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 is transferred 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.. This is then transferred to the locusts when they eat the plant. Therefore, biomass is transferred from the maize to the locusts. Some of the biomass in the locust is then transferred to the lizards when the lizard eats the locusts and so on.
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Loss of biomass
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 organisms in the trophic level to complete The key reactions that all living organisms complete..
Biomass can be lost between stages because of:
- excretion - water and A nitrogenous waste product resulting from the breakdown of proteins. It is excreted in urine. are excreted in urine
- respiration - carbon dioxide and water are waste products of 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., which is carried out by organisms to keep warm and provide energy for the organism
- egestion - undigested food passes through the organism and is egested as solid Waste matter from the bowels.
Because only around ten per cent of the biomass at each trophic level is passed to the next, the total amount of biomass transferred becomes very small after only a few trophic levels. Food chains are therefore 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.
