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Biology Timeline

Essay by   •  November 6, 2010  •  399 Words (2 Pages)  •  1,562 Views

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4.5 Billion years ago

* Gas condenses: Gravity compresses the hot particles thus forming our planet.

* Our planet cools: heat and gas escape the crust through volcano's.

4.0 Billion years ago

* Rain and steam create oceans: Evaporation produces a rich soupy breeding ground

* Hydrogen, nitrogen, CO2 and other elements hang in the air and dissolve in the water where much of the action takes place.

* DNA forms and self replicates - one chain can copy the other.

3.5 Billion years ago

* Cell walls surround the replicating

3.0 Billion years ago

* Because DNA continues to replicate within the cell wall... A single compartment divides into 2 cell division.

* Some microorganisms "learn" to convert sunlight into sugar. (Photosynthesis)

* (Remember...we are still under water)

* A few microorganisms "learn" to use the waste O2 of photosynthesis...

* Cells develop modes of locomotion

3.0 - 5.0 Million years ago

* The waste of photosynthesis is oxygen. O2 escapes the ocean and begins to accumulate in the atmosphere, eventually forming the ozone. Ozone protects from solar radiation. Making the land/air habitable.

1.5 Billion years ago

* Cells begin

...

...

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