Mass extinctions

By shelbylynn2
  • 4004 BCE

    Beginning of earth

    Beginning of earth
    The earth began 4.5 billion years ago
  • 3007 BCE

    Beginning of life

    Beginning of life
    Life appeared about 3.85 billion years ago
  • 439 BCE

    Ordovician- Silurian extinction

    Ordovician- Silurian extinction
    439 million years ago about 86% of life was wiped out. There were two major events that scientists believed were the cause: glaciation and falling sea levels
  • 364 BCE

    Devonian extinction

    Devonian extinction
    About 364 million years ago almost 75% of species were lost. Trilobites, which survived the Ordovician-Silurian extinction due to their hard exoskeletons, were nearly exterminated during this extinction. Volcanic ash is thought to be responsible for cooling earth’s temperatures which killed off the spiders and scorpion-type creatures. If the late Devonian extinction had not occurred, humans might not exist today.
  • 251 BCE

    Permian- Triassic extinction

    Permian- Triassic extinction
    Occurred 251 million years ago, its considered one of the worst times in history because around 96% of species were lost.
  • 205 BCE

    Triassic- Jurassic

    Triassic- Jurassic
    Happened between 199 to 214 million years ago. The year dinosaurs first appeared on earth
  • 65 BCE

    Cretaceous-Paleogene

    Cretaceous-Paleogene
    A combination of volcanic activity, asteroid impact, and climate change effectively ended 76% of life on earth 65 million years ago.This extinction period allowed for the evolution of mammals on land and sharks in the sea.