The amount of energy transferred from one trophic level to the next in an ecosystem is typically around 10 percent. This is known as the 10% rule. According to this rule, only about 10% of the energy available in a given trophic level is passed on to the next trophic level, while the remaining 90% is lost as heat or used for metabolic processes by the organisms in that level. This means that as we move up the food chain, the amount of available energy decreases significantly. For example, if there is 100 units of energy available to primary producers (plants), only about 10 units of energy would be transferred to the primary consumers (herbivores), and so on. This energy transfer efficiency is mainly due to metabolic inefficiencies, such as energy lost as heat during respiration and digestion, as well as incomplete digestion and absorption of food.
