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The Earth’s Atmosphere. Visit www.worldofteaching.com For 100’s of free powerpoints. Volcanic activity. 4 billion years ago. Water vapour condenses to form oceans. Mainly carbon dioxide. Some methane, ammonia and water vapour. Plants evolve. 3 billion years ago.
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The Earth’s Atmosphere Visit www.worldofteaching.com For 100’s of free powerpoints
Volcanic activity 4 billion years ago Water vapour condenses to form oceans Mainly carbon dioxide Some methane, ammonia and water vapour Plants evolve 3 billion years ago Plants give out oxygen – atmosphere polluted by oxygen Carbon & carbon dioxide taken in by sedimentary rocks as carbonates and fossil fuels Methane & ammonia react with oxygen – some nitrogen produced Nitrogen produced by organisms including denitrifying bacteria Micro-organisms that cannot tolerate oxygen killed off 2 billion years ago Oxygen results in ozone layer Ozone layer filters out harmful ultra violet light This allows evolution of new organisms 1 billion years ago Atmosphere for the past 200 million years: 80% Nitrogen 20% Oxygen Now Small amounts of other gases including water vapour, carbon dioxide, noble gases