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The Cambrian explosion (also known as Cambrian radiation [1] or Cambrian diversification) is an interval of time beginning approximately in the Cambrian period of the early Paleozoic, when a sudden radiation of complex life occurred and practically all major animal phyla started appearing in the fossil record.
The Great Ordovician Biodiversification Event (GOBE) was an evolutionary radiation of animal life throughout [1] the Ordovician period, 40 million years after the Cambrian explosion, [2] whereby the distinctive Cambrian fauna fizzled out to be replaced with a Paleozoic fauna rich in suspension feeder and pelagic animals.
The Ordovician (/ ɔːr d ə ˈ v ɪ ʃ i. ə n,-d oʊ-,-ˈ v ɪ ʃ ən / or-də-VISH-ee-ən, -doh-, - VISH-ən) [9] is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon.
Oklahoma was a terrestrial environment for most of the ensuing Mesozoic era. [3] The Late Triassic Dockum Group of western Oklahoma preserved remains of archosaurs and temnospondyls, although its fossil record is restricted to a narrow region of the panhandle and is far sparser than the equivalent records in Texas, New Mexico, and Arizona. [98]
Volcanic activity, particularly that of large igneous provinces, has been speculated to have been the cause of the environmental crisis. [3] The emplacement of the Namaqualand–Garies dykes in South Africa has been dated to 485 mya, the time at which the Cambrian–Ordovician extinction event occurred, although there remains no unambiguous evidence of a causal relationship between this ...
The end-Botomian mass extinction event, also known as the late early Cambrian extinctions, refer to two extinction intervals that occurred during Stages 4 and 5 of the Cambrian Period, approximately 513 to 509 million years ago.
The end-Ediacaran extinction is a mass extinction believed to have occurred near the end of the Ediacaran period, the final period of the Proterozoic eon. Evidence suggesting that such a mass extinction occurred includes a massive reduction in diversity of acritarchs, the sudden disappearance of the Ediacara biota and calcifying organisms, and the time gap before Cambrian organisms "replaced ...
By the end of the Cambrian the sea was shallow and the climate dry. Although marine life was diverse during the Cambrian little is known about Ohio's Cambrian inhabitants because the only specimens known were found in core samples. [2] During the Ordovician Ohio was covered in a warm shallow sea that was deepest in the eastern half of the state.