ECOLOGY, ENVIRONMENT AND DISASTER MANAGEMENT

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Table of Contents 1. BIOSPHERE AND WORKING OF ECOSYSTEMS .................................................................................................... 2 1.1. Biosphere ....................... ... ............................................................................................................................ 2 1.2. Ecology ...................................................................................................................................................... 2 1.3. Ecosystem .................................................................................................................................................. 2 1.3.1. Components of Ecosystem .................................................................................................................. 2 1.3.2. Types of Ecosystem ............................................................................................................................. 3 1.3.3. Energy Flow in Ecosystem .................................................................................................................... 3 1.3.4. Productivity ......................................................................................................................................... 6 1.3.5. Ecological Niche................................................................................................................................... 6 1.3.6. Habitat ................................................................................................................................................ 6 1.3.7. Species structure ................................................................................................................................. 7 1.3.8. Decomposition .................................................................................................................................... 7 1.3.9. Biomagnification ................................................................................................................................. 7 1.4. Nutrient Cycles........................................................................................................................................... 8 1.5. Succession................................................................................................................................................ 11 1.5.1. Sere ................................................................................................................................................... 11 1.5.2. Climax ............................................................................................................................................... 11 1.6. Biotic Potential ......................................................................................................................................... 12 1.7. Carrying Capacity ..................................................................................................................................... 12 1.8. Ecosystem Services .................................................................................................................................. 12 1.9. Ecotone.................................................................................................................................................... 13 1.9.1. Edge Effect ........................................................................................................................................ 13 1.9.2. Home Range ...................................................................................................................................... 13 1.9.3. Other Important terms: ..................................................................................................................... 13 1.10. UPSC QUESTIONS RELATED TO ABOVE TOPICS ....................................................................................... 14 1.11. PRELIMS QUESTIONS .............................................................................................................................. 14 2 www.visionias.in ©Vision IAS 1. BIOSPHERE AND WORKING OF ECOSYSTEMS 1.1. BIOSPHERE Biosphere is that part of lithosphere, hydrosphere and atmosphere where plants and human beings live. Biosphere contains all life forms on earth. The biosphere consists of all the living organisms (the biotic component), energy and physical environment (the abiotic component) and there are continuous interactions between living organisms and physical environment and among the living organisms themselves.  The biosphere consists of two major systems viz. (i) terrestrial biomes systems and (ii) aquatic biomes systems.  The terrestrial biomes systems are further comprised of three subsystems viz., (i) plant system, (ii) animal system and (iii) soil system. These subsystems are intimately interrelated among themselves through the cyclic pathways of movements and transfer of energy and materials.  The aquatic biomes systems are also composed of three sub-systems viz. : (i) Plant system, (ii) Animal system, and (iii) Nutrients. These three sub-systems of aquatic biomes system of the biosphere are also intimately interrelated through cyclic pathways of movements of energy and matter among themselves.  Man depends on biosphere to fulfill many of his needs like food, drugs, clothes, housing, paper and tourism and environment. 1.2. ECOLOGY Ecology can be defined as a scientific study of the interactions of organisms with their physical environment and with each other. The term ecology is derived from the Greek word ‘oikos’ meaning ‘house’, combined with the word ‘logy’ meaning the ‘science of’ or ‘the study of ’. Literally, ecology is the study of the earth as a ‘household’, of plants, human beings, animals and micro-organisms. They all live together as interdependent components. A German zoologist Ernst Haeckel, who used the term as ‘oekologie’ in 1869, became the first person to use the term ‘ecology’. The study of interactions between life forms (biotic) and the physical environment (abiotic) is the science of ecology. 1.3. ECOSYSTEM An ecosystem is a functional unit of nature, where living organisms interact among themselves and also with the surrounding physical environment. 1.3.1. COMPONENTS OF ECOSYSTEM There are four basic components of an ecosystem. 1. The abiotic part, which is the non-living environment. 2. The producers or autotrophs, the green plants capable of producing their own food by using the energy of sunlight to make carbohydrates from water and carbon dioxide; this process is called photosynthesis. [Show More]

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