Period 4, Thompson and High

  • (5 Billion Years Ago) Solar System Begins to Form

    (5 Billion Years Ago) Solar System Begins to Form
    Five billion years ago, the Earth was a swirling mass of gas and dust, the solar system began form. Due to gravity pulling the dust and gas together, the sun formed.
  • (4.6 Billion Years Ago) Earth Begins to Form

    (4.6 Billion Years Ago) Earth Begins to Form
    The Earth began to form 4.6 billion years ago. Space debris collides with one another because of graviational forces. These collisions generate large amounts of thermal energy.
  • (4 Billion Years Ago) Organic Molecules Formulate and Earth Completes forming

    (4 Billion Years Ago) Organic Molecules Formulate and Earth Completes forming
    The Earth completed forming. Organic molecules form by the heating and cooling of atmospheric gases. They are Archae, similar types of cells, the first to populate the earth. This was confirmed by the Miller-Urey experiment.
  • (3.5 Billion Years Ago) Stromatalites Existed

    (3.5 Billion Years Ago) Stromatalites Existed
    Stromatalites existed 3.5 Billion Years Ago. They are formed by the cementation of microorganisms, especially cyanobacteria.
  • (3 Billion Years Ago) Life Forms Begin to Become Photosynthetic

    (3 Billion Years Ago) Life Forms Begin to Become Photosynthetic
    Three billion years ago, lifeforms on Earth begin to be able to perform photosynthesis. Photosynthesis is a process used by autotrophic organisms to generate food using the sun,
  • (2.2 Billion Years Ago) Earth's Geography

    (2.2 Billion Years Ago) Earth's Geography
    Roughly two billion years ago, the Earth's geography came to look much as it does in present day.
  • (2 Billion Years Ago) Oxygen

    (2 Billion Years Ago) Oxygen
    Two billion years ago, earth's oxygen levels reached those of present day.
  • (1.5 Billion Years Ago) Mitochondria Formed

    (1.5 Billion Years Ago) Mitochondria Formed
    One and a half billion years ago, a mitochondria was formed when an aerobic prokaryote was engulfed inside of an anerobic prokaryote.
  • (1 Billion Years Ago) Ozone

    (1 Billion Years Ago) Ozone
    The Ozone layer was formed one billion years ago by the release of gases into the atmosphere. It protects organisms from harmful uv rays so they can exist on land.
  • (1665) Microscope

    (1665) Microscope
    The light microscope was invented by Robert Hooke. It uses optical lenses to magnify objects by bending light rays. He tested it by looking at a thin slice of cork from the bark of a cork oak tree.
  • (Mid 1700's) Spallanzani's Experiment

    (Mid 1700's) Spallanzani's Experiment
    Lazzaro Spalanzani performed an experiment to test wether or not organisms spontaneously generated in a substance, or if they entered the substance from the air.
  • (1864) Pasteur’s Experiment

    (1864) Pasteur’s Experiment
    This experiment was based off the findings of Lazzaro Spallanzani. Louis Pasteur took two flask and boiled broth in both, except unlike the Spallanzani experiment he added a curved neck to one flask. After many months the broth in the flask without a neck or any covering became very cloudy; however, the flask with the curved neck was clear and the curve in the neck had collected all the bacteria and organisms that tried to enter the broth. Even to this day the flask with the curved neck still ha
  • (1668) Redi's Experiment

    (1668) Redi's Experiment
    The experiment started with two containers of rotting meat. One container had one container that was not covered and another one that was covered. The container that was not covered and exposed to flies developed maggots however the container that was not exposed to the flies did not produce new flies. This experiment was performed by an Italian doctor that would later disprove the idea of spontaneous generation.
  • (1905) Radiometric dating

    (1905) Radiometric dating
    This type of dating is primarly used to date materials like rocks. The most known use of radiometric dating was to date the Earth itself. Radiometric dating uses the comparisons between radioactive isotopes and its decay life.
  • (1920’s)- Oparin’s Hypothesis

     (1920’s)- Oparin’s Hypothesis
    This hypothesis was made by Alexander Oparin, a soviet biochemist, and an American John B. S. Haldane in the 1920’s. They hypothesized that at high temperatures organic compounds will form amino acids. Once the Earth cooled and the water vapor created lakes, and seas the organic compounds collected in the water. Over time the simple beginning organic compounds would go through chemical reactions to make the compounds more complex.
  • (1952) Urey- Miller Experiment

    (1952) Urey- Miller Experiment
    The experiment was conducted by Stanley Miller and Harold Urey. This experiment had the conditions hypothesized by scientist that the early Earth. In the experiment there was a chamber containing the hypothesized original gases and it also had electric shocks acting as lightening. Miller and Urey created this experiment to test the hypothesis of Alexander Oparin which was that the conditions on the early Earth created reactions that caused organic compounds to be
  • (Early 1960's) Fox

    (Early 1960's) Fox
    Sidney Fox and other reaserchers were the first to grow cells in a lab. These cells grew from simple organic materials harvested in the lab. The cells were mircrospheres which are circle like objects made up of mostly proteins molecules and were organized as a membrane
  • (1966) Lynn Margulis

    (1966) Lynn Margulis
    Lynn Margulis was the first to develop a well known and correct theory on how organelles came to be. She stated that mitochondria came from an endosymbiosis (a smaller prokaryotic inside a larger prokaryotic cell where it lives and reproduces) aerobic prokaryotes since the mitochondria do the breathing for the cell. Also she developed the theory that chloroplast came from endosymbiosis photosynthetic cyanobacteria, which now perform photosynthesis for the cell.
  • Thomas Cech (1982)

    Thomas Cech (1982)
    Cech found that a certain type of RNA found mostly in unicellular Eukaryotic cells can act in similar ways as an enzyme. He used the word “ribozyme” for his new discovery. It was then discovered then this “ribozyme” could act as a catalyst and start up certain chemical reactions.