Earth's atmosphere

By: Alec McCoy, Thomas Johnson, Jacob Garcia

The first atmosphere…

After loss of the hydrogen, helium and other hydrogen-containing gases from early Earth due to the Sun's radiation the earth was devoid of an atmosphere for many years. The first atmosphere was created by the outgassing of the gases trapped in the interior of earth.

Oxygen introduction...

The evolvement of photosynthetic organisms played a large roll in the introduction of oxygen into the atmosphere. Blue Algae began to feed off of the carbon dioxide in the atmosphere, this process produced free oxygen though this oxygen did not build up in the atmosphere due to it being taken up by rocks. It was not until about 1 billion years ago the the reservoirs of oxidizable rock became saturated and the free oxygen stayed in the air. Once oxygen had been produced, ultraviolet light split the molecules, producing the ozone UV shield as a by product.

Overview...

First: Early atmosphere is dominated by water vapor and carbon dioxide.


Second: Photosynthesis begins production of and introduction of free oxygen into the atmosphere.


Third: The availability of oxygen enabled the diversification of metabolic pathways, leading to a great increase of life which increased oxygen production.