The Geologic Record: The Phanerozoic Eon

Automatic TRANSCRIPT

Fenner azoic is divided up into three eras the paleozoic the mesozoic and the senate zoellick the first period in the paleozoic is the one you might have heard of the cambridge in the cambrian is noted for the sudden appearance of complex lifeforms and animals in the fossil record. This is known as the cambrian explosion. Here's where you'll see many of the trial bites which are really common fossils in fact the appearance of trial bites pretty much defines where the cambrian appears in the geologic record all complex life that we know of in the cambrian was in the see. Nothing yet had come onto land of all the periods. I'll be going over. This is one of the most important to have a grasp on it spans. About fifty five million years from five hundred forty million years ago to about four hundred eighty five million years ago after the cambridge incomes the division period it lasted for forty one million years and went from four hundred and eighty five million years ago to about four hundred forty. Four million years ago it's noted for its continued by diversification fish first appeared during this period and probably the first fish with jaws. These were the first vertebrate animals. There still wasn't any animal life on land yet in order vision that we know of there were lots of volcanoes in meteors during this period as well by some estimates over one hundred times the number of meteor strikes that the earth experiences today the next period is the celerion it goes from four hundred and forty million years ago to four hundred nineteen million years ago what separates the division and the celerion is the or division celerion extinction event. This is the first of the major extinction events in earth's history and the second largest in terms of the number of species that disappeared from the fossil record. The celerion sees the appearance of the very first vascular plants on land as well as the first arthur pod type creatures on land. I should also note that as we get closer to the present the information we have become better the divisions in time become more. Precise and there are more subdivisions. Most of which. I'm not going to be going into. After the slurry incomes the devonian which extended from four hundred nineteen million years ago. Two three hundred fifty nine million years

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