The History of Life on Earth (multiply all dates by 1 million)

By RyTheGuy
  • Period: 3800 BCE to 545 BCE

    Archean era

    First living organisms begin to develop, many unicellular.
  • Period: 545 BCE to 495 BCE

    Cambrian

    Life develops organisms that are much more diverse and complex. Some of those include the Trilobite, with a tough, primitive exoskeleton.
  • Period: 495 BCE to 417 BCE

    Ordovician/Silurian Period

    A few organisms began to emerge out of the vast oceans and onto the previously lifeless, desolate landscape. There was a mass extinction event that separated these two periods, believed to be an ice age. After the extinction event, reefs began to flourish. Water levels rise, forming lakes and swampy marshes on land. Plants also flourish along those primitive water ways, and begin to produce oxygen at an alarming rate.
  • Period: 417 BCE to 290 BCE

    Devonian/Carboniferous Period

    The Devonian period is where the oceans began to really kick off. Coral reefs developed greatly. Fish began to specialize and diversify including sharks. The Devonian period also suffered another mass extinction, which wiped out 3/4 of all life on earth. After this mass extinction gave birth to the next era, the Carboniferous. The Carboniferous had the highest levels of oxygen ever on Earth, which allowed the evolution of giant dragonflies, spiders and millipedes, and the first lizards.
  • Period: 290 BCE to 248 BCE

    Permian Period

    The Permian period was the roughest period in geological history. It began after an Ice age, and ended with the most devastating mass extinction ever. This is also when all the landmasses of earth connected to form Pangaea.
  • Period: 248 BCE to 205 BCE

    Triassic Period

    The Mesozoic Era is most famed for being the Era of the Dinosaurs. It began with the Triassic Period, where dinosaurs first began. After the great Permian period, the Earth during the Triassic was a desolate place, mostly made up of dry deserts and grasslands. Pangaea began to break apart into different continents. The Triassic ended in yet another mass extinction, with meteor impacts, floods, and climate change to blame.
  • Period: 205 BCE to 142 BCE

    Jurassic Period

    The Jurassic period recovered very quickly from the mass extinction of the Triassic. The Jurassic period had the most diverse range of organisms on Earth to date. Some of those included the first birds and the Dinosaurs ruled supreme.
  • Period: 142 BCE to 65 BCE

    Cretaceous Period

    The Cretaceous period was the time of the most advanced and famous dinosaurs, including the like of T-Rec and Triceratops. The Earth was fairly warm at the time, with no polar ice caps and high sea levels. (Florida was underwater!) The cretaceous ended in the most famous mass extinction, the one that killed the dinosaurs. Many of the species were already in decline, and the massive meteor was the final blow to most organisms except some reptiles, birds, and the mammals.
  • Period: 65 BCE to 33 BCE

    Paleocene-Oligocene Epoch

    After the mass extinction event of the Cretaceous period, the mammals rose above the ashes of the dinosaurs, who branched off and expanded at a rapid pace, to fill the empty niches left by the dinosaurs. the planet warmed in the Paleocene, and is now beginning to freeze into an ice age.
  • Period: 33 BCE to

    Miocene-Holocene Epoch

    The Miocene began with an ice age, and ended with the beginning of man. After the Miocene, the primates began to stand up right, use tools, and before they knew it, they'd be looking at a timeline leading up to this very point.