GEOL 1003 Lecture : Early Paleozoic Student Notes
Document Summary
Early paleozoic = cambrian & ordovician: cambrian explosion early cambrian life branched marking at the base of the cambrian. *development of skeletons: development of soft tissue: supports soft tissue, facilitates locomotion, response to predation. Exoskeleton-poor defense from predators that swallow whole organism. *lowermost cambrian: simple tube, or vase shaped skeletal fossils, first teeth seen. *tommotio fauna:short lived(3-4 mys) and most have no relation to post cambrian animals. Fauna are first mollusks, first brachiopods. (ex: monoplachophoran mollusks). *large animals with skeletons: trilobites- arthropods w?calcfied segmented skeletons. Means that earliest trial. s could not not roll up and protect their body. Ordovician life (444-488gma) got its name from britain. Here there"s very dramatic radiation of marine organisms(oldest complete fish fossils), terminal mass extinction! Graptolites: zooplankton with saw blade fossil form; and nautiloids-swimming, predatory cephalopods(some squids) Rugose and tabulate corals that replaced particular orgs. Life in sediment changed: burrowers expanded and diversified (new worms!)
