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541 BCE
Cambrian Period- 541 - 485.4 MYA
541 million years ago an increase of oxygen occured. -
485 BCE
Ordovician Period- 485.4 - 443.8 MYA
Most of the world's land was collected into the southern supercontinent Gondwana. -
443 BCE
Silurian Period- 443.8 - 419.2 MYA
Underwater life thrived. -
419 BCE
Devonian Period- 419 - 358.9 MYA
Aquatic life walked on the bottom of shallow water estuaries. -
358 BCE
Carboniferous Period- 358 - 298.9 MYA
Its vast swamp forests produced the coal from which the term Carboniferous, or "carbon-bearing," is derived from. -
298 BCE
Permian Period- 298 - 251.9 MYA
The diversification of the early amniotes into the ancestral groups of the mammals, turtles, lepidosaurs, and archosaurs. The world at the time was dominated by two continents known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa. -
251 BCE
Triassic Period- 251 - 201.3 MYA
Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Therapsids and archosaurs were the chief terrestrial vertebrates during this time. -
201 BCE
Jurassic Period- 201 - 145 MYA
Two extinction events occurred during this period: the Pliensbachian-Toarcian extinction in the Early Jurassic, and the Tithonian event at the end. -
145 BCE
Cretaceous Period- 145 - 66 MYA
a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites and rudists. During this time, new groups of mammals, birds, and plants, appeared. -
66 BCE
Tertiary Period- 66 - 2.58 MYA
The Tertiary is no longer recognized as a formal unit by the International Commission on Stratigraphy, but the word is still widely used. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start of the Cenozoic Era, and extended to the beginning of the Quaternary glaciation at the end of the Pliocene Epoch. -
2 BCE
Quaternary Period- 2.5 - 0.012 MYA
The continents slowly inched as the forces of plate tectonics push and tugged them. The slight shifts cause ice ages. The last ice age ended about 10,000 years ago. Sea levels rose rapidly, and the continents achieved their present-day outline.
