Indicate the flow of energy in an ecosystem. Why is it unidirectional? Justify.

The energy flow is from one trophic level to another i.e. from producer to primary consumer to secondary consumer to tertiary consumer. The direction of flow of energy is in one direction i.e. it is unidirectional. It is not possible that energy flow occurs in opposite direction or in reverse direction. For example: a Predator can eat a prey but its reverse is not possible. Moreover, once the energy utilized by the organisms in food chain can’t be revert back to the sun. Similarly, the energy once used by carnivores can’t be revert back to herbivores which means that the flow of energy in an ecosystem is unidirectional in ecosystem.