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(5 BYA) Beginning of the Solar System
5 billion years ago the solar system was a swirling mass of gas and dust. -
(4.6 BYA) Formation of the Sun
Gravity pulled together the gas and dust in the solar system and formed the sun. -
(4 BYA) Formation of Planets
The remaining material in the Solar System from the sun made the planets, which cirlced the sun.
Earth colliding with the debris caused it to grow. The collisions were powerful enough to create thermal, which could have melted parts of Earth's surface.
Scientists estimated the age of the Earth by using a process called radiometric dating. They used uranium to figure out the oldest unmelted surface rock, which was about 4 billion years old. -
(3.5 BYA) Stromatolites
Stromatolites began to grow in colonies and in layers -
(3 BYA) O2
O2 began to be made because of photosynthesis. O2 got greater, it rose and sunlight broke it apart and began to make O3, which is poisonous. -
(2.2 BYA) Earth
2.2 billion years ago Earth finished developing, and remains the same way today. -
(2 BYA) O2 Levels
O2 levels increased, and reached the levels where they are today. It started to create the ozone layer at the top of our atmosphere. -
(1.5 BYA) Endosymbiosis
A small prokaryote was englufed by a larger one and they began to reproduce, making eukaryotes. -
(1 BYA) Earth's Ozone Layer
Earth's Ozone (O3) formed protecting organisms from harmful UV rays so they could exsist on land. -
(1600-1700's) Redi's Experiment
Redi did an experiment to prove that flies did not just appear from rotten meat. His experiment showed this because the meat that was exposed to flies created flies, but the meat not exposed to flies remained free of them. -
(1700-1800's) Spallanzani's Experiment
Spallanzi did an experiment to support his hypothesis that microorganisms were carried in the air, not spontaneous. He set up two flasks with broth, one sealed and one open. He then boiled the broth to kill any microorganisms, then let the flasks cool. The open flask became cloudy, but the sealed flask remained clear. -
(1800-1900's) Pasteur's Experiment
Pasteur did an improved form of Spallanzani's experiment to also show that microorganisms were in the air not spontaneous. He used a curve neck flasked with broth and boiled it. He let the cruve neck stay on the flask for a year and the broth remained clear. He then broke the neck off and the broth became cloudy. -
1900's-Urey and Miller
Oparin formulated a hypothesis that said at high temperatures the gases amonia, hydrogen, water vapor and methane formed simple organic molecules, such as amino acids. Then, the water vapor formed lakes and the organic molecules went through reactions with lightning and UV rays which made them into macromolecules. Miller and Urey then performed experiments based on Oparin's hypothesis to use reactions to create organic molecules. -
(1980's) Thomas Cech
Thomas Cech made the discovery that RNA could act as a catalyst and create chemical reactions. This lead to the discovery that RNA could cause it's own replication. -
(1700-1800's) Microscope
During this time, scientists started using the microscope, allowing them to see tiny particles. -
(1900's) Lynn Margulis
Lynn Margulis made the discovery of Endosymbiosis, the process which the first eukaryotes came from. -
(1900's) Sidney Fox
Sidney Fox has done research on the structures, including microspheres and coacervates that gave rise to the first cells. These structures form spontaneously under certain conditions. -
Radiometric Dating
Radiometric dating is a process used to determine the age of materials. It used by using the half life of radioactive ions in materials.
