X. Paleozoic Life
A. Cambrian explosion
- more diversity and abundance
- hard parts (increased preservation)
- protection
- UV
- weather
- waves
- dehydration
- predators
- increased size
- attachment sites for muscles
B. Lifestyles
- location
- benthonic
- epifauna and epiflora
- infauna and inflora
- sessile or mobile
- pelagic
- feeding
- suspension feeders
- herbivores
- carnivore-scavengers
- sediment deposit feeders
C. Invertebrates
- Cambrian (Sauk sea) - age of trilobites
- trilobites
- brachiopods
- archeocyathids
- Burgess shale
- Ordovician (Tippecanoe) -reefs & diversity
- brachiopods
- corals
- bryozoans
- Silurian and Devonian (Kaskaskia)
- similar to Ordovician in diversity
- eurypterids
- ammonoids (cephalopods)
- Late Paleozoic - Mississippian = age of crinoids
- crinoids
- fusulinids
- sponges
- Extinctions (followed by adaptive radiation and diversification)
- end of Ordovician
- end of Devonian (cooler water)
- end of Permian
D. Vertebrates (P. Chordata)
- fish - Devonian is age of fish
- Ordovician and Silurian
- primitive armored fish
- often jawless
- ostracoderm
- Devonian - age of fish
- placoderm - very large, plated head, predator
- bony fish
- ray-finned fish - similar to modern
- lobe-finned fish - Crossopterygian - primitive limbs and lungs, ancestor of
amphibians
- amphibians - became common by Mississippian and Pennsylvanian
- adapted to land
- full lungs
- strong limbs for gravity
- tougher skin for protection from weather and sun
- different diet
- reproduction still required water
- gooey eggs
- 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
- tough outer shell for protection
- nutrients inside shell
- animal develops fully within the protected shell
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