3, Starer & Tran, History of Earth

  • (5 BYA) Solar System Started Forming

    (5 BYA) Solar System Started Forming
    The solar system was a swirling mass of gas and dust later pulled together to create the sun. The extra debris collided to form the planets.
  • (4.6 BYA) Earth Formed

    (4.6 BYA) Earth Formed
    The Earth was formed it took 400 million years. Earth formed through all of the extra debris pulling together after the solar syatem formed.
  • (4 BYA) Crystals

    (4 BYA) Crystals
    Earth’s age this was founded by scientists studying the sedimentary rocks in the Earth’s crust, this is the age of the oldest known rocks and crystals.
  • (4 BYA) Half-life

    (4 BYA) Half-life
    The isotopes had unstable nuclei and when through radioactive decay. These are called radioactive isotopes and have a half-life.
  • (3.5 BYA) Stromatolites Fossils

    (3.5 BYA) Stromatolites Fossils
    The age of the oldest found stromatolites fossils.
  • (3 BYA) Life

    (3 BYA) Life
    Forms of life became photosynthetic.
  • (2.2 BYA) O2

    (2.2 BYA) O2
    O2 reached the upper parts of atmosphere where the sunlight is.
  • (2 BYA) O2 Levels

    (2 BYA) O2 Levels
    O2 levels reached today’s levels, helps to protect life from ultraviolet radiation.
  • (1.5 BYA) Aerobic Prokaryote

    (1.5 BYA) Aerobic Prokaryote
    A small aerobic prokaryote began to live and reproduce inside larger prokaryotes through energy synthesis.
  • (1 BYA) O3

    (1 BYA) O3
    Ozone (O3) formed – protected organisms from harmful UV rays so they could exist on land.
  • (Between 1600 -1700) Hooke Discovered Cells

    (Between 1600 -1700) Hooke Discovered Cells
    In 1665, Robert Hooke studied nature by using an early light mcroscope; he discovered cells in a thin piece of cork.
  • (Between 1600 -1700) Redi's Experiment

    (Between 1600 -1700) Redi's Experiment
    In 1668, Francesco Redi conducted an experiment to test his hypothesis that meat kept away from adult flies would stay free of maggots.
  • (Between 1700-1800) Spallanzani's Experiment

    (Between 1700-1800) Spallanzani's Experiment
    In 1700s, Lazzaro Spallanzani concluded that the boiled broth in his experiment became contaminated only when microorganisms from the air entered the flask.
  • (Between 1800-1900) Pasteur's Experiment

    (Between 1800-1900) Pasteur's Experiment
    By the mid-1800s, Louis Pasteur conducted an experiment to answer objections to Spallanzani’s experiment & reasoned that the contamination was due to microorganisms in the air.
  • (Between 1900- present) Oparin’s Hypothesis

    (Between 1900- present) Oparin’s Hypothesis
    In the 1920s, Soviet Oparin proposed that at high temperatures, ammonia, hydrogen gas, water vapor, & compounds made of hydrogen and carbon, might have formed simple organic compounds like amino acids.
  • (Between 1900- present) Urey & Miller's Experiment

    (Between 1900- present) Urey & Miller's Experiment
    In 1953, Stanley Miller and Harold Urey set up an experiment using Oparin’s hypothesis as a starting point. They sent electrical currents through gases that were believed to be Earth's early atmosphere. When the gases cooled, they thickened to make a salt water-like liquid that had things in it like amino acid, what is found in present-day cells.
  • (Between 1900- present) Discovery of Microspheres

    (Between 1900- present) Discovery of Microspheres
    During the 1960s, Sidney Fox founded microspheres and did research on the physical structure of cells.
  • (Between 1900- present) Endosymbiotic Theory

    (Between 1900- present) Endosymbiotic Theory
    In 1967, Lynn Margulis postulated the endosymbiotic theory, which is the theory that the mitochondria and chloroplasts contained within modern animal and plant cells were once free living bacteria that were engulfed by another bacterial cell leading to the eukaryotic cell.
  • (Between 1900- present) Discovery of RNA Acting As Ribozyme

    (Between 1900- present) Discovery of RNA Acting As Ribozyme
    In 1989, Thomas Cech and his research group did the work leading to the discovery that RNA can self-splice and thus can act as a ribozyme.