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(5BYA) Solar System
Big swirling mass of gas began to form into the solar system -
(4.6 BYA) Earth
The Earth began to form and grew by colliding with space debris -
(4BYA) Atmosphere
Volcanoes emit gas forming an atmosphere -
(3.5BYA) Fossils
Fossils of stromatolites were as old as 3.5 billion years -
(3BYA) Cyanobacteria and lynbgya
Cyanobacteria and lynbgya had began to photosynthesise -
(2.2 BYA) Earth
Earth looks mostly like what it is today -
(2BYA) Oxygen
O2 levels reached todays levels -
(2BYA-1.5BYA) Prokaryotic life forms
A type of small aerobic prokaryotic life forms was engulfed by and began to live and reproduce inside of a larger anaerobic prokaryote -
(1BYA) Ozone
Ozone (O3) formed - protected from harmful UV rays so they could exsist on land -
(1665) Microscopes
An early light microscope was used by Robert Hooke to study nature. Other scientists observed from microscopes that mircoorganisms are simple in structure and are numerous and wide spread. -
(1668) Redi's experiment
Discovered that flies only come from eggs laid by other flies. -
(1700s) Spallanzani's experiment
Discovered that boiled broth became contaminated only when microoganisms from the air entered the flask. -
(mid-1800s) Pasteur's experiment
Discovered that contamination of the broth was due to microorganisms in the air. -
(1920s) Oparin's hypothesis
Thought the early atmosphere contained ammonia, NH3 (hydrogen gas), H2 ( water vapor), H2O, and compounds made of hydrogen and carbon. Oparin thought at high temperatures these gases might have formed simple organic compounds. -
(1950) Radiometric dating
Used to establish ages of materials like fossils. -
(1953) Urey and Miller
Used Opain's hypothesis to produce a variety of organic compunds and amino acids. -
(mid-1950s) Sidney Fox
Extensive research on the physical structures that meny have given rise to the first cells (microshperes and coacervates). -
(early 1980s) Thomas Cech
Found that a type of RNA found in some unicellular eukaryotes is able to act as a chemical catalyst. -
(1980s) Lynn Margulis
Proposed that early prokaryotic cells may have developed a mutually beneficial relationship.
