Final answer:
Most of the energy in a food chain is concentrated at the level of the producers, which are the first trophic level in an energy pyramid. Energy loss at each step means only about 10 percent of energy is passed to the next level, leading to fewer organisms and less energy as one moves higher up the food chain.
Step-by-step explanation:
Energy Concentration in Food Chains.Most of the energy in a food chain is concentrated in the level of the producers, which occupy the first trophic level at the bottom of the energy pyramid. In ecological terms, producers, like plants and photosynthetic organisms, convert solar energy into chemical energy through the process of photosynthesis, providing the base for the energy that flows through the rest of the food chain. As energy moves up to higher trophic levels, such as to primary consumers (herbivores), and then to higher-level consumers (carnivores and apex predators), the amount of energy available decreases due to energy being used for metabolic processes and released as heat.
Because of this energy loss, typically only about 10 percent of the energy is transferred from one trophic level to the next. Consequently, higher trophic levels have less energy available, which is why food chains rarely have more than four or five levels. This phenomenon also explains why ecosystems cannot sustain a large number of trophic levels.