Concept : Energy Pyramid
An energy pyramid is a model that shows the flow of energy from one trophic level to another trophic level in a food chain.
Features of an Energy Pyramid
- The energy in an energy pyramid is measured by kilocalorie (kcal) and joule (J).
- The structure of an energy pyramid resembles the trophic structure of an ecosystem.
- The energy pyramid is divided into trophic levels similar to a food chain.
- The pyramid base represents green plants which are autotrophs.
- The organisms at other trophic levels are consumers.
- The energy pyramid is broad at the base, narrowing while going upwards.
- It depicts that the energy at the first trophic level is maximum, decreasing as one moves up in a food pyramid.
10 % rule in Energy Pyramid:
It means that only 10 percent of available energy is passed to the next
trophic level, and 90 percent is lost in the environment through metabolic
processes as heat. This is also called Lindemann’s law of 10%.
Example:Let us assume a grassland
ecosystem has 10,000 J of energy. Then as per the 10% rule,
1,000 J of energy will get transferred to the primary consumers, and as little as 10 J of energy will be transferred to the tertiary consumers.
Grassland ecosystem: It is a community of living organisms, including insects, birds, and animals, living in an open grassy space.
Metabolic processes: The processes in a living organism that are important for survival like respiration, digestion, excretion, reproduction, etc.
Increase or decrease in the number of an organism does not affect the
Increase or decrease in the number of an organism does affect the food chain because it creates an imbalance. For example, an increase in the number of deer would impact the population of green plants. Similarly, an increase in the number of carnivores would impact the number of herbivores.
Omnivores get more energy as they eat both plants and animal:
The amount of energy an omnivore receives depends on the trophic level which it occupies.
If the organism lies in the second trophic level, it will receive more energy than the energy it will receive when it is in the third or fourth trophic level.