An ecological pyramid is a graphical representation of an ecological parameter like number, biomass, and energy depicted in a systematic and stepwise manner in an ecosystem. Each of the steps represents each of the tropic levels. The concept of ecological pyramids was developed in 1927 by Charles Elton. They were originally called as Eltonian pyramids.$^1$
There are three types of pyramids that can be formed from the ecosystem are: $^1$
This pyramid deals with the relationship between the number of primary produces and consumers of a different order(different tropic levels).$^1$
This is an example of an upright pyramid of numbers
Energy is lost to the surroundings as we go from one level to the next, so there are fewer organisms at each level in this food chain.$^1$
When the initial producers is large, like trees, the pyramid of numbers will not look like a pyramid at all. For example, take the food chain Oak tree → insects → woodpecker. This is an inverted pyramid, as Oaktree is one and that is producer. There will be 10-12 birds on this plant that are fruit eating, primary consumers. Next there will be several parasites on those bird’s body, secondary consumers. There will be hyper-parsites, tertiary consumer. The population of each of the tropic levels increase. Hence making the ecological pyramid inverted.$^1$
This pyramid explains the biomass per unit area.$^1$
The pyramid of biomass in a grassland ecosystem is upright. The producers are grasses. The primary consumers are rabbits, rats, mice, etc.$^1$
An example of an inverted pyramid of biomass exist in the ocean. The biomass of carnivores or the secondary consumers, example sharks, is high compared to the producers and herbivores(primary consumers). Therefore the amount of biomass is largest at the top of the pyramid, and is comparatively low at the lower tropic levels.$^1$