User:Arkuat/Preprehistory
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See also: Timeline of evolution, Geologic timescale#Table of geologic time, History of Earth, Timeline of the universe, Paleontology
| Began (-years) | Name | Events | Duration (years) |
|---|---|---|---|
| -14 E9 | Big bang | Everything? | 0 |
| -14 E9 | Preatomic | Near the beginning of this period, helium nuclei (alpha particles) coalesce from free protons and neutrons. At the end of this period, electrons join with protons and alpha particles to form hydrogen and helium atoms, at which point space becomes transparent to light for the first time. | 300 E3 |
| -14 E9 | Pregalactic | Galaxies are currently thought to have begun forming around 600 million years after the Big bang. See reionization. | 600 E6 |
| -13 E9 | Presolar | 8e9 years of the history of the universe go by, during which all of the atoms in the Solar system (except H and He) form in stars and supernovae of the Milky Way galaxy. | 8000 E6 |
| -4600 E6 | Solar nebula | formation of the Sun and Solar system | 100 E6 |
| -4500 E6 | Hadean | Earth and Moon form from planetesimals at the beginning of this period. See in particular the animation at History of Earth#Moon. | 700 E6 |
| -3800 E6 | Archaean | reducing atmosphere; anaerobic prokaryotes (common ancestors of us and the Archea); continents smaller than they are today because Earth's thermal heatflow three times higher than today | 1300 E6 |
| -2500 E6 | Paleoproterozoic | The Oxygen Catastrophe. Green bacteria (ancestors of chloroplasts as well as of contemporary green bacteria) begin to produce free diatomic oxygen which floods the Earth's atmosphere and oceans. To the Archea, oxygen is a potent toxin, and they retreat to something like their contemporary habitats. The ancestors of mitochondria and contemporary aerobic bacteria probably arose around this time as well. | 900 E6 |
| -1600 E6 | Mesoproterozoic | Sex and Rodinia. See Eukaryote#Origin and evolution. | 700 E6 |
| -900 E6 | Neoproterozoic | Algae and sponges and cnidaria, oh my. Sturtian and Marinoan glaciations, AKA Snowball Earth. Rodinia breaks up toward end of this period. | 466 E6 |
| -543 E6 | Cambrian | The great radiation of animal phyla probably happened during the late Neoproterozoic, but most of the fossil record of it was deposited during this time period. | 50 E6 |
| -490 E6 | Ordovician | Appalachians form (see Taconic orogeny), trilobites, brachiopods, (Gondwana forms?) | 50 E6 |
| -443 E6 | Silurian | Plants and arthropods invade land, Laurasia starts to form | 35 E6 |
| -408 E6 | Devonian | First forests (of tree-ferns) appear. Plant/insect coevolution begins. Great radiation of bony fishes. | 50 E6 |
| -340 E6 | Carboniferous | Lignin-producing plants spread into vast forests. Trilobites become rare. Giant amphibians and giant dragonflies. (Urals form?) | 60 E6 |
| -280 E6 | Permian | One continent Pangaea and one ocean Panthalassa. First modern conifers. Period ends with a great extinction. | 29 E6 |
| -250 E6 | Triassic | First flowering plants, first flying vertebrates (pterosaurs). Pangaea endures as a single supercontinent. Massive volcanic eruptions (and extinctions) toward end of period as Pangaea begins to break up. | 46 E6 |
| -200 E6 | Jurassic | Great radiation of dinosaurs. Modern continents begin to form. | 60 E6 |
| -135 E6 | Cretaceous | India still joined to Africa, but other continents as now, although in different positions. Dinosaurs dominant. First adaptive radiation of birds. Great angiosperm radiation. Ends with the notorious Cretaceous-Tertiary extinction event. | 70 E6 |
| -65 E6 | Tertiary (i. e. Paleogene and almost all Neogene) | Great radiation of mammals and further reradiation of birds. Gradual cooling trend, retreat of shallow continental seas. | 63 E6 |
| -2 E6 | Quaternary (i. e. very recent Neogene) | See below. | 2 E6 |
