Life caused change

• As life developed, it started to change the environmental conditions of earth which made it possible for new life and new habitats.
• Atmospheric oxygen

  • Archaea in the oceans developed the ability to photosynthesise and release oxygen.
  • For years, all the oxygen produced reacted with iron in the oceans.
  • Once all the iron had reacted with oxygen, the rest of the dissolved oxygen built upon the oceans.
  • this was released into the atmosphere where concentrations started to rise.
  • oxygen absorbed UV light, producing a dynamic equilibrium of reactions involving o3, o2, and o.
  • absorption of UV light made life on earths surface possible.
• carbon sequestration

  • co2 helps to retain heat energy in the atmosphere.
  • Photosynthetic organisms absorbed carbon dioxide, which was stored in geological sediments such as carbonate rocks and fossil fuels.
  • this reduction in atmospheric co2 levels helped to prevent a long-term temp rise.
• transpiration

  • returned water vapour to the atmosphere and increased the amount of rainfall in other areas, making growth of even more plant life possible.