Question

How is the only $10\%$ of energy passed from a trophic level to the next trophic level?

Answer 1

Hint: Food chain is an ecological sequence which resembles the transfer of matter and energy in form of food. A food chain can consist of three to four trophic levels. organisms are classified on the basis of their feeding habits. The first or the lowest trophic level consists of producers or plants.

complete answer:
The primary energy in the food chain is provided by the sun. The solar radiation absorbed by the primary producers are also known as autotrophs; these are considered on first trophic levels. Primary producers can be plants algae which perform photosynthesis and manufacture their own food. These are also known as autotrophs.
The rest of the trophic level is made up of consumers; these are known as heterotrophs as they cannot make their own food so they consume other organisms in order to acquire nutrition.
The second trophic level usually consists of herbivores that gain energy by consuming primary producers. These are consumed by secondary consumers and secondary consumers are consumed by tertiary consumers.
The energy in the food chain is transferred in a unidirectional manner. The amount of energy that is transferred to the next trophic level is only $10\%$ of energy as the rest of the energy is lost in metabolic processes as heat this is called the $10\%$ energy rule. For example, in a grassland ecosystem if it has 10,000 kcal of energy, only 1000 Kcal of energy will be transferred to the primary consumer and only 10 to the next level energy.

note:
The distribution can also be studied by the energy pyramid; this also represents the number of consumers in trophic level and the energy transfer.