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  • Created by: leena
  • Created on: 07-06-12 23:40

the impact of change

changes in the environment affect the distribution of living organisms

sometimes its difficult to determine which is affecting   the organism 

the large fall of bee population may have been caused by chemical sprays by farmers, viral disease or possibly changes in flowering patterns

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pyramids of biomass

biomass is the mass of living material in plants and animals

a pyramid of biomass represents the mass of the organisms at each stage in a food chain (more accurate than the pyramid of numbers)

green plants transfer solar energy to chemical energy which is the passes through the food chain 

biomass is the dry mass of living material in an organism

the biomass at each stage in a food chain is less than at the previous stage

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energy transfers

there is energy wastage between each stage of food chain 

not all of the food eaten can be digested,so energy is sorted in faeces or as urea in urine

some of the biomass is used for respiration which releases energy for living processes 

materials are used at each stage and energy may be transferred to the surroundings

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decay processes

all organisms take up nutrients.

if they didnt eventualy release them the nutrients would run out

detritus feeders  may start the process of decay by eating dead animas or plants and producing waste materials

decay organisms then break down the waste or dead plants and animals

bacteria and fungi are caled decomposers they decay faster if it is warm and wet

many decomposers need oxygen

humans can reyce waste in sewage treatment plants and compost heaps

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the carbon cycle

the recycling of carbon involves both photosynthesis and respiration

photosynthesis removes CO2 from the atmosphere

when humans cut down and burn trees, CO2 is released

the constant cycling of carbon in nature is known as the carbon cycle

during  photosynthesis carbon dioxide is removed from the atmosphere

the processes of respiration and combustion return carbon dioxide to the atmosphere 

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recycling organic waste

waste vegs and peeings from kitchen  contain organic waste (can be recycled)

can be composted in-several ways

efficient ways of composting allow the waste mixture with oxygen and moisture

gardeners may add worms and layers of garden soil to composters to speed up the process

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