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DDT was sprayed in a lake to regulate breeding of mosquitoes. How would it affect the trophic levels in the following food chain associated with a lake? Justify your answer.OR In the following food chain, vertical arrows indicate the energy lost to the environment and horizontal arrows indicate energy transferred to the next trophic level. Which one of the three vertical arrows (A, C and E) and which one of the two horizontal arrows (B and D) will represent more energy transfer? Give reason for your answer. |
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Answer» ● DDT being a non- biodegradable pesticide will enter the food chain from the first trophic level i.e Plankton. ● Non – biodegradable pesticides accumulate progressively at each trophic level. This phenomenon is known as biological magnification. ● HAWK will have the highest level of pesticide. OR A will represent more energy transfer as compared to C and E. B will represent more energy transfer as compared to D. When green plants are eaten by primary consumers, a great deal of energy is lost as heat to the environment, some amount goes into digestion and in doing work and the rest goes towards growth and reproduction. An average of 10% of the food eaten is made available for the next level of consumers. This loss of energy takes place at every trophic level. Alternatively accept - In accordance with 10% law of transfer of energy in a food chain only 10% of energy available at one trophic level is transferred to the next trophic level. |
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