Question

What happens in the food pyramid?

Answer 1

Energy lost as heat energy; only approximately 10% of stored energy in prey pass to the consumer.

Explanation:

As a rule of thumb, preys are consumed by hunters or consumers. If prey has 10 units of energy, only 10% of it pass to the hunter or consumer.

Most of the energy is lost due to not used parts of prey, energy to find prey, effort to catch prey, etc.

It means when you go to upper part in a food chain (or pyramid), less energy pass to the upper consumers.

An example:

Apple `->` apple consumer
10 units of energy `->` 1 unit of energy

Anoher one: Apple `->` Cow `->` Human
10 units of energy `->` 1 unit of energy `->` 0.1 unit of energy

That is why vegeterian diet is the best to conserve energy and to save the World although protein is also needed for human being (but not a lot of it is required).