Evolution of the atmosphere Earth Science II Session

Evolution of the atmosphere Earth Science II (Session 5)

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.

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.

When the Earth was formed approximately 4. 5 billion years agos the atmsophere started to undergo changes: H 2 , He, dust Other gases heat N 2. CO 2 , CH 4 , NH 3 , H 2 O lightening Primitive atmosphere gravity Small organic molecules lightening LUV evolution Primitive cell H 2 O vapor Radiation LUV Larger organic molecules Organisms that degrade carbon dioxide Oxygen (O 2) organization

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

Di. Spezio, Michael , et al. (1999) 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% Traces Ammonia 0. 1% Traces Methane 0. 1% Traces Oxygen 0. 0% 21. 0% Argon 0. 0% 0. 9%

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.

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

Bibliography • Di. Spezio, M. et al. (1999). Science Insights: Exploring Earth and Space. 1 era 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: : http: //www. eso. org/outreach/press-rel/pr 1999/phot-40 b-99 -preview. jpg