AP BIOLOGY

Detailed explanation-1: -Energy decreases as it moves up trophic levels because energy is lost as metabolic heat when the organisms from one trophic level are consumed by organisms from the next level. Trophic level transfer efficiency (TLTE) measures the amount of energy that is transferred between trophic levels.

Detailed explanation-2: -Secondary and tertiary consumers, omnivores and carnivores, follow in the subsequent sections of the pyramid. At each step up the food chain, only 10 percent of the energy is passed on to the next level, while approximately 90 percent of the energy is lost as heat.

Detailed explanation-3: -Energy usually enters ecosystems from the Sun. The primary producers at the base of the pyramid use solar radiation to power photosynthesis which produces food.

Detailed explanation-4: -Within all biological communities, energy at each trophic level is lost in the form of heat (as much as 80 to 90 percent), as organisms expend energy for metabolic processes such as staying warm and digesting food (see biosphere: The organism and the environment: Resources of the biosphere: The flow of energy).

Detailed explanation-5: -Not all the energy is passed from one level of the food chain to the next. About 90 per cent of energy may be lost as heat (released during respiration), through movement, or in materials that the consumer does not digest. The energy stored in undigested materials can be transferred to decomposers.