Where Did Earth's Atmosphere Come From?

Question

I am doing this for science homework due tommorow so answer fast.

Answer 1

Plant life. For most of the earth's history it had an atmosphere composed of other gasses.

Algae in the seas started pumping oxygen into it in the Precambrian.

Answer 2

The short version.... The earth was forming by meteors impacting the surface. These impacts released dust into the sky. The clouds becomes storms...... the lightning strikes created amino acids (actually experimentally proven)... amino acids became single celled eukaryote cells, and the process of evolution continued.

Now the oxygenation of the earths atmosphere is another story. As evolution continued we find this slimy organic mat... the mats are an algae called stromatolites. These stromatolites were photosynthetic, putting oxygen into the earths atmosphere. We see evidence in these rock formations called the Banded iron formation. The BIF shows layers of chirt and hematite, which is an iron oxide. because of the hematite when can see that the atmosphere was oxygenated.

Answer 3

Impacts of comets during early Earth history. Lots and lots of dirty snowballs. These also carried the building blocks for life onto the planet -amino-acids, etc.

Answer 4

Alot of the atmoshere came from volcanoes, then plant life converted the CO2 to oxygen

Answer 5

About
Please go through these sites and google search results.. There is a powerpoint presentation also...

http://en.wikipedia.org/wiki/Atmosphere
http://www.ux1.eiu.edu/~cfjps/1400/atmos_origin.html
http://des.memphis.edu/lurbano/Geog1010/Fall04/Origin_atmosphere.ppt

Google results:
http://www.google.co.in/search?q=Origin+of+Atmosphere