According to 10% law of Lindemann, the energy decreases at each trophic level of food chain, as part of the energy is lost as heat and respiration.
Only 10% chemical energy of previous trophic level is retained by next trophic level. The term ecosystem was first used by Tansley in 1935.
W.M. Stanley isolated TMV in crystals form. Weismann gave germ plasm theory.