2. Formation of the Atmosphere: Asteroids and Meteorites Probably contained water and then this vaporized when it impacted forming a hazy type of atmosphere.

3. Formation of Atmosphere: Volcanic gases Volcanoes gases such as CO2, water vapor, etc. This process is called OUTGASSING

4. Formation of Atmosphere: Cyanobacteria = Photosynthetic bacteria. Pull CO2 out of atmosphere and replace it with oxygen. During Achean (Began to combine to form stromatolites during Proterozoic)

5. Evidence of Oxygen: Evidence in ROCKS Iron in Archean Rocks oxidized (rust) with the new O 2 in the “atmosphere” Left these rusted bands in the rocks

6. Formation of atmosphere: Evidence … Current atmosphere contains ozone (O3) which prevents UV from killing life on earth. Since life began to thrive, Oxygen must have been present.

7. Formation of Oceans Water vapor dropped from the atmosphere. Dissolved minerals on the surface of the land which accumulated in oceans making them salty.