８３ Extinction ＃extinction
“3,500 million years after life birth. The produced living thing is 5 billion 〜 50 billion sorts. It is already exterminated 99.9% of them. Extinction is the universal fate which visits to an organism species” Takashi Tachibana(1940-)
○ Snowball earth
・For about 5〜600 million years at the last Precambrian age Earth entered the time of the snowball earth, and near the equator was covered on ice.
・Most lives on Earth of this time were bacteria.
・The time of the dramatic life evolution "Cambrian explosion" had come after the snowball earth.
・There is also an opinion it is supposed that the earth will be in the state of the snowball earth again in the future.
※The Snowball Earth 
○Extinction of dinosaurs
・6.5million years ago,the collision of a meteorite 10km in diameter to Earth of the dinosaurs planet.
・The clash formed crater of over 250km in diameter(15 ~ 25km depth) in the falling
point(off the Yucatan Peninsula).
・The body of meteorite vaporized by heat of impact vaporization, and dust spreaded into the atmosphere.
・Rock at falling point melted by the heat and splattered around.
・Atmosphere became opaque by dust and sunlight could not reach the surface, the earth was cooling.
・In addition to dinosaurs, many creatures became extinct in order to can not adapt to the rapidly changing environment.
1. Credit: Stocktrek Images, Inc. / Alamy
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