C1 Topic 1- The sea and atmosphere Flashcards
What is the atmosphere made up of?
78% nitrogen
21% oxygen
1% argon
0.04% carbon dioxide
What made up the early atmosphere?
Mostly carbon dioxide with virtually no oxygen.
How were the oceans formed?
The volcanos gave out lots of gases such as carbon dioxide and water vapour. When the water vapour condensed it formed the oceans.
How did oxygen levels increase and carbon dioxide levels decrease?
A lot of carbon dioxide dissolved in the oceans when they were formed. An increase in green plants decreased carbon dioxide levels and increased oxygen levels due to photosynthesis.
How was the ozone layer formed what did it do?
The ozone layer formed from the oxygen increase. This blocked harmful rays from the sun and enabled more complex organisms to evolve.