User:Universal Life/History

This page outlines major events known to mankind in the history of the universe, in a chronological order. The terminology and the dates given in this page do not always comply with the most recent or major views in the academic chambers. However major differences are indicated through the references. Usually simpler and less technical terms are preferred to the convenience of the reader. Many dates are rounded unless a definitive proof of the date exists.

The abbreviations and symbols included here are listed as follows:
 * BY -- Billion (109) Years
 * BYA -- Billion (109) Years Ago
 * MY -- Million (106) Years
 * MYA -- Million (106) Years Ago
 * + -- More than

Precambrian Supereon

 * 4.54 BYA till 541 MYA

Archaean Eon (4 - 2.5 BYA)
Earth's heat flow was nearly as three times higher than today. Tectonic activity was very high and volcanoes would erupt very often. First life forms (bacteria) and first land masses were formed.

Proterozoic Eon (2500 - 541 MYA)
Earth "calms down" and becomes more stable, the movement of the continents takes a much slower pace. First eukoryatic and multicellular organisms appear in water. Later algae, mosses, fungi, mollusks, sponges and corals appear. First glaciers are formed.

Phanerozoic Eon

 * 541 MYA till Today

Palaeozoic Era (541 - 252 MYA)
The Palaeozoic is the longest of the Phanerozoic eras, and is subdivided into six geologic periods (from oldest to least old): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. It was a time of dramatic geological, climatic, and evolutionary change. The Cambrian Period witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Fish, arthropods, amphibians and reptiles all evolved during the Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, it was dominated by various forms of organisms. Great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America. Towards the end of the era, large, sophisticated reptiles were dominant and the first modern plants (conifers) appeared. The Palaeozoic Era ended with the largest mass extinction in Earth's history, the Permian–Triassic extinction event.