BIO 3102 Study Guide - Symmetry In Biology, Trilobite, Bryozoa
Document Summary
Polyp this is the sessile stage in the cnidarian life cycle. Carbon dioxide the levels of this greenhouse gas fluctuate dramatically near the end of the proterozoic eon alternating between low levels and a frozen planet and high levels. Burrow the cambrian fauna were the first to do this tapped into a food resource on the ocean"s bottom that no one had been able to use. Trilobite this arthropod was abundant during the cambrian and although it survived into the ordovician, it is now extinct. Tubefeet the main locomotory structures used by echinoderms. File the radula resembles this type of tool found in a toolbox. Calcium an increase in this mineral in the cambrian oceans may explain the sudden appearance of the shelly animals in the fossils of the cambrian. Snowball prior to the cambrian, the earth is believed to be completely frozen which gives the theory explaining the phenomenon its name.
