Early Atmosphere

1) VOLCANOES _The Earth is molten, any atmosphere is boiled away.
1. 1a) things start to cool and so a thin layer of crust is formed, volcanoes erupt .
  1. 1b) volcanoes give out Carbon dioxide and water vapour.
    1. 1c) oceans formed when water vapour condensed
2. Early atmosphere= mostly carbon dioxide/ virtually no oxygen
2) GREEN PLANTS_ a lot of early carbon dioxide dissolved into the oceans.
1. 2a) when marine animals developed they took in the carbon dioxide, when they died they were buried under layers of sediment.
  1. The carbon dioxide became locked up in carbonate rocks.
  2. 2b) Green plants developed, they removed the carbon dioxide from the air and produced oxygen.
    1. The oxygen levels gradually increased.
3) OZONE LAYER_ The build up of oxygen caused some organisms to die and others to flourish.
1. 3a) The ozone layer (created by the oxygen) blocked harmful rays from the sun- allowing more organisms to develop.
  1. very little (0.04%)carbon dioxide is left now.
TODAYS ATMOSPHERE : Nitrogen-78% oxygen 21% argon and other gasses 1% carbon dioxide - 0.04%

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	Erstellt von greenchloe1998 vor mehr als 9 Jahre