1. Evolution of the atmosphere
Earth Science II
(Session 5)

2. European Southern Observatory (1999)
The solar nebulous from which the Sun and the planets were formed 5 thousand years ago was mostly hydrogen and helium.

3. Therefore:
Scientists hypothsize 4.5 billion of years ago, the atmosphere was formed by hydrogen and helium.
This started a slow and extraordinary process of formation of the actual atmosphere.

4. When the Earth was formed approximately 4
When the Earth was formed approximately 4.5 billion years agos the atmsophere started to undergo changes:
H2 , He, dust
Other gases
heat
lightening
N2 . CO2 , CH4 , NH3 , H2O
Primitive atmosphere
gravity
LUV
lightening
Larger organic molecules
Small organic molecules
organization
LUV
evolution
Organisms that
degrade carbon dioxide
Primitive cell
Radiation
H2O vapor
Oxygen (O2)

5. Actual atmosphere
Actual atmosphere is very diffrerent from when the beginning of Earth.
Now it is mostly composed by nitrogen and oxygen.

6. Composition of primitive atmosphere vs. Actual atmosphere
Gas
Primitive
Actual
Carbon dioxide
92.2%
0.03%
Nitrogen
5.1%
78.0%
Sulpher dioxide
2.3%
Traces
Hydrogen Sulfide
0.2%
Ammonia
0.1%
Methane
Oxygen
0.0%
21.0%
Argon
0.9%
DiSpezio, Michael , et al. (1999)

7. Production of life in the laboratory
Sidney W. Fox et. al. From the Molecular evolution Institution in Miami have informed in recent years about a series of experiments about synthesizing life in a test tube: They wanted to grow live proteins fabricadted under similar conditions of the primitive earth
A = indicate the proteinoide highly similar to a baceria seen from an electronic microscope.
B = indicates formations in the proteinoide similar to a bacteria or yeast when it is asexually reproducing by the process known as gemation.

8. Class reading From your textbook…
Science and Society: Solutions to air pollution
Page 410

9. Bibliography
DiSpezio, M. et al. (1999). Science Insights: Exploring Earth and Space. 1era ed. Estados Unidos de América: Prentice Hall.
European Southern Obsevatory (1999). A powerful twin arrives [Imagen]. European Southern Obsevatory. Extraído el 1 de abril de 2003 de la World Wide Web: :