A graphical representation of the biomass or bio-productivity at each trophic level in a given ecosystem is known as an ecological pyramid. Ecological pyramids start at the bottom with producers (such as plants) and work their way up through the trophic levels (such as herbivores that eat plants, then carnivores that eat flesh, omnivores that eat both plants and flesh, and so on). The apex of the food chain is the highest level. It can also be called trophic pyramid, Eltonian pyramid, energy pyramid, or food pyramid. This article will explain to you about Ecological Pyramids which will be helpful in preparing the Environment syllabus for the UPSC Civil service exam.

What is an Ecological Pyramid?

• A pyramidal representation of the link between different living species at different trophic levels in an ecological pyramid.
• G.Evylen Hutchinson and Raymond Lindeman were the ones who introduced it.
• These pyramids have a triangular shape of actual pyramids, with the base being the broadest and being covered by the lowest trophic level, i.e., producers.
• The next trophic level, i.e. the primary consumers and so on, occupies the following level.
• Since a sample space of a few numbers or a few species will result in a high degree of errors, all calculations for the creation of these sorts of ecological pyramids must take into consideration all creatures at a certain trophic level.

Ecological Pyramid

Types of Ecological Pyramid

Pyramid of Numbers

• The total number of individuals (population) present at each trophic level is represented by a pyramid of numbers.
• Elton John popularised the term "pyramid of numbers" in 1972.
• When it comes to counting the number of creatures, this pyramid is really efficient.
• Counting is a basic task that can be done over time to determine how an ecosystem has changed. However, some creatures, particularly young forms, are difficult to count.
• Except in rare cases, such as the detritus food chain, where many creatures feed on a single dead plant or animal, the number pyramid is normally vertical.

Pyramid of Numbers

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Pyramid of Biomass

• At a certain trophic level, biomass is the amount of living material present in an individual or a group of individuals per unit area product.
• Each level of this form of ecological pyramid accounts for the amount of biomass present in each trophic level.
• Except in oceans, where enormous numbers of zooplanktons rely on a relatively small number of phytoplankton, the biomass pyramid is also upright.

Pyramid of Biomass in Oceans

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Pyramid of Energy

• The energy pyramid is a vertical pyramid that depicts the transfer of energy from producers to consumers.
• As energy travels upwards, energy pyramids show how much energy is required in the next trophic level.
• As energy transmission in a food chain is always unidirectional, the energy pyramid is the only type of ecological pyramid that is always upright.
• In addition, as the trophic level rises, some energy is lost to the environment.

Pyramid of Energy

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Energy Flow in an Ecological Pyramid

• When one creature feeds another and obtains energy-rich molecules from its prey's body, energy is transmitted between trophic levels.
• However, these transfers are inefficient, and as a result, the length of food chains is limited.
• Some of the energy that enters a trophic level is stored as biomass, which is a component of organisms' bodies.
• As only energy stored as biomass can be eaten, this is the energy available to the next trophic level.
• As a general rule, only around 10% of the energy stored as biomass in one trophic level (per unit time) ends up being stored as biomass in the following trophic level (per unit time).
• The length of food chains is limited by this pattern of fractional transfer; after a certain number of trophic levels, usually three to six, there is insufficient energy flow to support a population at a higher level.

Energy Flow in an Ecological Pyramid

Limitations of the Ecological Pyramid

• As in the case of the food chain, several species may occupy multiple trophic levels.
• As a result, food webs are not taken into account by this system.
• Even though saprophytes are a significant feature of many ecosystems, they are not included in any of the pyramids.
• These pyramids are only useful for simple food chains that don't occur in nature.
• These pyramids don't provide any information about seasonal and climate changes.
• They don't take into account the possibility of many species existing at various levels.

Significance of Ecological Pyramid

The significance of the ecological pyramid can be expressed as follows:

• They illustrate the nutrition of several organisms in various habitats.
• It demonstrates the effectiveness of energy transmission.
• The ecosystem's state can be monitored, and any additional damage can be avoided.

Conclusion

In the three environmental pyramids, the pyramid of numbers is incorrect since it does not take into account the exact population. As a result, it is unable to fully describe the trophic structure of a system. However, the ecological pyramid as a whole is critical for discussing the concept of biological magnification, which is the tendency for harmful compounds to increase in quantity as trophic levels climb.