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Energy Flow. I can construct pyramids of number and pyramids of biomass I can explain efficiency of energy transfer and can use this to explain food chain limitations I can calculate efficiency of energy transfer. Food Chains. Primary Consumer. Secondary Consumer. Tertiary Consumer.
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I can construct pyramids of number and pyramids of biomass • I can explain efficiency of energy transfer and can use this to explain food chain limitations • I can calculate efficiency of energy transfer
Food Chains Primary Consumer Secondary Consumer Tertiary Consumer Producer
Where does the energy in a food chain come from? • Why do we call plants producers? • What do the terms herbivore, omnivore and carnivore mean?
Pyramid of Numbers e.g. 1000 clover > eaten by 100 snail > eaten by 10 thrush > eaten by 1 hawk
Pyramids of numbers are not always pyramid shaped: 10s of foxes 100s of shrews 1000’s of caterpillars 1 oak tree
At each stage of the food chain energy is lost as heat etc, and used for growth.
Fox 1Kg Fox 90% of the energy is lost from the second consumer Energy is lost by movement, heat etc. Grass 100Kg Grass Only 1-5 % of the suns energy is used in photosynthesis. Energy is lost in evaporation etc. Rabbit 10Kg Rabbit 90% of the energy is lost from the first consumer Energy is lost by movement, heat etc.
Draw your own food chain and identify the producer, the primary consumer and the secondary consumer. • Now draw your food chain as a pyramid of numbers • Now draw it as a pyramid of biomass.
Energy supplied (input) Efficiency = Energy used for growth (output) The above equation allows us to calculate the efficiency of energy transfer. Every trophic level can lose up to 90% of its available energy, this means that food chains are limited in length.
INPUT OUTPUT 3056 KJ of energy in the grass 125 KJ for Growth 1909 KJ in waste 1022 KJ in heat loss Answer: 0.04 or 4%
Why do vegetarians have better energy efficiency? • Why do food chains have a limited number of links?
Can construct pyramids of number and pyramids of biomass • Can explain efficiency of energy transfer and can use this to explain food chain limitations • Can calculate efficiency of energy transfer