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  • 1. Ecosytem The term Ecosystem was first proposed by ecologist A. G. Tansely who defined ecosystem as the system resulting from the integration of all the living and non living factors in the environment A community of living organisms interacting with one another and with its non-living physical and chemical environment. Or An Ecosystem is a region in which living organism interact with their environment and these interactions perpetuate the community and retain stability under varying conditions.

2. Classification of ecosystem 3. Natural vs Artificial Ecosystem 4. Structure of ecosystem: Components 5. Producers Producers make their own food Green plants use energy from the sun to make food Producers are on the bottom of the food chain 6. Consumers Consumers hunt, gather, and store food because they cannot make their own. 7. Three Types of Consumers Herbivores Carnivores Omnivores 8. Herbivores Animals who eat plants such as: grasshoppers rabbits squirrels deer pandas 9. Carnivores (secondary consumers) Meat eaters and feed on herbivores are known as secondary consumers Eg dog, fox, wolf etc. 10. Carnivores (tertiary consumers) Carnivores which prey upon other carnivores but are not eaten themselves. They constitute the terminal end of predator of grazing food chain tigers lions hawks 11. Omnivores Animals who eat both plants and animals such as: humans bears 12. Decomposers Organism that feed on dead and decaying matter and convert the organic material in to organic material are called decomposers They help in nutrient recycling and known as recycling agent of the nature In absence of recycling nutrients earth would be converted in to a vast dump of dead organism Microorganisms that are able to break down large molecules into smaller parts 13. Abiotic components Physical factors: Sunlight, shade, intensity of solar flux, length of day , temperature, annual rainfall (precipitation), latitude, altitude, soil type, water availability Chemical factors: Availability of essential nutrients such as carbon, nitrogen, phosphorous, potassium, oxygen, sulfur, percentage of water and air in soil, salinity of water, oxygen dissolved in water 14. Functioning of Ecosystem The function of ecosystem can be studied in following terms Food chain Mineral nutrient cycle Energy flow 15. Food chain The transfer of food energy from the source through a series of organism by regular eating and eaten up In food chain each stage of transfer of food energy is known as trophic level Therefore trophic level refers to successive levels of energy flow that form the link of food chain 16. Types of Food Chains Aquatic- Water-related food chains with sea plants and animals Terrestrial- Land-related food chains with land plants and animals 17. Type of food chain Grazing food chain: Common in nature. Producer form the first link , herbivores as second and secondary consumer as the third Detritus food chain: The organic waste and dead matter derived from grazing food chain is termed as detritus. Detrivores are the animal that consume detritus and in doing so contribute to decomposition and recycling of nutrient Eg algea, bacteria, earthworms, millipedes Organism in this food chain are generally smaller, and functional role do not fall in catagories However grazing and detritus food chain are interlinked 18. Food webs It is not possible to depict the real world by means of simple food chain, because the interconnection between different trophic level in real world are extremely complex Various food chain are interlinked with each other and these interlocking pattern formed by several food chain linked together are called food web 19. Ecological Pyramids An ecological pyramid is a diagram that shows the relationship amounts of energy or matter contained within each trophic level in a food web or food chain. Energy Pyramid only 10% of the energy available within one trophic level is transferred to organisms at the next trophic level. 20. Pyramids Continued Biomass pyramids show the total amount of living tissue available at each trophic level. This shows the amount of tissue available for the next trophic level. Numbers pyramid shows the number of species at each trophic level. Because each trophic level harvests only about one tenth of the energy from the level below, it can support only about one 10th the amount of living tissue. 21. PYRAMID OF NUMBERS Shows the number of organisms at each trophic level per unit area of an ecosystem. 22. Pyramid of Numbers Pyramid of numbers displays the number of individuals at each level. 1 owl 25 voles 2000 grass plants 23. PYRAMID OF BIOMASS The total amount of matter present in organisms of an ecosystem at each trophic level is biomass. Biomass is preferred to the use of numbers of organisms because individual organisms can vary in size. It is the total mass not the size that is important. Pyramid of biomass records the total dry organic matter of organisms at each trophic level in a given area of an ecosystem. 24. Biomass PyramidsBiomass Pyramids Displays the biomass at each trophic level. 25. PYRAMID OF ENERGY Shows the amount of energy input to each trophic level in a given area of an ecosystem over an extended period. 1. Why will this type of pyramid never be inverted? 26. Energy PyramidEnergy Pyramid Fig. 419 In nature, ecological efficiency varies from 5% to 20% energy available between successive trophic levels (95% to 80% loss). About 10% efficiency is a general rule.