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(5BYA) A Solar System
Five billion years ago the solar system began to form. At first it was just swirling dust and gas, but it was all slowly pulled together. -
(4.6BYA) Earth is Created
The beginnings of our Earth were just starting to come together. Debris in the solar system collided, creating plantets. Earth grew larger each time it collided with debris. -
(4BYA) Organic Material
The first organic molecules began to accumulate. The oldest rocks and crystals that have been discovered date back to this time. -
(4BYA) Life on Earth
Something similar to archea was the first cellular life that appeared on Earth. -
(3.5)BYA Stromatolite Fossils
Stromatolite fossils date back this far. -
(3BYA) A New Way of Life
Life forms became photosynthetic. -
(2.2BYA) The World as We Know It
Earth appeared very similar to how it looks now. -
(2BYA) Oxygen
Oxygen levels reached those of today -
(2BYA-1.5BYA) Endosymbiosis and Mitochondria
An anaerobic prokaryote engulfed an aerobic prokaryote which began living and reproducing inside of it. This evelved into mitochondria. -
(1BYA) The Ozone
The Ozone formed, protecting organisms from UV rays and allowing life forms to live on land -
(1600-1700) Meat and Flies
Redi thought meat kept away from adult flies would not have maggots on it. He had two jars, one with a net top so air, but no flies could enter and one open top. What he thought was true- the meat in the jar with the net top did not have maggots. It showed that flies come from the eggs of other flies -
(1700-1800) Spontaneous Generation?
Spallanzani believed that microorganisms came from other microorganisms and not from the air. He boiled two beakers of clear broth. He sealed the tops of some flasks and left others open. The open flask contained microorganisms while the sealed flask did not. -
(1800-1900) Pasteur
He helped prove Spalanzoni's experiment. He created the curve necked flask to allow air inside the flask but not microorganisms. Both flasks remained clear, but when the curved neck was broken the flask became cloudy because microorganisms entered. People stopped trying to argue with Spallanzoni's experiment. Biogenisis is now a major study in science. -
(1600-1700) Microscopes
Scientists began to use microscopes. This tool enabled them to see very small things that the eye could not. -
(1920s) Oparin's Theory
Oparin thought that the early atmosphere contained things such as water, ammonia and hydrogen. He believed that when these molecules reacted, they resulted in macromolecules that were necessities for life, such as protein. -
(1949) Radiometric Dating
It is a method used to figure out how old something is. This is done by looking at the radioactive isotope to see how much it has decayed. The amount of raddioactive isotopes is measured to see how old the material is. -
(1953) Testing Oparin's Hypotheis-Urey and Miller
They tested Oparin's hypothesis. They set up a chamber that had the gasses Oparin thought were initially in Earth's atmosphere. The gasses circulated and electric sparks gave off energy that was used to produce the chemical reactions Oparin had hypothesized. The results showed a variety of organic compounds including amino acids. They had proved Oparin's hypothesis correct. -
(1950s60s) Fox's Research
He researched the physical stuctures that might have become the first cells, helping people to understand how they came to be. -
(1966) Lynn's Research
This research showed that early forms of prokaryotic cells might have developed based on mutually benficial relationships. She fouhnd that organelles and bacteria are very similar. She showed that cells use eachother as sources when in need of something, such as energy. -
(Early 1980s) Cech's Research
Thomas Cech discovered the ribosome. His findings heled support the thoery that life might have started by self-replication RNA molecules.
