What diagram illustrates the relative quantities of energy present at each trophic level in a food chain?

The diagram that illustrates the relative quantities of energy present at each trophic level in a food chain is the pyramid of energy. This type of pyramid represents the amount of energy that is available to each trophic level, typically measured in joules, and demonstrates that energy decreases as it moves up through the levels. This decrease occurs because energy is lost at each trophic level due to metabolic processes, heat loss, and inefficiencies in energy transfer (typically around 90% of the energy is lost at each level).

The concept behind the pyramid of energy is critical in understanding ecosystems since it highlights that there is a limit to how many trophic levels an ecosystem can support, based on the available energy from the primary producers at the base of the food chain. This makes it a fundamental tool for studying ecological relationships and energy flow within ecosystems.