1. In a food chain as we move from producers to different levels of consumers the energy available will decrease gradually.
2. Only ten percent of the energy present in one tropic level transfer to another tropic level.
3. Biomass also decreases gradually as only 10 – 20% of the biomass is transferred from one tropic level to the next in a food chain.
4. As there is less energy of less biomass available at top levels, number of organisms also less generally.
5. So the number of organisms get decreased as we move from producers to different level of consumer.