Biomass - mass of living material in plants and animals
Pyramid of biomass - represents mass of organisms, and can be more accurate than a pyramid of numbers - many insects may feed on one bush, but the bushes mass is more than all the insects masses
Green plants transfer solar (light) energy to a chemical energy which is passed through the food chain
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B1.5.2 - Energy Transfers
Energy is wasted in the food chain, so not all the energy taken in is used for growth
Not all food can be digested, so is stored in faeces and urea (waste materials)
Some biomass is used for respiration, releasing energy in the process, which includes movement so if something moves a lot, it uses less energy to grow
Animals need to keep at a constant temperature, so some energy is used for this
Much of the energy released in respiration is eventually transferred to the surroundings
Sankey diagrams are used to represent the energy intake and use or transfer in animals
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B1.5.3 - Decay Processes
All organisms take up nutrients, which they eventually release, as they would otherwise run out
Detritus feeders start the decay process, by eating dead organisms and producing waste material, then decay organisms break down the waste or the dead organism
Decay organisms are microorganisms called decomposers
Decay is faster if it's warm and wet and many decomposers also need oxygen
All of the materials from the waste and dead organisms is recycled, returning nutrients to the soil
Sewage treatment plants and composts heaps are used by humans to recycle waste
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B1.5.4 - The Carbon Cycle
Recycling carbon involves photosynthesis and respiration
Photosynethesis takes CO2 from the atmosphere
Animals and green plants respire, returning CO2 to the atmosphere
When trees are cut down and burnt, CO2 is released back to the atmosphere
Animals eat green plants, which builds up carbon in their bodies, and when they die or produce waste, microorganisms release CO2 back into the atmosphere through respiration
A stable community recycles all the nutrients it takes up
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B1.5.5 - Recycling Organic Waste
Waste vegetables, peelings, grass cuttings and clippings from trees contain organic waste that can be recycled
It can be composted in many ways, the most efficient allow the waste to mix with oxygen and moisture, letting energy escape by heating surroundings - adding worms and layers of garden soil can speed the process up
Councils also collect garden waste, using shredders and large bins to compost material
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