel sources. At the same time, India will create an additional ‘carbon sink’ of 2.5 to 3 billion tonnes of Co2 equivalent through additional forest and tree cover by 2030.  International Solar Alliance: ISA was launched at the United Nations Climate Change Conference in Paris on 30 November 2015 by India and France, in the presence of Mr. Ban Ki Moon, former Secretary-General of the United Nations.  Bharat Stage (BS) Emission Norms: Emissions from vehicles are one of the top contributors to air pollution, which led the government at the time to introduce the BS 2000 (Bharat Stage 1) vehicle emission norms from April 2000, followed by BS-II in 2005. BS-III was implemented nationwide in 2010. However, in 2016, the government decided to meet the global best practices and leapfrog to BS-VI norms by skipping BS V altogether. All these efforts need to be implemented well to mitigate the effects of climate change. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) GLOBAL WARMING Global warming is the phenomenon of a gradual increase in the temperature near the earth’s surface. This phenomenon has been observed over the past one or two centuries. This change has disturbed the climatic pattern of the earth. However, the concept of global warming is quite controversial but the scientists have provided relevant data in support of the fact that the temperature of the earth is rising constantly. There are several causes of global warming, which have a negative effect on humans, plants and animals. These causes may be natural or might be the outcome of human activities. In order to curb the issues, it is very important to understand the negative impacts of global warming. Causes of Global Warming Following are the major causes of global warming: Man-made Causes of Global Warming Deforestation Plants are the main source of oxygen. They take in carbon dioxide and release oxygen thereby maintaining environmental balance. Forests are being depleted for many domestic and commercial purposes. This has led to an environmental imbalance, thereby giving rise to global warming. Use of Vehicles The use of vehicles, even for a very short distance results in various gaseous emissions. Vehicles burn fossil fuels which emit a large amount of carbon dioxide and other toxins into the atmosphere resulting in a temperature increase. Chlorofluorocarbon With the excessive use of air conditioners and refrigerators, humans have been adding CFCs into the environment which affects the atmospheric ozone layer. The ozone layer protects the earth surface from the harmful ultraviolet rays emitted by the sun. The CFCs have led to ozone layer depletion making way for the ultraviolet rays, thereby increasing the temperature of the earth. Industrial Development With the advent of industrialization, the temperature of the earth has been increasing rapidly. The harmful emissions from the factories add to the increasing temperature of the earth. In 2013, the Intergovernmental Panel for Climate Change reported that the increase in the global temperature between 1880 and 2012 has been 0.9 degrees Celsius. The increase is 1.1 degrees Celsius when compared to the pre-industrial mean temperature. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Agriculture Various farming activities produce carbon dioxide and methane gas. These add to the greenhouse gases in the atmosphere and increase the temperature of the earth. Overpopulation An increase in population means more people breathing. This leads to an increase in the level of carbon dioxide, the primary gas causing global warming, in the atmosphere. Natural Causes of Global Warming Volcanoes Volcanoes are one of the largest natural contributors to global warming. The ash and smoke emitted during volcanic eruptions goes out into the atmosphere and affects the climate. Water Vapour Water vapour is a kind of greenhouse gas. Due to the increase in the earth’s temperature, more water gets evaporated from the water bodies and stays in the atmosphere adding to global warming. Melting Permafrost Permafrost is frozen soil that has environmental gases trapped in it for several years and is present below Earth’s surface. It is present in glaciers. As the permafrost melts, it releases the gases back into the atmosphere, increasing Earth’s temperature. Forest Blazes Forest blazes or forest fires emit a large amount of carbon-containing smoke. These gases are released into the atmosphere and increase the earth’s temperature resulting in global warming. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Effects of Global Warming Following are the major effects of global warming: Rise in Temperature Global warming has led to an incredible increase in earth’s temperature. Since 1880, the earth’s temperature has increased by ~1 degrees. This has resulted in an increase in the melting of glaciers, which have led to an increase in the sea level. This could have devastating effects on coastal regions. Threats to the Ecosystem Global warming has affected the coral reefs that can lead to the loss of plant and animal lives. Increase in global temperatures has made the fragility of coral reefs even worse. Climate Change Global warming has led to a change in climatic conditions. There are droughts at some places and floods at some. This climatic imbalance is the result of global warming. Spread of Diseases Global warming leads to a change in the patterns of heat and humidity. This has led to the movement of mosquitoes that carry and spread diseases. High Mortality Rates Due to an increase in floods, tsunamis and other natural calamities, the average death toll usually increases. Also, such events can bring about the spread of diseases that can hamper human life. Loss of Natural Habitat A global shift in the climate leads to the loss of habitats of several plants and animals. In this case, the animals need to migrate from their natural habitat and many of them even become extinct. This is yet another major impact of global warming on biodiversity. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Global warming prevention: 1. Renewable energies The first way to prevent climate change is to move away from fossil fuels. What are the alternatives? Renewable energies like solar, wind, biomass and geothermal. 2. Energy & water efficiency Producing clean energy is essential, but reducing our consumption of energy and water by using more efficient devices (e.g. LED light bulbs, innovative shower systems) is less costly and equally important. 3. Sustainable transportation Promoting public transportation, carpooling, but also electric and hydrogen mobility, can definitely help reduce CO2 emissions and thus fight global warming. 4. Sustainable infrastructure In order to reduce the CO2 emissions from buildings - caused by heating, air conditioning, hot water or lighting - it is necessary both to build new low energy buildings, and to renovate the existing constructions. 5. Sustainable agriculture & forest management Encouraging better use of natural resources, stopping massive deforestation as well as making agriculture greener and more efficient should also be a priority. 6. Responsible consumption & recycling Adopting responsible consumption habits is crucial, be it regarding food (particularly meat), clothing, cosmetics or cleaning products. Last but not least, recycling is an absolute necessity for dealing with waste. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) OZONE LAYER DEPLETION “Ozone layer depletion is the gradual thinning of the earth’s ozone layer in the upper atmosphere caused due to the release of chemical compounds containing gaseous bromine or chlorine from industries or other human activities.” Ozone layer depletion is the thinning of the ozone layer present in the upper atmosphere. This happens when the chlorine and bromine atoms in the atmosphere come in contact with ozone and destroy the ozone molecules. One chlorine can destroy 100,000 molecules of ozone. It is destroyed more quickly than it is created. Some compounds release chlorine and bromine on exposure to high ultraviolet light, which then contributes to ozone layer depletion. Such compounds are known as Ozone Depleting Substances (ODS). The ozone-depleting substances that contain chlorine include chlorofluorocarbon, carbon tetrachloride, hydrochlorofluorocarbons, and methyl chloroform. Whereas, the ozone-depleting substances that contain bromine are halons, methyl bromide, and hydro bromofluorocarbons. Causes of Ozone Layer Depletion Ozone layer depletion is a major concern and is associated with a number of factors. The main causes responsible for the depletion of the ozone layer are listed below: Chlorofluorocarbons Chlorofluorocarbons or CFCs are the main cause of ozone layer depletion. These are released by solvents, spray aerosols, refrigerators, air-conditioners, etc. The molecules of chlorofluorocarbons in the stratosphere are broken down by ultraviolet radiations and release chlorine atoms. These atoms react with ozone and destroy it. Unregulated Rocket Launches Researches say that the unregulated launching of rockets results in much more depletion of the ozone layer than the CFCs do. If not controlled, this might result in a huge loss of the ozone layer by the year 2050. Nitrogenous Compounds The nitrogenous compounds such as NO2, NO, N2O are highly responsible for the depletion of the ozone layer. Natural Causes The ozone layer has been found to be depleted by certain natural processes such as Sun-spots and stratospheric winds. But it does not cause more than 1-2% of the ozone layer depletion. The volcanic eruptions are also responsible for the depletion of the ozone layer. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Ozone Depleting Substances (ODS) “Ozone-depleting substances are the substances such as chlorofluorocarbons, halons, carbon tetrachloride, hydrofluorocarbons, etc. that are responsible for the depletion of the ozone layer.” Following is the list of some main ozone-depleting substances and the sources from where they are released: Ozone-Depleting Substances Sources Chlorofluorocarbons (CFCs) Refrigerators, air-conditioners, solvents, dry-cleaning agents, etc. Halons Fire-extinguishers Carbon tetrachloride Fire extinguishers, solvents Methyl chloroform Adhesives, aerosols Hydrofluorocarbons fire extinguishers, air-conditioners, solvents Effects Of Ozone Layer Depletion The depletion of the ozone layer has harmful effects on the environment. Let us see the major effects of ozone layer depletion on man and environment. 1. Effects on Human Health Humans will be directly exposed to the harmful ultraviolet radiation of the sun due to the depletion of the ozone layer. This might result in serious health issues among humans, such as skin diseases, cancer, sunburns, cataract, quick ageing and weak immune system. 2. Effects on Animals Direct exposure to ultraviolet radiations leads to skin and eye cancer in animals. 3. Effects on the Environment Strong ultraviolet rays may lead to minimal growth, flowering and photosynthesis in plants. The forests also have to bear the harmful effects of the ultraviolet rays. 4. Effects on Marine Life Planktons are greatly affected by the exposure to harmful ultraviolet rays. These are higher in the aquatic food chain. If the planktons are destroyed, the organisms present in the food chain are also affected. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) Solutions to Ozone Layer Depletion The depletion of the ozone layer is a serious issue and various programmes have been launched by the government of various countries to prevent it. However, steps should be taken at the individual level as well to prevent the depletion of the ozone layer. Following are some points that would help in preventing this problem at a global level: Avoid Using ODS Reduce the use of ozone depleting substances. E.g. avoid the use of CFCs in refrigerators and air conditioners, replacing the halon based fire extinguishers, etc. Minimise the Use of Vehicles The vehicles emit a large amount of greenhouse gases that lead to global warming as well as ozone depletion. Therefore, the use of vehicles should be minimised as much as possible. Use Eco-friendly Cleaning Products Most of the cleaning products have chlorine and bromine releasing chemicals that find a way into the atmosphere and affect the ozone layer. These should be substituted with natural products to protect the environment. Use of Nitrous Oxide should be Prohibited The government should take actions and prohibit the use of harmful nitrous oxide that is adversely affecting the ozone layer. People should be made aware of the harmful effects of nitrous oxide and the products emitting the gas so that its use is minimised at the individual level as well. Prof. HIMANSHU G. F.Y.B.Sc (Environmental Studies) ACID RAIN Acid rain is made up of highly acidic water droplets due to air emissions, most specifically the disproportionate levels of sulphur and nitrogen emitted by vehicles and manufacturing processes. It is often called acid rain as this concept contains many types of acidic precipitation. Causes of Acid Rain The causes of acid rain are Sulphur and Nitrogen particles which get mixed with the wet components of rain. Sulphur and Nitrogen particles which get mixed with water are found in two ways either man- made i.e as the emissions that are given out from industries or by natural causes like lightning strike in the atmosphere releasing nitrogen oxides and volcanic eruptions releasing sulphur oxide. According to the Royal Society of Chemistry, which considers him the “father of acid rain,” the word acid rain was invented in 1852 by Scottish chemist Robert Angus Smith. Smith decided on the word while studying rainwater chemistry near industrial towns in England and Scotland. The regular clean rain we experience, even though it is not clean i.e water and carbon dioxide react together to form weak carbonic acid which essentially by itself is not extremely harmful. The reaction occurring is : H2O (l) + CO2 (g) ⇌ H2CO3 (aq) The pH value of regular rainwater is around 5.7, giving it an acidic nature. The oxides of nitrogen and sulphur are blown away by the wind along with the dust particles. They settle on the earth’s surface after coming down in the form of precipitation. Acid rain is essentially a by-product of human activities which emit oxides of nitrogen and sulphur in the atmosphere. Example – the burning of fossil fuels, unethical waste emission disposal techniques. ulphur dioxide and nitrogen dioxide undergo oxidation, and then they react with water resulting in the formation of sulphuric acid and nitric acid, respectively. The following reaction will clarify the acid formation reaction: 2SO2 (g) + O2 (g) + 2H2O (l) →