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Period: 445 BCE to 443 BCE
The first exstinction
An early phase affecting graptolites, brachiopods, and trilobites occurred prior to the end of the Ordovician Period, before the major fall in sea level. A second phase of extinction occurred as sea levels fell because of the onset of glaciation over the African and South American portions of Gondwana. 444 million years and ended in 443 source: https://www.britannica.com/science/Ordovician-Silurian-extinction -
Period: 375 BCE to 360 BCE
The second extinction
A major extinction, the Kellwasser event, occurred at the boundary that marks the beginning of the last phase of the Devonian period, the Famennian faunal stage (the Frasnian–Famennian boundary), about 375–360 million years ago. Overall, 19% of all families and 50% of all genera became extinct. source : https://en.wikipedia.org/wiki/Late_Devonian_extinction -
Period: 250 BCE to 250 BCE
The third excision
The Permian layers contain abundant animal fossils and fossilized traces of animals, while the Triassic layers are almost devoid of fossils, suggesting a mass extinction event occurred 250 million years ago, at the end of the Permian. source: www.pbs.org/wgbh/evolution/library/03/2/l_032_02.htm -
Period: 201 BCE to 145 BCE
The Fourth exstinction
201.3 million years ago (Mya) to the beginning of the Cretaceous Period 145 Mya.[note 1] The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles. The start of the period is marked by the major Triassic–Jurassic extinction event. source: https://en.wikipedia.org/wiki/Jurassic -
Period: 146 BCE to 66 BCE
The Fifth exstinction
relating to or denoting the last period of the Mesozoic era, between the Jurassic and Tertiary periods.
the Cretaceous period or the system of rocks deposited during it.
singular proper noun: Cretaceous source-www.livescience.com/29231-cretaceous-period.html -
3 BCE
The beginning of life
3 billion years ago life roamed earth.