Geological Eras

  • Period: to

    Precambrian Era

  • First crustal rocks form.

  • Earth's surface is cool enough for liquid water.

  • First known unicellular life appears.

  • Earth's atmosphere starts to become oxygen rich.

  • First known multicellular life appears.

  • First fungi appears.

    First fungi appears.
  • First shelled organisms, such as arthropods and mollusks, appear.

    First shelled organisms, such as arthropods and mollusks, appear.
  • Period: to

    Palezoic Era

  • First possible vertebrates appear.

  • Modern, oxygen-rich atmosphere has formed.

  • First land plants appear.

    First land plants appear.
  • First arthropods appear on land.

  • First amphibians appear.

    First amphibians appear.
  • First reptiles appear.

    First reptiles appear.
  • Formation of Pangaea is complete.

    Formation of Pangaea is complete.
  • Permian mass extinction results from major environmental changes.

  • Period: to

    Mesozoic Era

  • Pangaea begins to break apart.

  • First mammals appear.

    First mammals appear.
  • First primitive birds appear.

    First primitive birds appear.
  • First flowering plants (angiospersm) appear.

    First flowering plants (angiospersm) appear.
  • First modern birds appear.

    First modern birds appear.
  • The last dinosaurs become extinct. Catastrophic meteorite impact occures.

    The last dinosaurs become extinct. Catastrophic meteorite impact occures.
  • Most modern mammal families, hoofed animals, and primates have appeared.

    Most modern mammal families, hoofed animals, and primates have appeared.
  • Period: to

    Cenozoic Era

  • First grasses appear.

    First grasses appear.
  • India collides with Asia, and Antartica drifts over south pole.

  • First early human ancestors appear.

    First early human ancestors appear.
  • Modern Ice Age begins.

    Modern Ice Age begins.
  • Modern humans appear.

    Modern humans appear.