Powerpoint environment

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Sources: Jones, IGCSE Biology- Mackean, IGCSE Biology - Pickering, Complete Biology

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Powerpoint environment

  1. 1. Relationships of organismswithoneanother and withtheirenvironment<br />
  2. 2.
  3. 3. NUTRIENT CYCLES<br />Carboncycle<br />Watercycle<br />Nitrogencycle<br />
  4. 4. CARBON CYCLE<br />
  5. 5.
  6. 6. CARBON CYCLE<br /> REMOVAL OF CO₂ FROM THE ATMOSPHERE<br />PHOTOSYNTHESIS: uses light energytoconvert CO₂ intoorganiccompounds in plants.<br />ADDITION OF CO₂ TO THE ATMOSPHERE<br />RESPIRATION: convertscarbohydratestoCO₂ withtherelease of energy.<br />DEATH AND DECAY: provideplant and animal material fordecomposers – bacteria and fungi.<br />COMBUSTION: releasesCO₂ bytheburning of fossilfuels.<br />FOSSILISATION:Thehydrocarbonfuels, such as coal and petroleum, come fromancientplantswhichhaveonlypartlydecomposedoverthemillion of yearssincetheywereburied.<br />
  7. 7. WATER CYCLE<br />
  8. 8.
  9. 9. NITROGEN CYCLE<br />
  10. 10.
  11. 11. NITROGEN CYCLE<br />1)PROCESSES WHICH ADD NITRATES TO SOIL<br />Nitrifying bacteria: they use ammoniafronexcretoryproducts and decayingorganisms as a source of energy. In thisprocessthey produce nitrates. <br />Thereis a specialgroup, thenitrogen-fixing bacteria, which can absorb N₂ as a gas fromthe air spaces in thesoil, and builditintocompounds of ammonia, which can beeasilybechangedtonitratesbyothernitrifying bacteria. Some of theselive in therootsnodulesofleguminousplants(peas,beans, clover).<br />
  12. 12. 1)PROCESSES WHICH ADD NITRATES TO SOIL(cont)<br />Lightning: lightningdischargesmakessome of thenitrogen gas in the air combine withoxygen, formingnitrogen oxides. Theydissolve in rain, and are washedintothesoil, wheretheyformnitrates.<br />
  13. 13. 2)PROCESSES WHICH REMONVE NITRATES FROM THE SOIL<br />Uptakebyplants: plantrootsabsorbnitratesfromthesoil and combine themwiththecarbohydratestomakeproteins.<br />Leaching: as rain waterpassesthroughthesoilitdissolvesthenitrates and carriesthemaway in therun-off ortodeeperlayers of thesoil.<br />Denitrifying bacteria: Theyobtainenergybybreakingdownnitratestonitrogen gas whichthen escapes fromthesoilintotheatmosphere.<br />
  14. 14. POPULATION SIZE<br />POPULATION: group of organisms of onespecies, living in thesamearea at thesame time.<br />
  15. 15.
  16. 16. HUMAN POPULATION GROWTH<br />
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  18. 18. HUMAN INFLUENCES ON THE ECOSYSTEM<br />AGRICULTURE<br />POLLUTION<br />CONSERVATION<br />
  19. 19.
  20. 20. POLLUTION<br />WATER POLLUTION bysewage and chemicalwaste.<br />AIR POLLUTION by: - sulfurdioxide.<br /> - greenhouse gases <br />POLLUTION DUE TO PESTICIDES AND HERBICIDES.<br />POLLUTION DUE TO NUCLEAR FALL-OUT<br />
  21. 21. POLLUTION OF WATER: the 2 pollutantsthat reduce oxygen in water are:<br />Fertilisers: nitrates and phosphates are addedtothesoilbyfarmers. Some are washedfromthesoilby rain intothenearestpond, lakeorriver. Thisprocessiscalledleaching.<br />Sewage: containsanexcellentsource of organicfoodfrom bacteria, and alsocontainsphosphatesfromdetergents.<br />
  22. 22.
  23. 23. AIR POLLUTION<br />BY SULFUR DIOXIDE: contributestoacid rain.<br />BY GREENHOUSE GASES CONTIBUTING TO GLOBAL WARMING.<br />Carbon + O₂ -> carbonmonoxide (CO)<br /> and carbondioxide (CO₂)<br />Sulphur + O₂ -> sulphurdioxide (SO₂)<br />Nitrogen + O₂ -> nitrogenmonoxide (NO) <br /> and nitrogendioxide (NO₂) <br />
  24. 24. Greenhouseeffect:gasescontributing<br />
  25. 25.
  26. 26.
  27. 27.
  28. 28.
  29. 29.
  30. 30. Pollutiondueto nuclear fall-out<br />IONISING RADIATION MAY CAUSE CANCER<br />Accidents at nuclear powerstationsmayreleasesubstancesintotheatmosphere. Exposuretolargeamounts of radiationfromthesesubstances can cause radiationsickness and burns. They can alsoincreasemutationrates in DNA in ourcells, whichmay lead tocancer.<br /><ul><li>Alphaparticles
  31. 31. Beta particles
  32. 32. Gamma rays</li></li></ul><li>AGRICULTURE<br />DEFORESTATION<br />FERTILISERS<br />

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