EOSC 326 Study Guide - Midterm Guide: Cambrian Explosion, Ediacaran Biota, Cambrian Stage 2
Document Summary
The cambrian explosion is the sudden appearance of large fossils at the base of. Scarcity of precambrian fossils: possible reason : the majority of precambrian life forms are soft bodied and don"t fossilize as well as their hard-part counterparts in the cambrian. Majority of fossil invertebrates appearance during cambrian : arthropoda, brachiopoda, chordata (including the vertebrates, echinodermata, hemichordata (including the graptolites, mollusca. Only the cnidaria and the porifera have been positively identified from the vendian (late. Precambrian): fuse of cambrian explosion the molecular clock technique now suggests that the roots of the cambrian explosion do lie in the precambrian but probably with much of the diversification occurring in the lower and middle cambrian. One of the most obvious features of the cambrian explosion is the appearance of mineralized shells. It is now known that biomineralization occurred before the base of the cambrian alongside the ediacaran biota: driver of cambrian explosion.