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 law of thermodynamics speaks in volumes about the distribution of energy on our planet. Being the primary source of energy for planet Earth, the Sun provides the energy essential for all the lifeforms on the planet. This energy is derived by all these lifeforms either directly or indirectly. This is exactly the concept on which energy pyramid definition stresses when it says that it is the graphical representation of the trophic levels by which solar energy is transferred in the ecosystem.

What is an Energy Pyramid?

Simply put, all the living organisms on the planet can be broadly categorized into four groups - the primary producers (plants), primary consumers (herbivores), secondary consumers (primary carnivores) and the tertiary consumers (secondary carnivores). 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 Sun's energy which is stored in plants, and when the carnivores feed on herbivores they derive this energy from the herbivores. Secondary carnivores also feed on primary carnivores, and hence are located at the top of the food chain.

How Does an Energy Pyramid Work?

In a healthy ecosystem, the number of primary producers easily overshadow the number of primary, secondary or 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 a given ecosystem is known as the energy pyramid or the ecological pyramid. Imagine the graphical representation of this concept in form of a diagram. The plants or primary producers, with highest concentration, will form the base of the pyramid, while the carnivores, with the least concentration, form its apex. There also exist the detritivores, i.e. the lifeforms which feed of dead plants and organisms. These detritivores break down complex organic matter and add it to the soil, only to be used by the autotrophs as nutrients eventually.

Tropical Rainforest Example

The intricacies involved in this concept is likely to make it difficult for a lay person to understand it. That being said, going through an example of a food chain will make the concept relatively easier to understand. Being one of the richest biomes of the world, the South American tropical rainforests would be the best example of energy pyramid.

When it comes to the tropical rainforests, various tropical rainforest plants form the base. Herbivorous animals, such as the capybara, tend to feed on these plants, and derive energy from them. Eventually, primary carnivores, such as the ocelot feed on herbivores and get the required amount of 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 get decomposed by bacterial activity and get mixed into the soil. When new plants grow, they derive nutrients from this very soil and the entire tropical rainforest food web cycle starts all over again.

The intricacies of these energy 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 in the rainforests results in a rise in capybara population. These capybaras will feed on plants available in this region, and that will result in depletion of the green cover in this region. This is very well possible, and we also have quite a few examples of the same which makes it all the more important to stress on conservation of the nature.