Decay - B4 GCSE OCR
- Created by: bjoejhprethyre2
- Created on: 20-11-16 12:30
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- DECAY
- Micro-organsims
- decomposing is done by micro-organisms
- Decomposers: Soil Bacteria Fungi
- 2 types in decay: Detritivores and Saprophytes
- Detritivores feed on dead or decaying material
- Examples: earthworms, maggots and woodlice
- They break up material into smaller parts and which gives them a bigger SA to work on which speeds up decay
- Examples: earthworms, maggots and woodlice
- Saprophytes feed on decaying material through extracellular digestion
- Example: fungi
- they feed by secreting digestive enzymes which break down the material into smaller bits which are then absorbed by the saprophytes
- Example: fungi
- Detritivores feed on dead or decaying material
- decomposing is done by micro-organisms
- Rate of Decay
- Affected by 3 main factors:
- Temperature
- Moister things decay faster
- micro-organisms need water
- Moister things decay faster
- Water
- Warmer temperature makes things decay faster
- speeds up respiration in micro-organisms
- Warmer temperature makes things decay faster
- Oxygen
- More oxygen makes things decay faster
- Micro-organisms respire aeorbically when there is more oxygen so they will provide more energy to the decaying process
- More oxygen makes things decay faster
- Optimum levels of these 3 factors means there will be more micro-organisms which will make the object decay faster
- Temperature
- Affected by 3 main factors:
- Reducing Rate of Decay
- Canning
- Keeps decomposers out
- Cooling
- Slows down decomposers reproduction rate
- Freezing
- Stops decomposers reproduction
- Drying
- Not enough water for decomposers to carry put cell reactions
- Adding salt or sugar
- High concentrations of salt or sugar cause the decomposers to dry out because of osmosis. so they can't work
- Adding vinegar
- The acidity of the vinegar kills the decomposers
- Canning
- Micro-organsims
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