1. Earth History The Paleozoic Era

2. Paleozoic Time (544 - 245 Million Years Ago) n Bracketed by the two most important biological events in Earth’s history: 1.The first appearance of complex organisms 2.The largest mass extinction on the history of the Earth.

3. Paleozoic Time nThere are 7 subdivisions (periods) in the Paleozoic –Cambrian (oldest) –Ordovician –Silurian –Devonian –Carboniferous (Mississippian and Pennsylvanian) –Permian (most recent)

4. Cambrian (544 - 490 million years ago) n During the Cambrian period, most of the major groups of organisms alive today first appeared. n The appearance of organisms was VERY rapid. –The “Cambrian Explosion” –A 5 – 10 million year period of rapid evolutionary development.

5. The Cambrian Seafloor

7. Cambrian Fossils Trilobites Elrathia Peronopsis Ptychagnostus Bathyuriscus Brachyaspidon

8. Cambrian Fossils Brachiopods and Echinoderms Starfish Sand Dollar Brachiopods

9. Unique Fossils n The Burgess Shale (Alberta, Canada) contains very unique middle Cambrian fossils. n These animals displayed rapid diversification and existed for only a short period before they became extinct. Charles Dolittle Walcott

10. Burgess Shale, Canada

11. Burgess Shale Fossils Wiwaxia Anomalocaris Marrella

12. Ottoia Leanchoilia

13. Ordovician (490 - 443 million years ago) n Most animals alive in the Ordovician were similar to those alive in the Cambrian. n Introduction of animals similar to squid. –Cephalopods

14. The Ordovician Sea Floor

15. Ordovician Fossils Cephalopods (Squids)

16. Ordovician Fossils Brachiopods

17. Ordovician Extinction n The Earth’s climate became much cooler in the middle Ordovician. –Glaciers covered much of the continents –Sea level dropped n Climate change, probably, was responsible for the Ordovician mass extinction. n 60% of marine organisms

18. Silurian (443 - 417 million years ago) n The Earth’s climate became stable and a bit warmer during the Silurian. n This allowed many new animals to appear for the first time. –Coral Reefs –First (Jawless) Fish –Land plants

19. Silurian Coral Reefs n What is coral? An invertebrate animal related to jellyfish. n Small marine animals that live in warm water. n They make a “skeleton” out of calcium carbonate and often live in large colonies (reefs)

20. Silurian Coral nHorn Coral –Horn shaped –Usually lived alone; non-reef forming –Extinct nPipe Coral –Honey-comb shape –Often formed reefs –Extinct

21. Silurian Fish (Ostracoderm) n Vertebrates n Thought to be related to fish with jaws and sharks. n Ate through a ‘sucker’ mouth.

22. Eurypterids n Extinct group of marine organisms. n Feeding appendages in the front. n Related to modern spiders and scorpions. n NYS State Fossil

23. Silurian Plants n Lived near shorelines and in shallow waters n Slowly ‘invaded’ the land area by spreading in from rivers and lakes Cooksonia

24. Devonian (417 - 345 million years ago) n The first appearances of real “trees” –Most vegetation was small plants –Tallest plants were only about 3 feet tall n First amphibians n First wingless insects n Marine life continued – Brachiopods, coral, echinoderms, and new fish

25. Devonian Organisms Tree Fossil Cockroach & Tarantula similar to Devonian Arthropods Early Amphibian Fossil

26. Devonian Trees n Most were shorter than 1 meter tall. n Ferns, horse tails, and seed plants were common. n The first forests were present.

27. Devonian Insects (Arthropods) n Arthropods are the most successful type of animal on the planet. n 6 - 9 million species in a typical forest today. Not Devonian fossils

28. Carboniferous (354 - 290 million years ago) n Subdivided into the Mississippian and Pennsylvanian. n Lots of swamps and coal formation. n First reptiles. –Major biological revolution - the hard shelled egg!

29. A Carboniferous Forrest

30. Carboniferous Plant Fossils

31. Carboniferous Reptile Fossils n Reptiles can live on land or in water, BUT... n Amniotic egg - has a shell that allows animals to reproduce on land. n Allows reptiles to move further onto land, away from water.

32. Permian (290 - 245 million years ago) n Last period of the Paleozoic n Ends with the largest mass extinction in the history of the planet –Mostly affected the animals in the oceans

33. Permian Reptile Fossils Dimetrodon

34. Permian Reptiles Dimetrodon Leanchoilia

35. End of the Paleozoic n Largest mass extinction in Earth’s history –90% - 95% of all marine species became extinct –Likely due to changes in the environment and competition for living space. –Colder climate = –Volcanic eruptions =