How are food pyramids different to food chains? A food pyramid is another method of showing how food is consumed within an ecosystem. The difference between a food pyramid and a food chain is that a pyramid shows the transfer of matter within an ecosystem rather than energy. It uses biomass, the weight of all organisms at a particular trophic level in a given environment. 3rd order 2nd order consumer 1st order consumer Producer As the trophic levels increase the biomass decreases. There are always less carnivores at the top of a food chain or pyramid than herbivores or plants. One large fish needs 100 times its body weight to gain enough energy to survive: 2kg larger fish 200kg small fish 600kg zooplankton 1000kg phytoplankton There is a reduction in this biomass because: Not everything in the lower level of the pyramid gets eaten Not everything that is eaten is digested Energy is always lost as heat As a generalisation each level on a food pyramid will have a biomass 10% of the biomass of the level below it as only 10% of energy is passed on as the animal is eaten.

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