Paleozoic Life - Study Guide 

Paleozoic Life: Cambrian explosion, more diversity and abundance, hard parts (increased preservation), protection, UV, weather, waves, dehydration, predators, increased size, attachment sites for muscles

Lifestyles: location, benthonic, epifauna and epiflora, infauna and inflora, sessile or mobile, pelagic, plankton, nekton; feeding, suspension feeders, herbivores, carnivore-scavengers, sediment deposit feeders

Invertebrates: Cambrian (Sauk sea), trilobites, brachiopods, archeocyathids, Burgess shale; Ordovician (Tippecanoe) -reefs & diversity, bryozoans, corals, rugose, tabulate, bryozoans; Silurian and Devonian (Kaskaskia), similar to Ordovician in diversity, eurypterids, ammonoids (cephalopods); Late Paleozoic, crinoids, fusulinids, sponges

Vertebrates (P. Chordata) :

fish - Devonian is age of fish, placoderm, bony fish, ray-finned fish, lobe-finned fish - Crossopterygian - primitive limbs and lungs, ancestor of amphibians

amphibians - became common by Mississippian and Pennsylvanian, adapted to land, larval stage lived and developed in water

reptiles - appear in Pennsylvanian and Permian but dominate in the Mesozoic, no longer tied to water for reproduction, amniotic egg

Extinctions (followed by adaptive radiation and diversification), end of Ordovician, end of Devonian (cooler water), end of Permian


Describe the Cambrian Explosion. Why might it have occurred? What are the advantages of hard parts?

When were the major extinctions? What might have caused each of them? How did life respond after the extinctions?

What were the major groups of fossils during each period of the Paleozoic. What do they tell about the climate, plates, and fossil succession?

How did amphibians and reptiles have to adapt in order to survive on land?  Why were reptiles able to live in more areas than amphibians?

Identify the following fossils: (common name and Phylum)


Go back to Geology page