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5 BYA, The very beginning
The solar system began to form. It was a swirling mass of gas and dust, -
4.6 BYA, collisions starting to form earth
The earth started to form. It started to grow by coliding with space debris. -
4 BYA, earth continues to form
The earth grew larger pulling in debris with gravity. Organic molecules began to accumulate creating some of the earths oldest rocks and crystals. -
3.5 BYA, Fossils begin to form
Fossils of stromatolites or layered structure began to form from the multiple collisions. -
3 BYA, Photosynthesis
Forms of life became photosynthetic. Chemical traces of photosynthetic activity were found. the oldest known fossils were from around this time. -
2.2 BYA , modern earth
The earth around this time looked alot like it does today from the collisions and gas around the planet -
2 BYA, O2 levels compared to todays
The O2 levels reached todays levels. -
1.5 BYA Reproduction began
A type of small aerobic prokaryote was engulfed and began to live and reproduce inside of a larger, anaerobic prokaryote. This theroy is called endosymbosis. -
1 BYA The new ozone
The ozone (O3) was formed. The ozone layer protected organisms from harmful UV rays to the could live and exist on land. -
(1600-1700), Flies help understand
The scientist Redi observed flies. He conducted an experiment to test his hypothesis about flies. He further looked into the fact that flies were generated spontoneously from rotting meat. -
(1700-1800), spallanzani's new idea's
Between these years, Spallanzani designed an experiment to test the hypothesis of spontaneous generation of microorganisms. When he was finished experimenting, he concluded that microorganisms formed NOT from air but from the reproduction of other microorganisms. -
(1800-1900), pasteurs design
Between these years, Pasteurs made a curved neck flask which was designed to prevent solid particles from entering the body of the flask such as oxygen. This experiment proved that if no oxygen could enter, then nothing can live within the flask. It cleared up the thoughts of those who still believed in the spontaneous generation. -
(1800-1900) CONTINUED, new theories
Not only did Pasteurs prove this point but Oparin and Haldane thought that the early atmosphere contained ammonia. This was a hypothesis that was thought of but he never got to test it. When Miller and Harold tested his hypothesis they set up and experiment and proved that Oprain and Haldane's hypothesis was proven. -
(1900-present), the study of the fiirst cells
Sidney Fox was doing extensicve research on the physical structures that may have given rise to the first cells. In 1947 Thomas Cech found that a type of RNA found in some unicellular eukaryotes was able to act as a chemical catalyst. In 1938 Margulis proposed that early prokaryotic cells amy have developed a mutually benefical relationship. At high temperatures these gasses may have formed simple organic compounds like amino acids.
