This gas was poisonous to the early lifeforms struggling to survive in an unforgiving world. The corrosiveness of oxygen required that organisms develop protective membranes to limit oxygen's contact with delicate tissues. Oxygen eventually accumulated in the atmosphere. All of the radiation absorbed through the splitting of oxygen and ozone molecules results in a radiation shield in the stratosphere. With ozone in place as a radiation shield, life was then able to populate the land.
Atmospheric oxygen colors our world by oxidizing minerals and scattering our sun s rays.
Oxidized compounds, like the minerals in weathered rocks, tend to be bright colors such as yellow, orange, red, purple, etc. Unoxidized compounds are often dark colors such as brown, green, black, and grey. The sky is blue because sunlight is scattered by particles in the atmosphere, many of which are oxygen molecules.