Geologic Time Scale

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Created by
Zeena Basilio

Cards (22)

  • Precambrian

    No fossil records
  • Hadean

    Earth's earliest history, molten surface, volcanism, and asteroid impacts
    No recorded fossils
  • Archean

    Fossils of earliest primitive life-forms: prokaryotic microbes from Archea and Bacteria domain
  • Proterozoic

    First eukaryotes and multicellular organisms
    Single-celled anaerobic prokaryotes replaced by photosynthetic ones
  • Period: Cambrian

    Explosion of life called CAMBRIAN EXPLOSION
    trilobites and brachiopods
  • Period: Ordovician

    1st great extinction due to ice caps
    Marine invertebrates (corals and trilobites)
  • Period: Sillurian

    Shortest period in Paleozoic era
    1st land plants, freshwater fish, jaw-ed fish and spread of jawless fish
  • Period: Devonian

    Extinction of marine animals (jawless fish and placoderm)
    Fishes, evergreens, and ferns dominated
  • Period: Carboniferous
    Swamps (where coal is produced hence the name)
    "Age of Amphibians"
  • Period: Carboniferous-Mississippian

    1st appearance of amphibians
    "Age of Crinoids"
  • Period: Carboniferous-Pennysylvanian

    Terrestrial advancement
  • Period: Permian

    Formation of Pangea, global warming, and large scale volcanic activity towards the end of this period
  • Period: Triassic

    Shortest period in Mesozoic era
    "Age of Reptiles"
  • Period: Jurassic

    Existence and extinction of dinosaurs
    Meteorite impact costing 80% of life on Earth
  • Period: Cretaceous

    1st ceratopsian and pachycephalosaur dinosaurs
    "Age of Dinosaurs"
  • Epoch: Paleocene

    Rapid proliferation and evolution of mammals
    No more dinos
  • Epoch: Eocene

    Animals we see today made their 1st appearance
    Changes in ocean/air circulation
  • Epoch: Oligocene

    Tropical forests condensed along the equator
    Grassland expansion
    Birds and rodents
  • Epoch: Miocene

    Kelp forest and grassland ecosystems
    Golden age of apes and hominids
  • Epoch: Pliocene

    Global cooling after Miocene's warming resulting in spread of grassland and savannah
    2nd appearance of homo
  • Epoch: Pleistocene

    Ice age
  • Epoch: Holocene

    "Age of Man"