The Evolution Of The Atmosphere Flashcards
What happened in phase one?
The earths surface was originally Molten so any atmosphere was boiled away
Things cooled down, crust formed and volcanoes kept erupting
Volcanoes gave out a lot of gas which is how the atmosphere and oceans were formed
What was the earths early atmosphere probably made from?
Mostly co2, virtually no oxygen
May have been small amounts of water vapour
The oceans were formed when this water vapour condensed
What happened in phase 2?
Green plants and algae evolved
A lot of Co2 dissolved into ocean, some was absorbed by plants which also produced o2 in photosynthesis
Plants and algae died and were buried under layers of sediment along with skeletons
The carbon and hydrocarbons inside them became locked up in sedimentary rock as insoluble carbonates and fossil fuels
When we burn fossil fuels today what happens?
The locked up carbon is released and the concentration of co2 in the atmosphere rises
What happened in stage 3?
The build up of oxygen in the atmosphere killed some organisms but allowed others to thrive
The oxygen also created the ozone layer which blocked harmful rags from the sun and allowed complex organisms to evolve
There is virtually no co2 left now
