the evolution of the atmosphere

• phase 1 - volcanoes gave out gases such as nitrogen which built up the atmosphere
• phase 2 - the water vapour condensed and formed the oceans. oceans, algae and green plants absorbed carbon dioxide from the atmosphere
• some of the carbon that the organisms took in from the atmosphere becomes trapped in rocks and fossil fuels after they have died
• phase 3 - green plants and algae produced oxygen through photosynthesis