What is an Energy Pyramid?

The first Law of Thermodynamics states that 'energy can neither be created nor be destroyed, it can be only transferred from one form to another'. This speaks volumes about the distribution of energy on our planet. Being the primary source of energy, the Sun provides it to all the lifeforms on the planet.

The lifeforms derive this energy either directly or indirectly. Based on this concept, the energy pyramid is defined as 'the graphical representation of the trophic levels by which solar energy is transferred in the ecosystem.'

All the living organisms on the planet can be broadly categorized into four groups: primary producers, primary consumers (herbivores), secondary consumers (primary carnivores), and tertiary consumers.

Being photosynthetic in nature, plants have the ability to absorb the radiations from the Sun and utilize them.

When the herbivores feed on these plants, they derive the energy that is stored in plants, and when the carnivores feed on herbivores, the same is passed on to them. Secondary carnivores also feed on primary carnivores and thus, are located at the top of the food chain.

In a healthy ecosystem, the number of primary producers easily overshadows the number of primary, secondary, and tertiary consumers. In fact, the number of tertiary consumers is always the least in a given ecosystem. This is exactly the reason why distribution of energy in the ecosystem is known as the energy pyramid or ecological pyramid.

Then there exist the detritivores, i.e., the lifeforms which feed of dead plants and organisms. They break down complex organic matter and add it to the soil, which is eventually used by the autotrophs (plants) as nutrients.

When it comes to tropical rainforests, tropical plants play the role of primary producers. Herbivorous animals, such as the capybara, feed on these plants and derive energy from them.

In turn, primary carnivores, such as the ocelot, feed on herbivores and get the required energy from them. Similarly, secondary carnivores, such as the jaguar (which are also the apex predators), feed on herbivores as well as primary carnivores, and derive energy from them.

When any of these animals die, they decompose as a result of bacterial activity and get mixed in the soil. When new plants grow, they derive nutrients from this very soil and the entire cycle starts all over again.

The intricacies of these pyramids are such that a slight disturbance at any level can result in chaos in the entire structure. For instance, a fall in ocelot and jaguar population will result in a rise in capybara population. These capybaras will feed on plants available in this region, which will result in depletion of the green cover.