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 Automatic translation  Automatic translation Category: Earth
Updated March 14, 2015
  Biodiversity during the Phanerozoic

Image: Evolution of the number of genera (set of species) during the Phanerozoic, according to a 2005 study by Robert A. Rohde & Richard A. Muller (Department of Physics and Lawrence Berkeley Laboratory). The diversity of life seems to fluctuate during the Phanerozoic, this curve shows the apparent changes in marine biodiversity throughout the 542 million years of the Phanerozoic. There are 3 eras in the Phanerozoic, the primary era (542-250 my), the Mesozoic era (250-65 my) and Tertiary (65 my to now). These eras are marked by great mass extinctions, especially one that took place there are 250 my and that took place there are 65 ma. Since the last mass extinction there are 65 my, life has never been more diverse than today.

  Biodiversity during the Phanerozoic

Image: Intensity of mass extinctions in the Phanerozoic. The five major disasters in the history of the Earth occurred at the end of the Cretaceous (End K) at the end of the Triassic (End Tr) at the end of the Permian (End P) in the late Devonian (Late D) and at the end of the Ordovician (End O). Credit image: GNU Free Documentation License.

Major biological crisis Families Genera Species
(≈ −450 million years)



(≈ −370 million years)



Permian - Triassic
(≈ −250 million years)



Triassic - Jurassic
(≈ −205 million years)



Cretaceous - Tertiary
(≈ −65 million years)




Table: The five major disasters in recent Earth history (last 540 ma). These figures are probably biased, but they have the merit of bringing out the Permian-Triassic crisis like the one that was the most devastating and the Cretaceous-Tertiary crisis, the best known and yet least deadly. Successions of volcanic eruptions, ones after the others would they have had an impact on the evolution of biodiversity by participating in mass extinctions?

geological times

Image: Geological aeons, of the Hadean to Phanerozoic, the last 540 million years are the best dated. credit astronoo.

The astronomical unit (au) created in 1958, is the unit of distance used to measure the distances of objects in the solar system.
The value of the astronomical unit represents exactly the distance from the Earth to the Sun (149,597,870,700 m). We will remember about 150 million kilometers.
Mercury: 0.38 au, Venus: 0.72 au, Earth: 1.00 au, Mars: 1.52 au, Asteroid belt: 2 to 3.5 au, Jupiter: 5.21 au, Saturn : 9.54 au, Uranus: 19.18 au, Neptune: 30.11 au, Kuiper Belt: 30 to 55 au, Farout: 120 au, Oort Cloud: 50000 au...
An eon is a very long period of geological time, arbitrary length. The history of the Earth, its formation to the present, is divided into four aeons. The first three (Hadean, Archean, Proterozoic) cover the first 4 billion years of the Earth history. They are sometimes combined into one superéon named "Precambrian". The fourth is the Phanerozoic eon, which began there 542 million years, which is the era of the appearance of small animals, fish and plants on Earth.

1997 © − Astronomy, Astrophysics, Evolution and Earth science.

The first second
The first second
of our history...
Structure of the Earth
in an aquarium...
The frozen Thames in 1677, Little Ice Age
Explanation of the
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Easter Island, collapse of a society
Easter Island, collapse
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explosion of life in the Ordovician
Explosion of life
in the Ordovician...
Cloud cover above the earth
Cloud cover
above the earth...
liquid water, accelerator of chemical reactions
Liquid water, accelerator
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Conditions for the emergence of life
Conditions for the
emergence of life...