Q.In a grassland ecosystem an organism of (T3) third trophic level derives 400 joules of energy. How much energy would be there in first trophic (T1) level ? Calculate.

Energy flow is the transfer of energy between successive trophic levels in an ecosystem, and it is the ecosystem's single most important function. Energy captured by a producer moves on to consumers and then decomposers step by step, losing some as heat at every single transfer, and — critically — this flow runs in one direction only, never reversing. Two thermodynamic laws govern it. The first law of thermodynamics states energy is never created or destroyed, only transformed from one form to another (e.g. light energy converted into the chemical energy of starch during photosynthesis, with the total quantity of energy unchanged). The second law of thermodynamics states that every energy transformation reduces the system's usable (free) energy and is never 100% efficient — as food energy passes between organisms, part is retained as living tissue while a large share is irreversibly dissipated as heat through respiration. This second-law loss is captured precisely by Lindeman's (1942) ten percent law: at each trophic transfer only about 10% of the energy is retained by the receiving level, with the remaining …