Geologic TimeLine

  • Cambrian Period

    Cambrian Period
    The Cambrian Period marked a profound change in life on Earth.Living organisms on the whole were small, unicellular and simple. The seas were relatively warm, and polar ice was absent for much of the period.
  • Ordovician Period

    Ordovician Period
    a rich variety of marine life flourished in the vast seas and the first primitive plants began to appear on land. Most of the world's landmasses came together to create the supercontinent of Gondwana, which included the continents of Africa, South America, Antarctica, and Australia. Gondwana drifted south throughout the period, finally settling on the South Pole. Popular animal during this period was the squidlike nautiloids, a type of tentacled mollusk, the nautiloids were effective predators.
  • Silurian Period

    Silurian Period
    animals and plants finally emerge on land. Huge reef systems flourished in the clear, tropical seas. The growth of corals and other marine organisms was stoked by oceans teeming with tiny planktonic creatures. Fish were now diversifying. Creepy-crawlies also began to appear. The first true plants began to take root on land.
  • Devonian Period

    Devonian Period
    Known as the Age of Fishes. There was Shark Ancestors. Plants began spreading beyond the wetlands during the Devonian, with new types developing that could survive on dry land. By the end of the period the first ferns, horsetails, and seed plants had also appeared. Up to 70 percent of marine creatures wiped out. A major asteroid impact has also been suggested.
  • Carboniferous Period

    Carboniferous Period
    Carboniferous coal was produced by bark-bearing trees that grew in vast lowland swamp forests. Vegetation included giant club mosses, tree ferns, great horsetails, and towering trees with strap-shaped leaves. some very poisinous creatures were the dragonflies that grew to the size of seagulls. Amphibian Evolution.
  • Permian Period

    Permian Period
    ended in the largest mass extinction the Earth has ever known. Early reptiles were well placed to capitalize on the new environment. Other mammal-like reptiles known as therapsids found an internal solution to keeping warm. The Permian extinction—the worst extinction event in the planet's history—is estimated to have wiped out more than 90 percent of all marine species and 70 percent of land animals.
  • Triassic Period

    Triassic Period
    violent volcanic eruptions, climate change, or perhaps a fatal run-in with a comet or asteroid—had triggered the extinction of more than 90 percent of Earth's species. Tremendous change and rejuvenation. All the Earth's landmasses had coalesced to form Pangaea, a supercontinent shaped like a giant C that straddled the Equator and extended toward the Poles. The first corals appeared. Evolution of dinosaurs and the first mammals in the late Triassic
  • Jurassic Period

    Jurassic Period
    Dinosaurs, birds, and rodents. The oceans, especially the newly formed shallow interior seas, teemed with diverse and abundant life. The earliest known bird, Archaeopteryx, took to the skies in the late Jurassic, most likely evolved from an early coelurosaurian dinosaur. Huge Dinosaurs.
  • Cretaceous Period

    Cretaceous Period
    dramatic changes to the flora and fauna. New Dinosaurs. Other creatures, such as frogs, salamanders, turtles, crocodiles, and snakes, proliferated on the expanded coasts. The largest pterosaur known soared overhead though the group as a whole faced ever stiffening competition from fast diversifying birds. Rays and modern sharks became common. rapid dispersal of flowering plants . Much of this rich life including all dinosaurs, pterosaurs, pliosaurs, and ammonites perished in the extinction event
  • Tertiary Period

    Tertiary Period
    During this time mammals diversified quickly. Some examples are marsupials, insectivores, bears, hyenas, dogs, cats, seals, walruses, whales, dolphins, early mastodons, hoofed mammals, horses, rhinoceroses, hippopotamuses, oreodonts, rodents, rabbits, monkeys, lemurs, apes, and humans .
  • Quaternary period

    Quaternary period
    Quaternary is often considered the "Age of Humans." The first modern humans evolved in Africa about 190,000 years ago and dispersed to Europe and Asia and then on to Australia and the Americas. Whales and sharks ruled the sea. Climate change. Ice age ended.