-
(5 BYA) Forming the Solar System
About 5 BYA our sytem was a swirling mass of gas and dust.The Earth was not yet formed. -
(4.6 BYA) The Forming of the Earth
The Earth began to form and grow. This happened by coliding with space debris. -
(4 BYA)
At this point the Surface of the Earth began to cool. -
(4 BYA) Molecules
scientists say the organic molecules began to assemble. -
(3.5 BYA) Fossils
Fossils of stromatalites. Stromatalites are layered structures. Also are the oldest known fossils to man. This type of fossil is said to be the most intriging fossil. -
(3 BYA) Life
some forms of life had become photosynthetic. There was chemical traces of photosynthetic activity happening. -
(2.2 BYA)
This is when Earth probably would have looked as much as it does today. -
(2 BYA) Oxygen
O2 levels reached today's level -
(2 BYA - 1.5 BYA)
a type of aerobic prokaryote was engulfed and began to live + reproduce inside of a larger, anaerobic prokaryote. This theroy is called endosymbiosis -
(1 BYA)
Ozone (03) formed- protected organisms from harmful UV rays so they could exist on land -
(1600- 1700) Redi
Redi- a scientist that observed flies and conducted a experiment to test his hypothesis by using meat in a jar, one with a net covering the top, and the other completely open. He conducted this test to see is flies were generated spontaneously from rotting meat. -
(1700-1800) Spallanzani
Spallanzani- designed an experiment to test the hypothesis of spontaneous generation. In his conclusion he said that microorganisms are formed not from air but by other microorganisms. -
(1800-1900) Flasks and the atmosphere
Pasteurs made a curved neck on a flask. This prevented solid particles from entering the body of the flask. His experiment helped to clear up those people who still believed in spontaneous generation.
Oparin and Haldane thought that early atmosphere contained ammonia. Miller and harold tested Oparin's hypothesis by setting up an experiment -
(1900- Present Time) Cells
Fox- researched physical structures that may have given rise to the 1st cells.
Thomas Cech- found a type of RNA in some unicellular eukaryotes that are able to act as a chemical catalyst.
Margulis- proposed that early prokaryotic cells may haev developed a mutually beneficial relationship. Relized that at high temperatures these gases could form simple organic compounds similar to amino acids.
