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Tuesday, March 23, 2010

Basic questions about environment

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What is the science of Environment?
Environment may be defined as ‘Complete range of various sets of external conditions comprising- physical, biological, and for human beings- cultural, economic and political conditions in which human beings and other life forms exist in continuous interactions among themselves.

The term Environment has variously been defined by different scholars from time to time. According to S.C.Kendeigh (1974), ‘the sum total of physical (abiotic) and biotic conditions influencing the responses of the organism, is called as its Environment’.

 Environment and Environmental Science
            Environment in real life situations ranges from indoor to outdoor life of a man. In indoor life, the environment embraces everything pertaining to living conditions ranging from the quality of the building materials; design and construction of the house; manners of keeping grains, fruits and vegetables etc.; types and qualities of water being consumed; eating habits, health and hygiene; uses of cosmetics and luxuries; washing materials and equipments; means of recreation and their uses; types of dresses and dress – designs, clothing materials; conditions of surrounding and drainage systems; waste disposal systems; types of vegetation growing naturally or grown around; types of locations of cattle sheds etc.

In outdoor life the environment embraces places of activities/ services; industries- types and locations; types of farms and agricultural practices; urbanisation; town planning; building plans; provisions of roof top water harvesting; roads and railway tracks and types of human habitations near them (conditions of slums); positions and conditions of water bodies; dumping sites; conditions of vehicles moving along roads; management of transport and traffic control systems etc.

Going through above accounts, we observe that the environment is a vast area comprising various interlinked components. Hence, the study of environment comprises various interlinked disciplines of knowledge mainly pertaining to basic and applied sciences together with engineering, public administration, socioeconomics, ethics and law. Total of the human resources alongwith the government machinery and social organisations are needed to be applied in the task of management of various environmental fractions. For this, involvement of high degree of awareness, knowledge, attitudes, skills together with the public participation, social, financial, political, moral and administrative support is required on the priority basis. All these areas are covered in the study of environmental science. Environmental science is the field of study which deals in all the related perspectives in integrated, interdisciplinary and holistic manner.

As environment is common heritage and property of all nations of the world, the science of environment should also combine relevant matter so as to promote the value and necessities of local, national and international co-operation in the prevention and solution of environmental problems across the globe. 

What is Hydrological cycle? What are its types and how does it go on?
Just as the differential heating of land surface causes circulation of air in the atmosphere, the differential heating of water surface causes circulation of water in the environment. The circulation of water through different spheres of the natural environment is called as Hydrological Cycle or the Water cycle.

Types of Hydrological Cycles

The Hydrological Cycle in nature can be observed in two overlapping forms (i) the Global Hydrological Cycle and (ii) the Biological Hydrological Cycle. As the name indicates, the global hydrological cycle operates on global level and it does not involve living systems. On the other hand, the biological hydrological cycles operate at local levels and these essentially involve living systems of the local areas. This is the reason why these hydrological cycles determine the micro climates that exist at local levels. However biological hydrological cycles remain linked to the global hydrological cycles as they take water from the global hydrological cycles only. Let us see how a hydrological cycle operates in nature.

 Operation of a simple Hydrological Cycle

The operation of a simple hydrological cycle is being summarised below-

            (i)When the temperature of air is high, the water contained in bodies of plants and animals gets evaporated and comes out as water vapour which goes up and contributes to the formation of clouds. The process, through which water contained inside plant-bodies escapes away into the atmosphere in the form of water vapour from their surfaces, is called as Transpiration. From animal bodies, water comes out as sweat and gets evaporated to join the atmosphere.
            (ii)The water retained inside soil also goes up in the air to contribute to the formation of clouds due to the heating effects of sun rays.
            (iii)The rain water which runs down  to rivers and oceans gets evaporated and the water vapour goes up to contribute in the cloud formation.
            (IV)The ground water which is extracted out through different mechanical devices like pump sets, tube wells and wells etc. also join atmosphere to contribute to the formation of clouds. Clouds when encounter the cold air, get condensed to water drops. This is how the rain occurs and the Hydrological Cycle goes on and on.

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