Introduction to Environmental Science PDF

Dr. K. SAMBANDAN Dept of Botany AAGA&SC, KKL Unit 1: Introduction to environmental studies Multidisciplinary nature of environmental studies Scope and importance; Concept of sustainability and sustainable development.  ENVIRONMENTAL STUDIES The word environment is derived fr...

Dr. K. SAMBANDAN Dept of Botany AAGA&SC, KKL Unit 1: Introduction to environmental studies Multidisciplinary nature of environmental studies Scope and importance; Concept of sustainability and sustainable development.  ENVIRONMENTAL STUDIES The word environment is derived from the French word “Environ” meaning SSurroundings. Every organisms is surrounded by materials and forces which constitute its environment. Environment creates favourable conditions for the existence and development of living organisms. Environment – The sum of total of all the living and non-living things around us influencing one another.  Environmental science the scientific study of human interactions with the environment. It is the branch of science concerned with the relations between organisms and their environment. Literally, environment means the surrounding external conditions influencing development or growth of people, animal or plants; living or working conditions etc. Types of Environment  Types of Environment Natural environment Natural environment is characterized by natural components. All biotic (living) and abiotic (non-living) are created through a natural process. Natural components do not require any human support.  Man-made environment It is powerful environment modified using modern technologies according to the needs created by humans. Components of the Environment Abiotic or Non-living components Biotic or Living components Energy components  Biotic or Living components Example: Animals, plants and micro organisms. Biosphere: The living organism live and interact with physical environment (soil, water and air) is called biosphere. Functions: Plants ↔ animals Abiotic or Non-living or Physical components Example : Air, water, soil and minerals. Abiotic components enter the body of living organisms directly or indirectly take part in metabolic activities and then return to the environment.  Abiotic – three categories 1. Atmosphere 2. Lithosphere 3. Hydrosphere 1. Atmosphere Air envelopes the earth is known as atmosphere. It extends up to 500 kms from the earth surface. It comprises 78% of Nitrogen, 21% of oxygen and 1% of other gases.  Structure of atmosphere Sl Region Altitude in Temperature Chemical no. km in C species 1 Troposhere 0-18 15 to -56 N2,H2O,CO2, O2 2 Stratosphere 18-50 -56 to -2 Ozone 3 Mesosphere 50-85 -2 to -92 NO+, O2+ 4 Thermosphere 85-500 -92 to NO+, O+, 1200 O2+ 5 Exosphere Upto 1600 Very high He, H2  Composition of Atmospheric Air Gas Relative %by Volume Nitrogen (N2)- 78.09 Oxygen (O2)- 20.93 Argon (A)- 00.93 Carbon-di-oxide- (CO2)- 0.032 Miscellaneous- 0.02 Total 100.000  Functions of atmosphere It maintains the heat balance on the earth by absorbing the IR radiations The gaseous constituents play an important role in sustaining life on earth Oxygen - supports life of living organisms CO2- essential for photosynthetic activity of plants Nitrogen – essential nutrient for plant growth  Lithosphere The soil and rock components of the earth Functions : 1. Home for human beings and wildlife 2. Storehouse of minerals and organic matter  Hydrosphere The aqueous envelope of the earth. Oceans, lakes,streams,rivers and water vapour constitute hydrosphere. 97% of earth water is in oceans. 3% is available as fresh water. Functions : 1. It is used for drinking purpose and also supports the aquatic life. 2. It is also used for irrigation, power production, industries and transport.  Energy components The components of energy flows across biotic and abiotic components. Example : Solar energy, Nuclear energy, Geochemical energy, Thermo electrical energy, etc.  Sustainable development Sustainable development is defined as Development that meets the needs of the present without compromising the ability of future generations. It also looks at the equity between countries, races and gender and ages. It includes social and economic development on one hand and the requirements of environment on the other. It is a process which leads to a better quality of life while reducing the impact on the environment.  Sustainable development Causes 1. Raising population 2. Increasing poverty 3. Pollution loads Measures to be taken Any economic activity without healthy 1. Use of appropriate Technology balance between 2. Minimize the use of resources environment leads to 3. Creating awareness Unsustainability 4. Discourage earth degrading behavior 5. Govt Programmes to reduce population, poverty and pollution Food for a Week, Darfur Refugees, Chad, Africa Source: Menzel, 2005 Food for a Week, for German Family © 2005 PETER MENZEL PHOTOGRAPHY Source: Menzel, 2005