Biology 3 Unit 4

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Biology 3 Unit 4
2013-05-11 14:20:01

How humans affect the environment
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  1. How do human pollute water?
    • Humans pollute water with:
    • Sewage
    • Fertiliser
    • Toxic chemicals
    • Causing high level of nitrates in the water
  2. How do humans pollute the air?
    • Humans pollute the air with:
    • Smoke and gasses such as sulphur dioxide, which contributes to acid rain
  3. How do humans pollute land?
    • Humans pollute land with:
    • Toxic chemicals such as pesticides and herbicides, which may be washed away into the water
  4. What is the effect of large scale deforestation?
    • Deforestation has:
    • Increased the release of carbon dioxide into the atmosphere
    • Reduces the rate at which carbon dioxide is removed from the atmosphere, by photosynthesis
    • Reduces biodiversity due to loss of food and habitat
  5. Why has deforestation occurred?
    • Deforestation has occurred so that:
    • Crops can be grown to produce ethanol-based biofuels
    • There can be an increase in cattle and rice fields to provide more food
  6. What is the disadvantage of the increase production of cattle and rice fields?
    Cattle and rice growing produce methane, which has led to an increase of methane in the atmosphere
  7. Why is the destruction of peat bogs bad?
    The destruction of peat bogs and other area of peat result in the release of carbon dioxide into the atmosphere; due to the decay of the compost by micro organisms
  8. How is carbon dioxide sequestered?
    Carbon dioxide is sequestered as carbon dioxide is removed from the air by plants and by dissolving in oceans, rivers and lakes
  9. What is meant by greenhouse gasses?
    This is the level of carbon dioxide and methane increasing in the atmosphere
  10. What will happen if there is a slight increase in the earths temperature?
    • An increase in the earths temperature may:
    • Cause big changes in the earths climate
    • Cause rise in sea levels
    • Reduce biodiversity
    • Cause change in migration patterns eg. Birds
    • Changes in the distribution of species
  11. Describe the process of ethanol-based fuels?
    • Ethanol-based fuels can be produced by fermentation
    • Glucose is produced from maize starch by the action of carbohydrase
    • Microorganisms (yeast) respire anaerobically to produce the ethanol, using sugars from crops as the energy
    • Ethanol is extracted by distillation
  12. How can the efficiency of food production be improved?
    The efficiency of food production can be improved by reducing the number of stages in food chains
  13. How can we produce meat more efficiently?
    • We can produce meat more efficiently by:
    • Preventing the animals from moving so energy isn't wasted on movement
    • Controlling the temperature of their surroundings so that energy from food isn't wasted to maintain body temperature
  14. What is meant by sustainable food production?
    This is a method of producing food which can be sustained over time without destroying the fertility of the land or ocean
  15. How are fish stocks in the ocean monitored?
    • Fishermen can only remove a strict allocation of fish per year
    • Fishermen must use certain sized nets to avoid catching small, young fish.
  16. What is mycoprotein?
    Protein from fungus
  17. What is Fusarium?
    • Fusarium is grown to produce mycoprotein.
    • This is a protein-rich food suitable for vegetarians
  18. How is Fusarium grown?
    The fungus is grown aerobically on cheap sugar syrup and the biomass is harvested and purified
  19. What factors must be controlled in large industrial fermenters?
    • pH levels
    • Oxygen levels
    • Temperature