The Cambrian Explosion
The Cambrian explosion established virtually all the major animal body forms that would exist thereafter, including many that became extinct. ~ English anthropologist Roger Lewin
Pannotia breaking up led to the abrupt disappearance of Ediacaran biota. The radiative revolution of the Cambrian (542–485 MYA) followed. It was facilitated by a surge in oxygen which incited animal evolution in shallow marine waters. Extreme fluctuations in oxygen during the Cambrian period alternately provoked dramatic diversifications and mass extinctions (during anoxic times).
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Discoveries pertinent to evolutionary biology have at first been typically interpreted within the conventional mindset of the day. Decades or generations may pass before reinterpretation, as Cambrian fossils exemplify.