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Solar System Starts to Form (5 BYA)
The sun's gravity pulled in a bunch of rocks, and they started to form planets. The gravity kept them in orbit. -
Period: to
History of the Earth
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Earth Began to Form (4.6 BYA)
Many rocks in orbit colided and stuck together. It kept getting bigger, so it had a stronger gravitational pull. More and more rocks came together and it became a huge planet. -
Estimated Age of Earth (4 BYA)
This is how long its been since the Earth was one solid sphere. -
Archaea Lives (4 BYA)
This is most likely the first form of life to inhabit Earth. It is a microscopic organism that lives in harsh climates. -
Fossils of Stromatolites (3.5 BYA)
Humans discovered fossils of stromatolites, and they are dated back to 3.5 billion years ago. Stromatolites are accretionary layers of rock that form in shallow water because of microoraganisms -
Photosynthetic Organisms (3 BYA)
These organisms give off oxygen as a biproduct of photosynthesis. This is how we are able to live. -
Earth Looks the Way it does Now (2.2 BYA)
The Earth was no longer a lava filled, doomed place of death. Organisms that cannot live in harsh climates can now thrive. -
Oxygen Levels Reached Today"s Levels (2 BYA)
This also helps organisms thrive, like us. This came to be because of the photosynthetic organisms. -
Endosymbiosis (1.5 BYA)
This is when smaller organisms live inside larger ones. A bacteria cell will go inside of a endosymbiont. This is beneficial to both of them. -
Ozone Formed (1 BYA)
The oxygen molecules were floating around in the air. The UV radiation from the sun makes the oxygen recombine to make O3 molecules -
First Microscope (1665)
The first microscope was a light microscope that magnified images through optical lenses that bend the light rays travelling through. -
Redi's Experiment (1668)
Redi conducted an experiment to test biogenesis and spontaneous generation. For the experiment, Redi put meat in the open as a controll group and placed meat in an area where flies could not reach it as the independent. The test was to see if meat that was not touched by flies would produce maggots. The results of the experiment supported biogenisis because the meat without flies did not produce maggots. -
Spallanzani's Experiment (1740)
Spallanzani hypothesised that microorganisms are generated from other microorganisms. The experiment he conducted started by heating flasks filled with broth until the flask was filled with steam and the broth was clear. Then one flask was melted at the top until it was sealed, and the other flask was left open. The results of the experiment also supported biogenesis. The open flask's broth got cloudy while the broth in the sealed flask remained clear. -
Oparin's Hypothesis (1920s)
Oparin hypothesised that Early Earth's atmospere contained ammonia (NH3), hydrogen gas (H2), water vapor (H2O), and hdrogen/carbon molecules such as methane (CH4). He also hypothesised that at high temperatures, these gases could undergo chemical reactions and, fueled by lightning and UV rays, could form organic compounds. -
Radiometric Dating (1950)
Radiometric dating measures the amount of a radioactive compun in an organism and through half-life determines the approximate age of the object. Radiometric dating was "perfected" in 1950, but in 1905 Lord Rutherford suggested the concept of radiometric dating. -
Miller and Urey Experiment (1953)
Miller and Urey took Oparin's hypothesis and tested it. All of the gases that Oparin hypothesised where in early Earth's atmosphere were placed in a closed enviorment of test tubes. The gas was circulated and an electric current was run through to simulate lightning. The results of the experiment were that organic coumpounds, including amino acuids, were formed. -
Sidney Fox (1960)
Fox researched the phsical structures that brought way to cells. Through his research Fox discovered Microspheres and coacervates which were similar to cells except they were not alive and didn't contain organelles. -
Lynn Margulis (1980)
MMargulis theorised that early prokaryotic cells may have developed a mutually beneficial relationship. Margulis theorised that anaeribic cells engulfed aerobic cells. The aerobic cells would provide nutrients and the anaerobic cells would provide protection for the aerobic cells. -
Thomas Cech (1982)
Cech was the first person to prove that RNA can act as a catalyst and not just a carrier of genetic information. This led to the theory that RNA helped create the first organisms. -
Pasteur's Experiment (1844)
People weren't fully convinced by Spallanzani's experiment saying he boiled out the "vital force" in the flasks before sealing one. So, Pasteur repeated Spallanzani's experiment except instead of sealing one flask he gave it a curved top that kept it open but didn't let stuff fall into the broth. The results of the experiment further supported biogenesis. The open flask's broth still got cloudy, however the flask with the curved top remained clear for a year and after the curved top was removed.
