Question

Why only 10% of energy and mass is transferred to the next level in a food chain?

Answer 1

Hint: All organisms acquire energy from the food that they consume. Energy is essential for the growth, development and maintenance of the organisms. Energy is transferred from one organism to another in the form of a food chain. During the transfer process, only $10\% $ of the total energy is transferred from one organism to another. This law is known as the $10\% $ energy law and was proposed by Raymond Lindeman.

Complete explanation:
In a food chain, each biological organism occupies a particular trophic level. There are four trophic levels in a food chain namely- producers, primary consumers, secondary consumers and tertiary consumers.
The producers are the plants and they obtain their energy from the sun. Plants are consumed by primary consumers and they do not acquire $100\% $of the energy from them since some of the sun energy is used by plants during photosynthesis. Only $10\% $ of the total energy is passed onto the primary consumers. Similarly, $1\% $ and $0.1\% $ of energy are transferred to secondary and tertiary consumers respectively.
The energy is lost during energy transfer, broken down in respiration or lost in incomplete digestion. The $10\% $ energy law says that exactly $90\% $ of the energy is lost during transfer and only $10\% $ of the energy is passed on as usable energy.

Note:
The flow of energy from one trophic level to another is represented by an energy pyramid. The ten percent energy law is not much accepted in the scientific community due to its misleading preciseness. Some label this law as myth because in nature not everything is in a fixed and ordered state.This ten percent value is also not fixed and it varies with different types of ecosystems.