Welcome dear students! Today we are going to learn about Biosphere from Class 8 Social_Science. After studying this chapter, you will learn the meaning of biosphere and its importance. You will also learn about the meaning of environment, environmental pollution, types of pollution, and preventive measures.
Do you know what the Earth has given to us? But what are we giving back to the earth? Earth is the only planet which has various forms of life on it. Biosphere is the part of the earth where life exists. The biosphere is the fourth component of the earth and it is the totality of all living things on earth.
Ecology is the study of the interaction of living organisms with their physical, chemical and biological environment. In a natural environment, there is a perfect balance between the various organisms living together in the biosphere. This is known as ecological balance.
Ecosystem is a community of plants and animals, together with their immediate environment, including the inanimate part of that environment. It is also defined as the total assemblage of components entering into the interactions of a group of organisms. Without ecosystem or ecological balance in the biosphere, one cannot imagine the existence of plants, animals and micro organisms either single or in community. Every organism adjusts itself with its physical habitat.
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Environment is the surrounding where an organism, a community or an object exists. It creates favourable conditions for the existence and development of all living organisms. The environment is of two types: Natural or geographical, and Cultural or man-made.
Environmental pollution is the unfavourable alteration of our surrounding, wholly or partly by human action through direct and indirect effects. Environmental pollution is one of the most terrifying ecological crisis of today. The factors like over population, industrialization, urbanization, over exploitation of resources, and over utilization of automobiles have influenced a change in the living conditions of plants, animals and human beings.
Pollutants are the substances that cause pollution. Pollutants are natural and man-made. The man-made pollutants are considered to be more dangerous and hazardous than natural pollutants. The pollutants may be visible like smoke, poisonous gases, dust, garbage, and sewage. They may also be invisible like bacteria, and toxic chemicals mixed with water, food, and soil.
Types of Environmental Pollution: Environmental pollution is of different types. On the basis of pollutants and medium of pollution they can be classified into the following types: Air pollution, Water pollution, Soil pollution and Noise pollution.
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Let us look at Air pollution first. According to World Health Organisation, air pollution is defined as substances put into the air by the activity of mankind in concentration, sufficient to cause harmful effects to his health, vegetation and property. The important sources of air pollutants are Natural sources which include volcanoes, forest fire, and cosmic dust. Man-made sources include gases from industries, domestic use, automobiles, mining, nuclear power plants, and nuclear explosions. The important pollutants are carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides, chlorofluorocarbons, and hydrocarbons. The important effects are change in weather and climatic conditions, ozone depletion, greenhouse effect, global warming, effect on human health, problem with respiratory system, and effect on life of animals and plants. Measures to control air pollution are control of gaseous pollutants, control of emission from automobiles, planting of more trees, use of non-conventional energy sources, awareness programme, legal control, literacy and education.
Next, let us learn about Water pollution. Water pollution is alteration in physical, chemical and biological characteristics of water which may have harmful effects on human and aquatic life. The important sources of water pollution are Natural sources like soil erosion, landslides, volcanic eruption, and decay and decomposition of plants and animals. Man-made sources include industrial effluents, urban waste, domestic waste, agricultural waste, thermal waste, oil spill, offshore drilling, and nuclear waste. Water pollution is of different types: Sea or Ocean water pollution, Ground water pollution, River water pollution, and Lake pollution.
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The important effects of water pollution are it spreads water-borne diseases and epidemics like cholera, typhoid, diarrhea, jaundice, TB, causes death of aquatic life, affects irrigation water and on agricultural crops, nature and features of water. Measures to control water pollution are industrial effluents must be treated, drinking water sources must be kept clean, sewage treatment plants, and disposal of waste on the water bodies must be controlled.
Now we will study Soil pollution. Soil pollution is decrease in the quality of soils either due to human sources or natural sources or by both. It results in the increase of soil erosion, lack of humus, decrease in soil micro-organisms, and plant nutrients. Sources of soil pollution are industrial and mining waste, domestic and urban waste, agricultural waste, and nuclear waste. Effects of soil pollution are it decreases the fertility of the soil, converts the region into wasteland, and destroys the micro organisms in the soil. Measures to control soil pollution are controlled and judicious use of chemical fertilizers, pesticides and insecticides, proper disposal of industrial and urban waste, proper use of land and crop management, and awareness programme on proper soil utilization and its maintenance.
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Moving on to Noise pollution. Noise pollution is any undesirable sound dumped into the atmosphere leading to health hazards. The important sources of noise pollution are Natural sources like thunder, cyclones, heavy rainfall, hailstorms, waterfalls, and ocean waves. Man-made sources include industrial noise, automobiles, air crafts, domestic noise, and mining. Effects of noise pollution are noise pollution causes temporary or permanent hearing problem, headaches, restlessness, cardiovascular diseases, psychological disorder, behavioural changes, and lack of concentration. Measures to control noise pollution are industries must be located away from the residential areas, construction of sound proof walls in the factories, restricting unnecessary use of sirens, horns and loud speakers, airports must be located away from the residential zones, protective instruments for the workers in the industries, and noise producing vehicles must be checked.
Let us now understand Global warming. The temperature of the earth is increasing slowly over the years. For the last few years global temperature has increased. This phenomenon is termed as Global warming. The warming of atmosphere is caused by greenhouse effect and trapping of heat by the atmosphere. The world getting warmer, climatic zones are shifting, glaciers are melting and sea level is rising due to global warming, for example, high rate of melting of ice in Himalayas, Arctic and Antarctic regions.
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Next is the Greenhouse effect. The energy that the earth receives from the sun has to be balanced by the radiation emitted from the earth surface. The use of fossil fuels is increasing greenhouse gases in the atmosphere. Carbon dioxide and other greenhouse gases trap the heat radiated from the earth. Thus increasing of greenhouse gases is causing an increase of temperature. This is called Greenhouse effect.
Ozone depletion is another critical topic. Ozone is a thin layer of gas found in stratosphere. Ozone absorbs ultraviolet rays and protects all forms of life on the earth surface. In recent years the use of air conditioners, refrigerators, sprays and deodorants are destroying the ozone due to the synthetic chemicals released into the atmosphere, primarily chlorofluorocarbons. The highest ozone depletion in the world is recorded in the atmosphere over Antarctica. The ozone depletion has caused the ozone hole. This has to be controlled for the sake of the people of the present and future generation.
Acid rain contains high amounts of acids particularly sulphuric acid and carbon monoxide. It is caused when the rain drops pass through the polluted atmosphere. The rainfall with poisonous acids kill marine organisms. Acid rain is damaging forests, agricultural crops, old buildings, and monuments. Acid rain is also referred as lake killer. The Black Triangle stretching over Poland, Czeck Republic and South-east Germany is one of the worst acid rain affected regions in the world.
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Bio-Diversity is the variety of flora and fauna in a region. Distribution of different kinds of plant and animal species in a region shows the richness of biodiversity. The maintenance of biodiversity is very important both for the quality of environment and also for human survival. The conservation of biodiversity is very important to save and protect rare plants and animal species. Providing good environmental condition for their living is the best means of protection.
The earth is the only living planet in our solar system. The way in which changes, disturbances, hazards are taking place on the earth, can lead to the destruction of the quality of life on our earth in the near future. To save Earth and Mother Planet we must educate people, formulate awareness programmes, utilize resources judiciously, control pollution awareness through education, symposiums, seminars, skits, films, and summits. These are necessary to save our Mother Earth. Save Earth, Save Mother Planet.
The textbook includes an Exercises section titled Exercises I. As the specific questions are not provided in our source text, please refer to your physical textbook for the exact questions. However, to ensure you are fully prepared for your exams, I recommend you practice answering questions on the definitions of biosphere, ecosystem, and the four types of pollution, along with their sources, effects, and control measures, exactly as we have covered them today.
Thank you for listening! Keep revising and practicing. Goodbye! [CHAPTER_COMPLETE]