Ecological pyramids are graphical representations of the structure of ecosystems, showing the relative amounts of different components such as biomass, energy or numbers of individuals at each trophic level.The base of each pyramid represents the producers or the first trophic level while the apex represents tertiary or top level consumer.
There are three main types of ecological pyramids:
Pyramid of Numbers
- This type of ecological pyramid shows the number of individuals at each trophic level in an ecosystem. The pyramid of numbers is usually widest at the base, where the producers are located, and narrows at higher trophic levels.
Pyramid of Biomass
- This type of ecological pyramid shows the total amount of living matter, or biomass, at each trophic level in an ecosystem. Biomass is a more accurate measure of the amount of energy available to support life, as it takes into account the mass of living tissue at each trophic level.
- The pyramid of biomass is usually widest at the base, where the producers are located, and narrows at higher trophic levels.
Pyramid of Energy
- This type of ecological pyramid shows the amount of energy that flows through each trophic level in an ecosystem. The pyramid of energy is always upright, as the amount of energy available decreases as you move up the trophic levels.
- It’s important to note that the shape of the ecological pyramid can vary depending on the ecosystem being studied. For example, in some aquatic ecosystems, the pyramid of biomass may be inverted, with the biomass of phytoplankton (producers) being less than the biomass of zooplankton (consumers) due to the rapid turnover of phytoplankton.
- Additionally, in some ecosystems, such as grasslands, the pyramid of biomass may not match the pyramid of numbers due to differences in the size and mass of organisms at different trophic levels.
However, there are certain limitations of ecological pyramids such as it does not take into account the same species belonging to two or more trophic levels. It assumes a simple food chain, something that almost never exists in nature; it does not accommodate a food web. Moreover, saprophytes are not given any place in ecological pyramids even though they play a vital role in the ecosystem