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Hadean
The sun formed within a cloud of gas and dust, imploding by a gravitational compaction until it began undergo nuclear fusion and give off light and heat. Surrounding particles began to coalesce by gravity into larger lumps which continued to planets. Left-over material formed asteroids and comets. Sometime during the first 800 my of its history, the surface of the earth changed from liquid to solid. Erosion and plate tectonics has robably destroyed all of the solid rock older than 3.8 by. -
Archean Eon
The Archean eon, had a very different envirmnet. More than one billion years of the Archean life was bacterial, and early on for the firat life. All life during the more than one billion years of the Archean was bacterial. The Archean coast was home to mounded colonies of photosynthetic bacteria- stromatolites.
Spanning 1.5 billion years and subdivided into four eras
eoarchean 2800-500 mya
Mesoarchean 3200-2800 mya
Paleoarchean 3600-3200 mya
Eoarchean 4000-3600 mya -
Proterozoic Eon
It took nearly 4 thousand my before the first animals would leave their traces on the planet. This span makes up about seven-eighths of the Earth's history. The most important events in biological history took place. Life arose, the first tectonic plates came and began to move, eukaryotic cells evolved, the atmosphere became enriched in oxygen, and just before the end, the first animals evovled.
Neoproterozoic 1000 - 542 mya
Mesoproterozoic 1600 - 1000 mya
Paleoproterozoic 2500-1600 mya -
Paleozoic Era
The Paleozoic has two of the most important events in the history of animal life.
Beginning of era- multicelled animals underwent a dramatic "explosion" in diversity. Almost all living animal phyla appeared within a few millions of years.
Enf of ear-largest mass extinction in history wiped out approximately 90% of all marine animals. Halfway in between, animals, fungi, and plants colonized the land.
Permian 299.0 -251.0 mya
Carboniferous 359.2 - 299.0 mya
Devonian 416.0 - 359.2 mya
Silurian
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Mesozoic Era
Mesozoic was the time during which the world changed drastically from what had been seen in the Paleozoic. Dinosaurs evolved in the Triassic, but were not diverse until the Jurassic. Except for birds, dinosaurs became extinct at the end of the Cretaceous.
The Mesozoic era was also a time of change among plant life. Cretaceous 145.5-65.5 mya
Jurassic 199.6-145.5 mya
Triassic 251-199.6 mya -
Cenozoic Era
The Cenozoic Era is the most recent of the three major subdivisions of animal history. The other two are the Mesozoic and Paleozoic Eras. The Cenozoic spans about 65 million years, from the end of the Cretaceous Period and the extinction of non-avian dinosaurs to the present. The Cenozoic is also called the Age of Mammals, because the largest land animals have been mammals during that time. Quaternary 2.6 million years ago to present
Neogene 23.03 to 2.6 mya
Paleogene 65.5 to 23.03 mya
