User: Eric Forste
From open-encyclopedia.com - the free encyclopedia.
See also: Arkuat
Outline of preprehistory
| Began (-years) | Name | Events | - | Duration (years) |
|---|---|---|---|---|
| -14 E9 | Big bang | - | 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. | 3 E5 | |
| -14 E9 | Pregalactic | Galaxies are currently thought to have begun forming around 600 million years after the Big bang | 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 | |
| -5 E9 | - | formation of the Sun and Solar system | - | (?) 500 E6 |
| -4500 E6 | Hadean | Earth and Moon form from planetesimals at the beginning of this period | - | 700 E6 |
| -3800 E6 | Archaean | anaerobic prokaryotes (common ancestors of us and the Archea) | - | 1300 E6 |
| -2500 E6 | Paleoproterozoic | Cyanobacteria 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. | - | 900 E6 |
| -1600 E6 | Mesoproterozoic | sex and Rodinia | - | 700 E6 |
| -900 E6 | Neoproterozoic | algae and sponges (Rodinia breaks up toward end of this period) | - | 466 E6 |
| -543 E6 | Cambrian | great radiation of animal phyla | - | 50 E6 |
| -490 E6 | Ordovician | Gondwana forms, trilobites, brachiopods, (Appalachians form?) | - | 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. Grasses appear toward end of this period. Ends with the notorious Cretaceous-Tertiary extinction event. | - | 70 E6 |
| -65 E6 | Tertiary | Great radiation of mammals and further reradiation of birds. Gradual cooling trend, retreat of shallow continental seas. | - | 63 E6 |
| -2 E6 | Quaternary | See below. | - | 2 E6 |
See also: Timeline of the universe, Timeline of evolution, Geologic timescale, Paleontology
Outline of prehistory and history
- Quaternary Period
- Pleistocene = Paleolithic = Ice age = almost all of the Quaternary. All three periods end suddenly and simultaneously at the end of the Younger Dryas around 96th century BCE.
- Holocene
- Mesolithic, a highly localized and transitory condition
- Neolithic = most of the Holocene, in many locations
- Chalcolithic, around ancient Near East roughly 4th millennium BCE (5 to 6 kiloyears ago)
- Bronze Age: from 33rd century BCE (in Near East, starts later elsewhere) to 10th century BCE
- Iron Age: from 10th century BCE (same caveat) to some arbitrary endpoint
- contemporary (last millennium or so)
The problem with technologically-based chronological terms such as Bronze Age, Iron Age, etc., is that the phenomena involved have locations as well as periods. Thus the Anatolian Iron Age starts around 1200 BCE but the Chinese Iron Age starts a few centuries later. (The particulars are disputed, and this is only an example. The point would be the same if the use of iron originated in China and spread to the west, or were independently discovered later in the west.)
- 10th millennium BCE (End of the Younger Dryas)
- 9th millennium BCE
- 8th millennium BCE
- 7th millennium BCE
- 6th millennium BCE
- 5th millennium BCE
- 4th millennium BCE
- 3rd millennium BCE
- 2nd millennium BCE
- 1st millennium BCE
- 1st millennium
- 2nd millennium
- 3rd millennium
See also: Prehistory, History, Three-age system, Periodization, Archaeology
