Final answer:
An energy pyramid shows the decreasing amount of energy available at successive trophic levels, with producers at the base and carnivores at the top. Approximately 10% of energy is transferred from one level to the next, while the rest is lost to metabolism and heat.
Step-by-step explanation:
An energy pyramid visually represents the energy that is present at different trophic levels in an ecosystem and how it decreases as energy is transferred from one level to the next. Starting with the producers at the base, which in our example have 1,000,000 kilocalories of energy, the energy available to the primary consumers (herbivores) would typically be about 10% of that, due to energy loss in metabolic processes and heat dissipation.
Trophic levels and biomass are key concepts that describe the structure and energy flow in ecosystems. With less energy at higher trophic levels, there tends to be a decrease in biomass, meaning less total mass of organisms, and usually fewer numbers of larger organisms like carnivores. Consequently, these pyramids are always upright, illustrating that a large number of organisms at the bottom are needed to support a relatively small number of top carnivores.
The energy not transferred to the next trophic level is often utilized for metabolic activities or lost as heat to the environment, explaining why energy pyramids rarely exceed four or five levels. For example, only about 10% of the energy from the producers is passed on to herbivores, and from herbivores to carnivores, with each successive level.