2.2.29 (HL)—Entropy in ecosystems

Each energy transfer disperses some usable energy as heat, increasing entropy and leaving less available for work.

Energy is conserved, but its concentration and usefulness change. Respiration, friction and decomposition spread energy into the surroundings.

A 100 kJ food input may yield 20 kJ of new biomass and roughly 80 kJ dissipated through metabolism and waste.

No. It remains energy, but is more dispersed and less available to drive another trophic transfer.

The second law does not contradict conservation of energy; it limits how much remains concentrated and useful.