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FUNCTIONS OF AN ECOSYSTEM.pptx

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Ecology and ecosystems
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FUNCTIONS OF AN ECOSYSTEM.pptx

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An ecosystem is a system consisting of biotic and abiotic components that function together as a unit. The biotic components include all the living things whereas the abiotic components are the non-living things. Thus, an ecosystem is an ecological community consisting of different populations of organisms that live together in a particular habitat.
Fundamentally, ecosystem functions are exchange of energy and nutrients in the food chain. These exchanges sustain plant and animal life on the planet as well as the decomposition of organic matter and the production of biomass. This presentation contains the major functions of an Ecosystem

An ecosystem is a system consisting of biotic and abiotic components that function together as a unit. The biotic components include all the living things whereas the abiotic components are the non-living things. Thus, an ecosystem is an ecological community consisting of different populations of organisms that live together in a particular habitat.
Fundamentally, ecosystem functions are exchange of energy and nutrients in the food chain. These exchanges sustain plant and animal life on the planet as well as the decomposition of organic matter and the production of biomass. This presentation contains the major functions of an Ecosystem

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FUNCTIONS OF AN ECOSYSTEM.pptx

  1. 1. DEVIKA DAS DC 3 BIOTECHNOLOGY
  2. 2. Ecosystem An ecosystem is a system consisting of biotic and abiotic components that function together as a unit. The biotic components include all the living things whereas the abiotic components are the non-living things. Thus, an ecosystem is an ecological community consisting of different populations of organisms that live together in a particular habitat.
  3. 3. Functions of an ecosystem : The functional attributes of the ecosystem keep the components running together. Ecosystem functions are natural processes or exchange of energy that takes place in various plant and animal communities of different biomes of the world. It can be studied under the following three heads- • Energy flow • Nutrient cycling (biogeochemical cycles) • Ecological succession
  4. 4. 1.Energy flow • Energy is the basic force responsible for all metabolic activities. The flow of energy from producer to top consumers is called unidirectional energy flow. • The study of Trophic level interaction in an ecosystem gives an idea about the energy flow through the ecosystem. Trophic level interaction Trophic level interaction deals with how the members of an ecosystem are connected based on nutritional needs.
  5. 5. Following trophic levels can be identified in a food chain. • Autotrophs: They are the producers of food for all other organisms of the ecosystem. They are largely green plants and convert inorganic material in the presence of solar energy by the process of photosynthesis into chemical energy (food). • Herbivores: The animals which eat the plants directly are called primary consumers or herbivores e.g. insects, birds, rodents and ruminants. • Carnivores: They are secondary consumers if they feed on herbivores and tertiary consumers if they use carnivores as their food. e.g. frog, dog, cat and tiger. • Omnivores: Animals that eat both plant and animals e.g. pig, bear and man • Decomposers: They take care of the dead remains of organisms at each trophic level and help in recycling the nutrients e.g. bacteria and fungi.
  6. 6. Energy flows through the trophic levels from producers to subsequent trophic levels. This energy always flows from lower {producer) to higher (herbivore, carnivore, etc.) trophic level. It never flows in the reverse direction that is from carnivores to herbivores to producers. There is a loss of some energy in the form of unusable heat at each trophic level so that energy level decreases from the first trophic level upwards.
  7. 7. The trophic level interaction involves three concepts namely: • Food Chain • Food Web • Ecological Pyramid
  8. 8. A. Food Chain Transfer of food energy from green plants (producers) through a series of organisms with repeated eating and being eaten is called a food chain. e.g. Grasses → Grasshopper → Frog → Snake → Hawk/Eagle
  9. 9. B. Food Web Trophic levels in an ecosystem are not linear rather they are interconnected and make a food web. Thus, the food web is a network interconnected food chains existing in an ecosystem. One animal may be a member of several different food chains. Food webs are more realistic models of energy flow through an ecosystem.
  10. 10. C. Ecological Pyramid Ecological pyramids are the graphic representations of trophic levels in an ecosystem. They are pyramidal and they are of three types: The producers make the base of the pyramid and the subsequent tiers of the pyramid represent herbivore, carnivore and top carnivore levels.
  11. 11. The ecological pyramids are of three categories • Pyramid of numbers : This represents the number of organisms at each trophic level
  12. 12. • Pyramid of biomass : This represents the total standing crop biomass at each trophic level. Standing crop biomass is the amount of the living matter at any given time. It is expressed as gm/unit area or kilo cal/unit area
  13. 13. • Pyramid of energy or productivity : This pyramid represents the total amount of energy at each trophic level. Energy is expressed in terms of rate such as kcal/unit area /unit time or cal/unit area/unit time. E.g. in a lake autotroph energy is 20810 kcal/m/year. Energy pyramids are never inverted.
  14. 14. 2. Nutrient cycling (biogeochemical cycles) • The ways in which an element—or compound such as water—moves between its various living and nonliving forms and locations in the biosphere is called a biogeochemical cycle. • Biogeochemical cycles important to living organisms include the water, carbon, nitrogen, and phosphorous cycles.
  15. 15.  The water cycle The water cycle is driven by the Sun’s energy. The sun warms the ocean surface and other surface water, causing liquid water to evaporate and ice to sublime—turn directly from a solid to a gas. These sun-driven processes move water into the atmosphere in the form of water vapor. Over time, water vapor in the atmosphere condenses into clouds and eventually falls as precipitation, rain or snow. When precipitation reaches Earth's surface, it has a few options: it may evaporate again, flow over the surface, or percolate—sink down—into the ground.
  16. 16.  The Carbon Cycle Carbon cycle is the process where carbon compounds are interchanged among the biosphere, geosphere, hydrosphere, and atmosphere of the earth. Following are the major steps involved in the process of the carbon cycle:  Carbon present in the atmosphere is absorbed by plants for photosynthesis.  These plants are then consumed by animals and carbon gets bio accumulated into their bodies.  These animals and plants eventually die, and upon decomposing, carbon is released back into the atmosphere.  Some of the carbon that is not released back into the atmosphere eventually become fossil fuels.  These fossil fuels are then used for man-made activities, which pumps more carbon back into the atmosphere.
  17. 17.  The Nitrogen Cycle • Fixation - Fixation is the first step in the process of making nitrogen usable by plants. Here bacteria change nitrogen into ammonium. • Nitrification - This is the process by which ammonium gets changed into nitrates by bacteria. Nitrates are what the plants can then absorb. • Assimilation - This is how plants get nitrogen. They absorb nitrates from the soil into their roots. Then the nitrogen gets used in amino acids, nucleic acids, and chlorophyll. • Ammonification - This is part of the decaying process. When a plant or animal dies, decomposers like fungi and bacteria turn the nitrogen back into ammonium so it can reenter the nitrogen cycle. • Denitrification - Extra nitrogen in the soil gets put back out into the air. There are special bacteria that perform this task as well.
  18. 18.  The phosphorus cycle Phosphorus moves in a cycle through rocks, water, soil and sediments and organisms. • Over time, rain and weathering cause rocks to release phosphate ions and other minerals. This inorganic phosphate is then distributed in soils and water. • Plants take up inorganic phosphate from the soil. The plants may then be consumed by animals. Once in the plant or animal, the phosphate is incorporated into organic molecules such as DNA. When the plant or animal dies, it decays, and the organic phosphate is returned to the soil. • Within the soil, organic forms of phosphate can be made available to plants by bacteria that break down organic matter to inorganic forms of phosphorus. This process is known as mineralisation. • Phosphorus in soil can end up in waterways and eventually oceans. Once there, it can be incorporated into sediments over time.
  19. 19. Ecological succession, the process by which the structure of a biological community evolves over time. Two different types of succession—primary and secondary—have been distinguished. • Primary succession occurs in essentially lifeless areas—regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. • Secondary succession occurs in areas where a community that previously existed has been removed; it is typified by smaller-scale disturbances that do not eliminate all life and nutrients from the environment. 3. Ecological succession or ecosystem development
  20. 20. ECOLOGICAL SUCCESSION :

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