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Jan 1, 1111
Paleozoic
The paleozic era lasted 540 to 250 millions years ago. -
Jan 1, 1112
Geography
Paleozoic paleocartographers have somehow fallen into the habit of placing this reference longitude slightly east of Greenland. -
Jan 1, 1113
Cambrian Era
-the Cambrian period ranges from 543-510 million years ago -
Jan 1, 1114
The beining of the cambrian
The International Commission on Stratigraphy decided to date it to 542 ± 0.3 million years ago, based on a carbon excursion that can be precisely dated to that time. It ends about 490 million years ago. -
Jan 1, 1115
Earth early days during paleozic Era
During the Cambrian period the world was largely covered by epeiric seas, and existing organisms were entirely marine -
Jan 1, 1116
The composition of the atmosphere
he composition of the atmosphere has continued to slowly change, mostly due to the increase of oxygen produced by photosynthetic algae floating on the ocean. By the Paleozoic, the composition of the air has reached something like what we breathe now: about 4/5 nitrogen, 1/5 oxygen, and small amounts of carbon dioxide, water vapor, and other gases -
Jan 1, 1117
Land plants
Land plants appeared near the end of the Ordovician and for the first time we see the green of land plants in our global view. -
Jan 1, 1118
Fossils After death
We can follow the development of life in detail during the Paleozoic, because at the beginning of that Era, life forms developed hard parts like shells, teeth, bones, and woody parts that were easily preserved as fossils. -
Jan 1, 1119
trilobites
Many life form were alive during the paleozoic Era such as Trilobites,brachipods,archaeocyahids,echinoderms,tabulate, rugose,corals as show in these pictures -
Jan 1, 1120
Brachiopods
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Jan 1, 1121
Archaeocyathids
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Jan 1, 1122
Tabulate
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Jan 1, 1123
Rugose Corals
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Jan 1, 1124
Extinctions
The Paleozoic was also marked by several mass extinctions: geologically short periods of time during which large numbers of life forms died out. Mass extinctions occurred at the end of the Ordovician, the Devonian, and the worst one of all at the end of the Permian, when about 95% of all life on Earth died!
