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biology 0610printed 267 · PDF 267
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●A pyramid of numbers shows the numbers of organisms in a habitat, starting from
the producers at the bottom to the primary consumers above them and so on until the
end of the food chain is reached.
●A pyramid of biomass(total mass of living material) does the exact same thing but
with biomass instead of numbers.
●Imagine the food chain Oak Tree → Caterpillar → Bluetit → Sparrowhawk. The
pyramid of numbers and of biomass are shown below for this food chain.
●The pyramid of numbers may not always be shaped like a regular pyramid but the
pyramid of biomass will always be since the total mass of organisms will continuously
decrease from bottom to top.
Pyramid of Energy
●A trophic level is the position of an organism in a food chain, food web or ecological
pyramid.
●The trophic levels are producer, primary consumer, secondary consumer, tertiary
consumer and quaternary consumer.