UGC NET/JRF Environmental Science - PDF

Unit-I: Fundamentals of Environmental Sciences The word environment is derived from the French verb “environner”, which means to “encircle” or “surround.” Thus, our environment can be defined as the physical, chemical and biological world that surrounds us, as well as the complex of social and c...

Unit-I: Fundamentals of Environmental Sciences The word environment is derived from the French verb “environner”, which means to “encircle” or “surround.” Thus, our environment can be defined as the physical, chemical and biological world that surrounds us, as well as the complex of social and cultural conditions affecting an individual or community. This broad definition includes the natural world and the technological environment, as well as the cultural and social contexts that shape human lives. The biologist Jacob Van Uerkal (1864-1944) introduced the term ‘environment’ in Ecology. The term Environment can be broadly defined as one’s surroundings. To be more specific we can say that it is the physical and biological habitat that surrounds us, which can be felt by our physical faculties (seen, heard, touched, smelled and tasted). Some important definitions of environment are as under:  According to Boring, ‘A person’s environment consists of the sum total of the stimulation which he receives from his conception until his death.’ Indicating that environment comprises various types of forces such as physical, intellectual, mental, economical, political, cultural, social, moral and emotional.  Douglas and Holland defined that ‘The term environment is used to describe, in aggregate, all the external forces, influences and conditions, which affect the life, nature, behaviour and the growth, development and maturity of living organisms’. Environmental science is essentially the application of scientific methods and principles to the study of environmental issues, so it has probably been around in some form as long as science itself. Environmental science is often confused with other fields of related interest, especially ecology, environmental studies, environmental education, and environmental engineering. Environmental science is not constrained within any one discipline and it is a comprehensive field. A considerable amount of environmental research is accomplished in specific department such as chemistry, physics, civil engineering, or the various biology disciplines. Importance of Environment studies The environment studies make us aware about the importance of protection and conservation of our mother earth and about the destruction due to the release of pollution into the environment. The increase in human and animal population, industries and other issues make the survival cumbersome. A great number of environment issues have grown in size and make the system more complex day by day, threatening the survival of mankind on earth. Environment studies have become significant for the following reasons: 1. Environment issues are being of global 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 require international efforts and cooperation to solve them. 2. Development and environment Development leads to Urbanization, Industrial Growth, Telecommunication and Transportation Systems, Hi-tech Agriculture and Housing etc. However, it has become phased out in the developed world. The North intentionally moves their dirty factories to South to cleanse their own environment. When the West developed, it did so perhaps in Page | 10 ignorance of the environmental impact of its activities. Development of the rich countries of the world has undesirable effects on the environment of the entire world. 3. Explosive increase in pollution World census reflects that one in every seven persons in this planet 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 soil 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, especially for developing countries to find alternative paths to an alternative goal. We need a goal as under 1. A true goal of development with an environmentally sound and sustainable development. 2. A goal common to all citizens of our planet earth. 3. A goal distant from the developing world in the manner it is from the over-consuming wasteful societies of the “developed” world. 4. It is utmost important for us to save the humanity from extinction because of our activities constricting the environment and depleting the biosphere, in the name of development. 5. Need for Wise Planning of Development Our survival and sustenance depend on resources availability. Hence Resources withdraw, processing and use of the products have all to be synchronised with the ecological cycle. In any plan of development our actions should be planned ecologically for the sustenance of the environment and development. The two major classifications of environment are: (A) Physical Environment: External physical factors like Air, Water, and Land etc. This is also called abiotic Environment. (B) Living Environment: All living organisms around us viz., plants, animals, and microorganisms. This is also called biotic Environment. Earth’s environment can be further subdivided into the following four segments: (1) Lithosphere (2) Hydrosphere (3) Atmosphere (4) Biosphere Lithosphere The earth’s crust consisting of the soil and rocks is the lithosphere. The soil is made up of inorganic and organic matter and water. The main mineral constituents are compounds or mixtures derived from the elements of Si, Ca, K, Al, Fe, Mn, Ti, O, etc. (Oxides, Silicates, Page | 11 and Carbonates). The organic constituents are mainly polysaccharides, organo compounds of N, P and S. The organic constituents even though form only around 4% – 6% of the lithosphere, they are responsible for the fertility of the soil and hence its productivity. Hydrosphere This comprises all water resources both surface and ground water. The world’s water is found in oceans and seas, lakes and reservoirs, rivers and streams, glaciers and snowcaps in the Polar Regions in addition to ground water below the land areas. The distribution of water among these resources is  Oceans and seas – 96-97%  Glaciers and polar icecaps – 2-3%  Fresh water -