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Prehistoric Scratchpad

Era from which we have the first multicellular fossils.

Neoproterozoic Era Web Pages[]


  • Phanerozoic Eon (0.542-0.0 BYA) - The current geological eon, and the one where abundant animal life is present.
    • Paleozoic Era (541-252.2 MYA) - Early age of the animals.
      • Cambrian Period (541-485.4 MYA) - Period that experienced the greatest explosion in animal life. Took place after Snowball Earth and a mass extinction of the pre-cambrian complex life. Many types of modern life are represented in this period, including Arthropods (trilobites, already diverse), molluscs (sea shells), echinoderms (sea urchins, starfish), and the oldest vertebrates (Haikouichthys). The development of the complex eye is thought to have originated at this time, accelerating evolution.
        • Event: A radiation of complex life and the introduction of many hard bodied species. Many of the genera of animals started because of this. May be linked to a mechanism where mineral contents of the seas increased dramatically. Life would expel this and form shells, bones, and teeth.
  • Proterozoic Eon (2.50-0.541 BYA) - Eon where there was abundant microbial life in an oxygenated atmosphere.
    • Neoproterozoic Era (1000-540 MYA) - Era from which we have the first multicellular fossils.
      • Ediacaran Period (635–541 MYA) - A period of the beginnings of complex multicellular life that coincided with a slow 1% to 10% modern level 100 MY rise in Oxygen levels. Followed the Sturtian Glaciation and saw increase in Oxygen contents due to Sturtian glaciers melting and adding nutrients to the sea floor. Oxygen went from 1% to present day (enough to support small sponge-like creatures) to 10% in 100 Million Years (shortly into Cambrian). A relatively mild glaciation interrupts this period, after which oxygen levels rose again, and strange pizza-shaped creatures lived on the seafloor.
        • Event: Gaskiers Glaciation (582-580 MYA) - Perhaps the most recent snowball Earth Period. Preceded the appearance of Ediacaran biota.
      • Cryogenian Period (720–635 MYA) - A period dominated by the greatest Ice Ball Earth glaciations, with a respite between.
        • Event: Marinoan Glaciation (650-635 MYA) - The most severe Snowball Earth period, sometimes called "The Snowball Earth". Oxygenation occurred after this glaciation due to melting glaciers halted a decline in oxygen levels and started an increase.
        • Event: Sturtian Glaciation (720-660 MYA) - The longest lasting Snowball Earth period.
      • Tonian Period (1000–720 MYA) - A period that saw the end of the "Boring Billion" and the continued evolution of simple life. Eukaryote predation may have driven its diversification.
    • Mesoproterozoic Era (1.6-1.0 BYA) - Era that saw the development of sexual reproduction.
    • Paleoproterozoic Era (2.5–1.6 BYA) - Era that saw the Great Oxygenation Event, followed by the first Snowball Earth period.
      • Event: Boring Billion (1.8-0.75 BYA) - Period where oxygen levels dropped and continued to decline and evolution stagnated. During this time, the Earth remained warm with no glaciations, despite supercontinent formation and breakup. The period shows unprecedented and unrepeated stability. Starts with development of Eukaryotes and ends with their diversification. Plate tectonics were stable during this time (little destruction of crust) and restarted at the end.

Neoproterozoic Era In the News[]

Life exploded on Earth after slow rise of oxygen[]