Early Atmosphere

Early Atmosphere

1. 1) VOLCANOES _The Earth is molten, any atmosphere is boiled away.

   • 1a) things start to cool and so a thin layer of crust is formed, volcanoes erupt .
     • 1b) volcanoes give out Carbon dioxide and water vapour.
       • 1c) oceans formed when water vapour condensed
   • Early atmosphere= mostly carbon dioxide/ virtually no oxygen

2. 2) GREEN PLANTS_ a lot of early carbon dioxide dissolved into the oceans.

   • 2a) when marine animals developed they took in the carbon dioxide, when they died they were buried under layers of sediment.
     • The carbon dioxide became locked up in carbonate rocks.
     • 2b) Green plants developed, they removed the carbon dioxide from the air and produced oxygen.
       • The oxygen levels gradually increased.

3. 3) OZONE LAYER_ The build up of oxygen caused some organisms to die and others to flourish.

   • 3a) The ozone layer (created by the oxygen) blocked harmful rays from the sun- allowing more organisms to develop.
     • very little (0.04%)carbon dioxide is left now.

4. TODAYS ATMOSPHERE : Nitrogen-78% oxygen 21% argon and other gasses 1% carbon dioxide - 0.04%