early atm pt 2
Storyboard Text
- After billions of years of Stromatolites producing O2, it had fully oxidized everything it could bond with and there was nowhere for it to go but the atmosphere. It happened pretty quickly, about 2.2 years ago our atmosphere was about 20% O2. This process killed many of the early organisms as they weren't adapt to breathe O2. This also led to the production of the ozone layer which prevents the suns UV rays from reaching the Earths surface.
- Since then levels of multiple gases changed a lot. Around 500 million years ago the atmosphere consisted of about 7%. This was wonderful for the evolution of plants fast forward to 300 million years ago CO2 levels remained at about where they are now. During that time O2 levels rose to about 35%.
- Now Earth"s atmosphere is now made up of 78% nitrogen, 21% oxygen, and 1% argon, methane, ozone, water, and carbon dioxide but they are still changing. These levels are changing because people are constantly burning oil and coal releasing carbon dioxide into the air. This has caused our CO2 levels to be the highest its ever been in 650,00 years.
- Ar. CH4, O3, H2O, and CO2
- O2
- N
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