alex geology timeline

  • Cambrian 1911-1923

    Cambrian 1911-1923
    most animals lived in the water. The continents were still forming. The weather was starting to warm up.
  • Ordovician 1923-1934

     Ordovician  1923-1934
    first plants grow on land,new animals were evolving in place of the ones that did not survive the cambrian period. Second largest mass extinction of all time ended this period.
  • Silurian 1934-1941

    Silurian 1934-1941
    rising temperatures,Huge reef systems flourished in the clear, tropical seas. underwater animals elvolved with jaws becoming top predators.bugs began to appear on land.drew to a close with a series of extinction events linked to climate change.
  • Devonian 1941-1950

    Devonian 1941-1950
    "the age of the fishes".later species developed into fish-slicing monsters measuring up to 33 feet long. Toward the end of the period the first forests arose.By the end of the period the first ferns, horsetails, and seed plants had also appeared.The main victims of the mass extinction were marine creatures, with up to 70 percent of species wiped out
  • Carboniferous 1950-1961

    Carboniferous 1950-1961
    Africa collided with eastern North America in the late Pennsylvanian, an event that formed the Appalachian Mountains.This period takes its name from the large underground coal deposits. Atmospheric oxygen levels peaked around 35 percent, compared with 21 percent today.
  • Permian 1961-1971

    ended in the largest mass extinction the Earth has ever known.It is estimated to have wiped out more than 90 percent of all marine species and 70 percent of land animals.
    The emerging supercontinent of Pangaea presented severe extremes of climate and environment due to its vast size.
  • Triassic

    gave rise to new creatures, including rodent-size mammals and the first dinosaurs.
  • Jurassic

    at the beggining of the period the breakup of the supercontinent Pangaea continued. large Dinosaurs walked the earth. dry warm weather.
  • Cretaceous

    an extinction of more than half the planet's species happend at the end of the Cretaceous.the shifted continents, expanded coasts, and widened oceans had cooled and moistened the planet's climate.
  • Tertiary

    mammals replaced reptiles as the dominant vertebrates on the planet.