Geologic Timescale

  • Cambrian Period: 570-500 MYA

    Cambrian Period: 570-500 MYA
    First multicellular life forms evolving from germs and single celled organisms.
  • Ordovician Period: 500-435 MYA

    Ordovician Period: 500-435 MYA
    Most of the Earth at this time was water, with the exception of a super-continent known as Gondwana. This period was filled with flourishing marine invertebrates.
  • Silurian Period: 435-395 MYA

    Silurian Period: 435-395 MYA
    Temperatures began to rise at this time. Big reefs and other marine mammals begin to flourish. In this period the surface is beginning to have life.
  • Devonian Period: 395-354 MYA

    Devonian Period: 395-354 MYA
    First fish evolved and grew legs. Then began to walk on land. These became known as tetrapods.
  • Carboniferous Period: 345-280 MYA

    Carboniferous Period: 345-280 MYA
    Glaciation started to happen during this period. All of this glaciation caused a small extinction of the marine life that was booming during the devonian period.
  • Permian Period: 280-225 MYA

    Permian Period: 280-225 MYA
    The last period of the Paleozoic Era. This period is most famous for the epoch that ended it. It ended with the largest mass extinction known to science. About 95% of all species on the planet became extinct at once.
  • Triassic Period: 225-195 MYA

    Triassic Period: 225-195 MYA
    It started at the end of the mass extinction of the permian period. And ended with a significantly large extinction as well. It was filled with coral in the Seas and is also where the first flying vertebrates show up (the pterosaurs).
  • Jurassic Period: 195-136 MYA

    Jurassic Period: 195-136 MYA
    Commonly known as the "Age of Reptiles." This period started with a mass extinction, but it did not end with one. This was a time of survival of the fittest, or kill or be killed. Even the herbivores had special evolutionary weapons or defenses to fend off their preditors.
  • Cretaceous Period: 136-65 MYA

    Cretaceous Period: 136-65 MYA
    This period was filled with many birds and flying animals, flowering plants, and was ruled by the dinosaurs.The Cretaceous ended with one of the largest mass extinctions in Earth history, the K-T extinction which wipped out almost all of the animals and life on earth.
  • Tertiary period: 65-1.8 MYA

    Tertiary period: 65-1.8 MYA
    In this period, mammals are beginning to replace reptiles as the dominant life form on land. Earliest recognizable huminoid shows up in this period. Started with the after math of the K-T extinction and ended with the beginning of the most recent ice age to date.
  • Quaternary Period: 1.8 MYA- present

    Quaternary Period: 1.8 MYA- present
    This period started with an Ice age. Many large mammals such as Saber-toothed cats and mammoths became extinct at the end of this ice age. Very little evolution that happened due to this being a significantly young period.