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Biology Revision notes:
Energy and Nutrient Transfer in Food Chains
This is an example of a pyramid of numbers; the width of the bar represents the number of
organisms included in the food chain, the bar representing the oak tree is small as it has a higher mass
than an insect or woodpecker.
However, as the insects eat more tree than they weigh, this can be misleading. A clearer pyramid is
the pyramid of biomass, as the width of each bar represents the mass of each organism in the food
chain, so it doesn't matter how big each individual organism is.
The arrow in a food web means `eaten by' it is the direction the
energy/ nutrients are travelling
At each stage in the food chain, energy is lost through;
Faeces and urine
Cell repair and maintenance
Energy is not lost through growth, but used.
Energy from the sun is the energy source for all organisms-
producers respire to make food, and consumers eat producers.
Producers (plants) only capture a small amount of the energy that reaches them
To work out the percentage energy transfer, divide the final energy by the first energy and
E.g. 50/97000 x 10= 0.05 %