2.2.8—Second law and energy loss
- Syllabus
- First assessment 2026
- Objective
- 2.2.8
- Level
- SL
The Second Law Explains Falling Efficiency
Every energy transformation disperses some concentrated, usable energy as heat, so ecosystem transfers are never 100% efficient.
The first law tracks total energy conserved; the second law explains why its ability to do biological work declines. They describe different aspects, not contradictions.
A plant’s stored chemical energy becomes herbivore biomass, movement and heat; only the biomass portion reaches the next level.
No. It says useful energy becomes more dispersed and less available for work.
Do not confuse conserved total energy with conserved usable energy.