A graphic depiction of the interactions between various creatures in an ecosystem is called an ecological pyramid. The Eltonian Pyramids, named after Charles Elton, are another name for them. The trophic levels represented by each of the horizontal bars that make up the pyramid are different, and their arrangement—which is determined by who eats whom—represents the flow of energy.
Energy Flow in An Ecosystem is governed by the following laws:
Energy cannot be generated or destroyed, according to the First Law of Thermodynamics, but it can be changed from one form to another.
The Second Law of Thermodynamics asserts that the amount of available energy rapidly decreases with each subsequent energy transfer in a system.
As an example, during the movement of food energy throughout an ecosystem, a significant portion is lost as heat as a result of metabolic processes. Only a limited portion is stored in biomass or living tissues.
Three types of ecological pyramids exist in nature-
Of which all are upright without any exceptions as energy flow in all the ecosystems follows the 10% law of energy at each stage.
Pyramid of Numbers
The population density at each trophic level is represented by the pyramid of numbers. Let’s say that each day, an ecosystem obtains 1000 calories of light energy. Only 100 of the 1000 calories are retained as energy-rich materials since the majority of the energy is not absorbed, some of it is reflected in space, only a small portion is used by green plants, and of those, the plant uses up some for respiration. Now imagine that a deer or another animal consumes the plant that has 100 calories of dietary energy. A portion of it is used by the deer for metabolism, and just 10 calories are stored as food energy. Even less energy is gained by a lion that consumes the deer. Thus, from sunlight to producer to herbivore to carnivore, useful energy diminishes. The energy pyramid will always be upright as a result.
The number pyramid is typically upright, with the exception of some circumstances like the detritus food chain, in which numerous species consume a single dead plant or animal. Elton came up with the phrase “Pyramid of numbers” for the first time in 1972.
Because of food waste during eating, digestion, and finally, the utilization of food for respiration and physical activity, the population of people living in higher tropics typically continues to decline.
The pyramid of numbers has certain limits, though, since it doesn’t account for the precise population. As a result, it is unable to fully describe the trophic structure of a system, overlooks species biomass, and obscures the flow of energy between individuals. Number pyramids are not particularly useful since they do not provide a clear or accurate representation of the food chain.
Pyramid of Biomass
Indicating the total mass of organisms at a certain trophic level, biomass is the amount of living material per unit area present in an individual or a group of individuals at a given trophic level. Each level of this specific ecological pyramid considers the amount of biomass that each trophic level produces. With the exception of what is seen in oceans, where numerous zooplanktons depend on a relatively small number of phytoplanktons, the biomass pyramid is also vertical.
The pyramid typically starts out larger at the base and gets smaller as it rises. A rise in trophic levels invariably results in a decrease in biomass. Approximately 10 and 20 percent of the biomass is transferred from one trophic level to another.
Inverted and upright pyramids are the two forms of biomass pyramids. One is the aquatic ecology, where microscopic phytoplanktons with a very high number but very little biomass serve as producers.
The terrestrial environment is represented by the upright pyramid. The smallest trophic levels are found at the top, and it has a broad base made up primarily of primary eaters.
The advantage of this pyramid is that it shows the amount of energy at each trophic level precisely. When there is a drop in biomass and a rise in trophic levels, it shows waste and consumption of biomass at every transfer level. This pyramid has the advantage of accurately depicting the quantity of energy present at each trophic level. It indicates waste and consumption of biomass at every transfer level when there is a decrease in biomass and an increase in trophic levels. However, there are certain constraints that surround this pyramid as well, such as the fact that it is actually difficult to quantify the mass of every single person. Since only a sample is taken, mistakes might occur, and various species have distinct breeding seasons.
Pyramid of Energy
The transfer of energy from producers to consumers is depicted by the upright pyramid known as the “pyramid of energy.” It reveals the actual part different species actually play in the flow of energy. Energy pyramids show how much energy is needed as it moves up the trophic levels. Since energy transmission in a food chain is always unidirectional, the pyramid of energy is the only sort of ecological pyramid that is always upright. Also, some energy is lost to the environment at each higher trophic level. This energy pyramid is based on Lindemann’s idea of the movement of energy in a food chain.
The energy is highest at the producer level and gradually decreases as it moves to the subsequent levels, including herbivores (primary consumers), carnivores (secondary, tertiary consumers)
How Ecological Pyramids Help in understanding the Environment
In addition to displaying the eating habits of creatures in various environments, an ecological pyramid can also demonstrate the inefficiency of energy transfer and the effects that changes in the population of one trophic level might have on the trophic levels above and below it.
Second, it is beneficial to see how the organisms are affected by environmental changes.
Additionally, it aids the government in taking the required actions to protect ecosystems from harm and perhaps even undo some of the current harm.