Answer:
Food chain is diagrammatic representation of hierarchical series of organisms from producers to top consumers.
- For example, aquatic food chain may comprise of zooplankton, fresh water shrimp, minnow, perch, pike and osprey.
- In case, if the population size of perch is decreased then eventually there will be an increase in the population of its prey or organisms which are at lower trophic level than perch. For example, population of minnow in this will increase.
- However, increased minnow population will eat more and more shrimps and after some time due to shortage of food they will start dying. By this process they will maintain the equilibrium with shrimp population.
- In contrast, decreased perch population will have a negative effect on the organisms of upper trophic levels as they will die of starving unless they find any other food source.
Food web represents the interaction of two or more food chains.
- It is the reason that population change of single species may or may not affect other species in the food web.
- If one species is decreased or extinct then other species might be available to take play its role.
- For example, Pike fish in this case start eating other fishes such as burbot, sunfish etc.
