Which type of ecological pyramid is always upright?

A pyramid of energy is always upright because it represents the flow of energy through the different trophic levels in an ecosystem. Energy is transferred from one trophic level to the next, and with each transfer, there is a significant loss of energy, typically around 90%, due to metabolic processes, heat loss, and other factors. As a result, the energy available at the primary producers level is much greater than that available to primary consumers, and this pattern continues consistently through the higher trophic levels. Therefore, the shape of the pyramid reflects this structure, with the base representing a large amount of energy (from producers) and the top levels showing progressively smaller amounts of energy (with predators at the top). This consistent decrease ensures that the pyramid remains upright.

In contrast, the other types of ecological pyramids can sometimes have inverted structures. For example, a pyramid of numbers may be inverted if a few producers support a large number of primary consumers, and a pyramid of biomass can also be inverted under certain circumstances, such as in ecosystems where a higher biomass of secondary consumers may exist compared to primary producers at a given time. A pyramid of productivity, while typically upright due to the nature of energy flow, can vary based on specific ecosystem dynamics but is less