Biology 2581B Study Guide - Quiz Guide: Cambrian Explosion, Ediacaran Biota, Polychaete
2 May 2020
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Document Summary
Major patterns in the history of life the phanerozoic eon. Only a few representatives of modern macroscopic phyla (cnidaria, porifera) known from late precambrian faunas ediacaran biota (565 544 mya) found in south australia. Major explosion of skeletonised marine forms at about 530 mya during the cambrian explosion. Many modern phyla and classes of marine life appeared (crustacea, annelids, mollusca, First appearance of brachiopods, common fossils that resemble bivalves, but are unrelated to them (most now extinct) Prior to discovery only hard shelly" fossils known from cambrian. Discovered by charles walcott (1909) in canadian rockies. Entire marine benthic fauna was buried in a mudslide of low-oxygen sediment. Well preserved presumably because they were entombed by an underwater mudslide. Excellent cambrian fauna, many of which were initially believed to represent extinct phyla (problematica) 520-515 mya. Opabinia, with 5 eyes and proboscis ending in a claw. Wiwaxia, with bladeless spines projecting from coat of scales.
