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e) Describe how energy is transferred through ecosystems.
A food chain shows how energy is transferred from one living organism to another.
Joining food chains together to create a food web can show how energy flows through the
The level at which an organism feeds is called its trophic level.
f) Outline how energy transfers between trophic levels can measured.
Can be measured by estimating the population sizes of the organisms involved.
A value for the energy content of each organism is calculated by drying to constant mass
and then heating in a calorimeter.
The energy content times the number of organisms gives a value for the energy content of
g) Discuss the efficiency of energy transfers between trophic levels.
At each trophic level, some energy is lost, and therefore unavailable at the next trophic
Life processes, such as respiration, release energy, some of which is converted into heat
Energy remains stored in dead organisms and waste material, which is then only
available to decomposers. This waste material includes parts of animals and plants that
cannot be digested by consumers.
Because of this, there is less energy available to sustain living tissue at higher levels of the
food chain, and so less living tissue can be kept alive.
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Explain how human activities can manipulate the flow of energy through ecosystems.
Productivity: the rate at which plants convert light energy into chemical potential energy.
Gross Primary Productivity: the total quantity of energy transferred by plants from sunlight into
Net Primary Productivity: the energy that is left as chemical energy after the plants have
supplied their own needs by respiration.
Improving primary productivity:
Light intensity can limit photosynthesis and NPP.
Provide a longer growing season to harvest more light.…read more
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Antibiotics prevents energy losses to pathogens and parasites.
Zero grazing animals waste energy walking around and keeping body temperature stable;
by reducing movement, supplying food to them and keeping the environmental temperature
constant, more energy can be allocated to muscle production.…read more