What is an Ecological Pyramid?
The ecological pyramid is also known as a food pyramid or trophic pyramid or energy pyramid and even the Eltonian pyramid as the concept of such pyramids which depict numbers was proposed by Charles Elton in the year 1927.
Then came Bodenheimer in 1938 who proposed the pyramid structure for biomass and in 1942 Hutchinson and Linderman proposed the pyramid for productivity.
The pyramid is framed based on the number of individuals, energy, and biomass, and very much like the name recommends, these are shaped as a pyramid. The various kinds of ecological pyramids depend on how much energy or biomass or individuals are accessible to each trophic level.
The bottom of the pyramid, usually the broadest part is occupied by the producers followed by the primary consumers at the next level, then the secondary consumers, and then tertiary consumers or the organisms placed at the top of the food chain at the topmost level.
The ecological pyramid is additionally used to make sense of how different living beings in an environment are connected with each other. Also, it shows who is consumed by whom, while likewise showing the flow of the energy.
Features of the Ecological Pyramid
The following are the characteristics of an Ecological Pyramid:
The ecological pyramid comprises two to four layers.
Organisms that are dependent on the same type of food sources are placed at the same level.
The producers are situated at the lowest level of an ecological pyramid with a huge population.
The apex predators exist at the topmost level of an ecological pyramid with a relatively smaller population.
The pointed shape of the pyramid is due to the fact that the supply of energy or biomass becomes lesser with each passing level of the pyramid.
In the case of the pyramid of numbers, the topmost level will have a lesser number of individuals but their relative body size and volume increase.
Types of Ecological Pyramid
The ecological pyramid is of three types; the pyramid of numbers, the pyramid of biomass, and the pyramid of energy.
Pyramid of Number
The ecological pyramid that is made by organizing the number of living individuals at various trophic levels in an ecological system is known as the pyramid of numbers with producers at the base and top carnivores at the topmost level.
The pyramid of numbers can be both upright and inverted.
The upright pyramid has the largest number of producers at the base and their numbers keep on declining with each passing level like pond or grassland ecosystem.
In the inverted pyramid, the base pointed with a lesser number of producers whereas the topmost level will have the largest number of individuals as the size and food consumption of organisms in each level will decrease i.e. in this system one individual producer can support many primary consumers, similarly, one primary consumer can support many secondary consumers, and so on. This type of pyramid is seen in the case of a parasitic food chain.
Pyramid of Biomass
The ecological pyramid that is made by considering the amount of biomass that is produced by the living system of each trophic level is represented by the pyramid of biomass. The pyramid that demonstrates the total weight of every trophic level in a specific food chain in an ecosystem is the biomass pyramid.
Like the pyramid of numbers, the pyramid of biomass can be both upright and inverted.
Forests and grasslands ecological systems are instances of upstanding biomass pyramids as the number of producers is more in number.
The ocean ecosystem is an example of an inverted pyramid as a large number of zooplankton are dependent on a lesser number of phytoplankton. Dependent on the trophic level of an ecosystem, only 15 to 20% of biomass per level goes to the following level.
Pyramid of Energy
The ecological pyramid which is formed by determining the flow of energy from one trophic level to another is known as the pyramid of energy. The producers situated at the base of the pyramid of energy have the highest amount of energy and the topmost consumer at the top has the least amount of energy.
The pyramid of energy is always upright. This pyramid addresses the complete energy content of each trophic level in an ecological system.
The base of this pyramid i.e. producers has the most amount of energy acquired from the sun fixed by the help of photosynthesis.
The flow of energy in this pyramid proves that energy can neither be created nor can be destroyed given by the law of thermodynamics.
However, as indicated by Lindeman’s 10% regulation law, only 10% of the energy gets transferred from one level to another as almost the 90% is lost as heat energy is used in breathing, some are utilized in physiological cycles, and the rest is utilized by decomposers.