Geologic Time Scales
Eras
of the Earth
Precambrian
Paleozoic
Era
Cambrian
Period
Ordovician
Period
Silurian
Period
Devonian
Period
Carboniferous Period
Mesozoic
Era
Triassic
Period
Jurassic
Period
Cretaceous
Period
Cenozoic
Era
Tertiary
Period
Quaternary
Period
Geologic
Timeline
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Kevin C. HartzogGeologic Time Scales
Eras of the Earth
Paleontologist have divided Earth's history into eras, periods, and epochs. Monumental events and changes mark the end of one time frame, and the beginning of another. The Precambrian is the first time frame in Earth's history, begining with the birth of the Earth, and ending with an event called the "Cambrian Explosion". An abundance of diverse life found in the Burgess Shell marks the Cambrian Explosion. This explosion was latter seen to be less of a sudden increase in families, and marked more by extraordinarily good conditions for the formation of fossils. Still, that early exclamation still lives with us today. The Cambrian Explosion begins the Paleozoic Era which saw the evolution of mulicellular organisims, and the evolution of shells. The Paleozoic Era ended with a mass exticntion caused by the impact of a comet or asteroid 250mya. The exit of the Paleozoic Era herladed the begining of the The Mesozoic Era, which saw the rise and fall of the dinosaurs. Both dinosaurs and the Mesozoic Era ended when another comet struck the Earth 65mya. This event rose the curtain on the Cenozoic Era, the age of mammals, birds, bony fish, and flowering plants.What event will end the Cenozioc?