Transfer of biomass
The arrows in a A sequence (usually shown as a diagram) of feeding relationships between organisms, showing which organisms eat what and the movement of energy through trophic levels. show the transfer of The dry mass of an organism. from one organism to another. An example of a food chain is:
maize → locust → lizard → snake
Some of the energy from the Sun absorbed by maize when it A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic. is transferred to the locusts when they eat the plant. So biomass is transferred. Then some of the biomass in the locust is transferred to the lizards when they are eaten and so on.
Image caption, Energy transfer
A pyramid of biomass
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Not all of the biomass is passed from the maize plants to the locusts. In fact, only about ten per cent of the biomass is transferred from each The position of an organism in a food chain, food web or pyramid. to the next. The remaining 90 per cent is used by the trophic level to complete The key reactions that all living organisms complete.. Biomass can be lost between stages because not all of the matter eaten by an organism is digested. Some of it is excreted as waste such as solid Waste matter from the bowels., carbon dioxide and water in The chemical change that takes place inside living cells, which uses glucose and oxygen to release the energy that organisms need to live. Carbon dioxide is a by-product of respiration. and water and A nitrogenous waste product resulting from the breakdown of proteins. It is excreted in urine. in urine.
Because only around 10% of the biomass at each trophic level is passed to the next, the total amount becomes very small after only a few levels. So food chains are rarely longer than six trophic levels.
In fact, only about one percent of the energy from the Sun that reaches the plant's leaves is used by the plant during photosynthesis. This sounds small but is still enough to power almost all food chains on our planet.