Evolution of Earth Atmosphere

• Three main gases in the atmosphere and 200 million years ago

  1. Oxygen
  2. Carbon dioxide
  3. Water vapour
• Percentage of Oxygen

  • 20 per cent
• Percentage of Carbon Dioxide

  0.03 per cent - 0.04 per cent
• Percentage of Nitrogen

  • approximately 80 per cent
• Have the proportion of gases changed since 200 million years ago?

  • No
• Small proportions of...

  • carbon dioxide
  • noble gases
  • water vapour