AP BIOLOGY

Detailed explanation-1: -The amount of energy at each trophic level decreases as it moves through an ecosystem. As little as 10 percent of the energy at any trophic level is transferred to the next level; the rest is lost largely through metabolic processes as heat.

Detailed explanation-2: -The reason for this is that only around 10 per cent of the energy is passed on to the next trophic level. The rest of the energy passes out of the food chain in a number of ways: it is released as heat energy during respiration. it is used for life processes (eg movement)

Detailed explanation-3: -On average, only about 10% of the energy stored as biomass in one trophic level-e.g., primary producers-gets stored as biomass in the next trophic level-e.g., primary consumers. Put another way, net productivity usually drops by a factor of ten from one trophic level to the next.

Detailed explanation-4: -The ten percent rule states that each trophic level can only give 10% of its energy to the next level. The other 90% is used to live, grow, reproduce and is lost to the environment as heat. All energy pyramids start with energy from the Sun which is transferred to the first trophic level of producers.