First Edition, 2009 ISBN 978 93 80168 58 6 © All rights reserved. Published by: Global Media 1819, Bhagirath Palace, Chandni Chowk, Delhi-110 006 Email:
[email protected] Table of Contents 1. Basic System 2. Evolution and Development 3. Fundamental Issues 4. Problem of Pollution 5. Population on Rise 6. The Animals 7. Planet of Earth 8. The Forestry 9. The Settlements 10. Educational Aspects 11. Value of Learning 12. Learning Programme 13. Evaluation Process 14. Technological Aspects 15. National Concerns 16. International Concerns 1 Basic System The term ecosystem was introduced by A.G. Tansley in 1935. Before him, Mobins had used the term biocoenosis while Forbes coined the term Microcosm for the community of the organisms. Sukachev employed the term biogeocoenosis as synonym of ecosystem. “Ecosystem is a segment of nature consisting of community of living beings and the physical environment, both interacting and exchanging material between them.” According to Evans “the ecosystem involves the circulation, transformation and accumulation of energy and matter through the medium of living organisms and their activities. According to Fitzpatrick a group of organisms interacting among themselves and with environment is known as ecosystem. An ecosystem may be small like a drop of pond water (micro ecosystem) or may be as large as ocean. Each ecosystem has a distinct community with a distinct environment. Therefore, different ecosystems are identified by their bionics e.g., freshwater ecosystem, marine ecosystem, desert ecosystem, grassland ecosystem, tropical ecosystem. However, these ecosystems are not isolated. All the ecosystems of the world are inter-related and exchange materials amongst themselves. Therefore, some workers Environmental Science 2 consider the whole earth as ecosystem and call it biosphere or ecosphere. The Significance 1. Ecosystem study gives information about the amount of available solar energy in an area. 2. It gives data about the availability of mineral elements, their utilisation and recycling. 3. Inter relationships between various types of organisms as well as between organisms and abiotic environment can be known. 4. Productivity of producers and consumers is known. 5. The maximum number of producers and consumers of various categories which can be supported in the ecosystem is known. Main Features (i) The ecosystem is a unit of organisms connected to one another and to their environment within given space and time limit. (ii) Any system composed of physical, chemical and biological processes within a space and time unit. (iii) It is composed of three basic components-biotic (biome), abiotic (habitat) and energy components. (iv) It occupies certain well defined area on the earth-space and time unit. (v) Ecosystem of any given space-time-unit represents the sum of all living organisms and physical environment. (vi) It is an open system which is characterised by continuous input and output of matter and energy. (vii) There are complex sets of interactions between biotic and abiotic components including energy components on the one hand and among the organism on the other hand. (viii) It is powered by energy of various sorts but the solar energy is the most significant and tends to be relatively stable equilibrium. It has the natural resource system. Basic System 3 (ix) It is well organised and structured system. The study of ecosystem development is helpful in the environmental planning from ecological point of view. Different Varieties Ecosystem can be natural or artificial, large or small, permanent or temporary, complete or incomplete. Natural Ecosystem : It is an ecos