PCB 4674C Lecture Notes - Lecture 20: Burgess Shale, Cambrian Explosion, Paleozoic
Document Summary
1) the ediacaran fauna 565-542 million years. Almost 4 billion years since the origin of the earth, we see the first unequivocal evidence of metazoans (multicellular animals), the ediacaran. Fauna: first found in the medicare hills of australia, now found in other rocks of similar age in other areas. Soft-bodied animals, some of unknown affinity, some appearing very similar to jellyfish, comb jellies (ctenophora), and sponges. Some of the ediacaran fossils may well represent early experiments in multicellularity that have left no living descendants. There are also trace fossils (traces of organismal activities such as trails or burrows) as well as a few isolated fossils suggestive of bilaterally symmetrical animals. Aside from the ediacaran fossils, trace fossils and these few isolated fossils, this is the main evidence for multicellular animals until the cambrian period. The cambrian period, 541 million years ago. The base of the phanerozoic (phaneros=visible or evident, zoic= life).
