Pyramids In Ecosystem
These are the graphic representations of trophic levels showing the relationship between different organisms in an ecosystem. There are three types of pyramids:
- Pyramid of number
- Pyramid of biomass
- Pyramid of energy
Pyramid of number– represents the number of organisms at each tropic level for example in grassland the number of grasses is more than the number of herbivores that feed on them and the number of herbivores is more than the number of carnivores.
In some instances, the pyramid of numbers may be inverted, i.e. Number of herbivores is more than primary producers observe that many caterpillars and insects feed on a single tree.
So, the number of organisms in each trophic level is considered as the level of pyramid.
Pyramid of biomass – In most of the terrestrial ecosystems the pyramid of biomass shown upright but in pond ecosystem, it may be found opposite as in the case of aquatic ecosystems the pyramid of biomass inverted e.g. in pond phytoplankton is the main producers, they have very short life i.e. they are rapidly replaced by new plants, here pyramid of biomass is inverted.
Pyramid of energy– represents the total amount of energy at each tropic level, it is expressed in rates as kcal/unit area /unit time or cal/unit area/unit time, Energy pyramids never found inverted.
ecological efficiency– ecological efficiency is the ratio between the amount of energy acquired from the lower trophic level and the amount of energy transferred from the higher tropic level. In 1942 Lindeman defined the ecological efficiencies for the 1st time and proposed a 10% rule e.g. if autotrophs produce 100 Cal, herbivores will be able to store 10 cal.
The importance of ecological pyramids: It shows the efficiency of the ecosystem and feeding of different organisms. By monitoring the ecosystem, prevention from future damage is possible.
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