Oxygen increase and CO2 decrease

• what organisms increased the amount of oxygen in the earths atmosphere

  algae and plants
• write the balanced symbol equation for photosynthesis

  6CO2 + 6H2O -> C6H12O6 + 6O2
• when did oxygen first start appearing in the atmosphere and which organism was responsible

  2.7 billion years ago : algae
• other than photosynthesis what other factors decreased the level of carbon dioxide in the atmosphere

  formation of sedimentary rocks and fossil fuels
• describe the main changes to the atmosphere over time and the likely causes of these changes

  • intense volcanic activity- water vapour, co2, nitrogen, ammonia, methane released
  • water vapour condensed to form oceans
  • atmosphere mostly co2
  • co2 dissolved in oceans
  • photosynthesis
  • plants evolved, decrease of co2
  • co2 levels decrease during formation of sedimentary rock