1. Earth History GEOL 2110 The Paleozoic Era Silurian and Devonian Periods - Part I Time of Fish, Amphibians and Forests

2. Major Concepts Biodiversity on the seafloor continued in Silurian and Devonian times. Ammonites replaced Nautiloids; Bony fish diversified to skeletal fish. Land began to be populated with burrowing animals, spiders, scorpions and later amphibians Spore-bearing vascular plants took root in the form of club moss, ferns, horsetails and seed ferns. The proliferation of coral reefs caused restricted basins wherein great thickness of limestone and evaporites were deposited.

3. Silurian – Devonian Major Events

4. Marine Biodiversity Recovers from Ordovician Extinction Spirifer Brachiopods Thick-walled, “winged” Brachs 1’ Trilobites get big and defensive

5. Marine Biodiversity Recovers from Ordovician Extinction Coiled Ammonoid Cephalopods Replace Straight Nautiloids

6. The Age of Fishes Jawed Spiny Acanthodians

7. Invasion of the Land Spore-bearing Vascular Plants take Root Rhynia – leaf-less tubes Psilophyton –Rooted, strong bundled stalks Lycopsids (Club Moss) Sphenopsids (Horsetail) Vascular stalks transfer water and nutrients throughout the plant

8. Plants colonize the land! Invasion of the Land Late Devonian – Seeded Plants and Trees Fossilized Seeds from a Seed Fern Modern-day seeded tree fern as existed in the Late Devonian Late Devonian Seed Fern Stumps, Catskill Mtns, NY Seed are better than spores at retaining moisture and are more easily fertilized

9. Plants colonize the land! Invasion of the Land Vascular Plants take Root

10. Plants colonize the land! Invasion of the Land Bugs and Slimy Creatures Follow Devonian centipede claw and head Devonian compound insect eye Millipede fossil

11. Plants colonize the land! Invasion of the Land Bugs and Slimy Creatures Follow

12. Proliferation of Reefs

13. Huge reefs in the Silurian and Devonian, made of: Sponges Rugose Corals Tabulate Chain Coral Heliophyllum Hexagoneria Silurian-Devonian Coral Reefs

15. Ecological Zonation of Coral Reefs

16. Reef Facies Devonian Reef Complex, W. Australia

17. Modern-day Reef Environment

18. Silurian Reef Thorton Quarry, South of Chicago

19. Late Devonian Extinction Another Cool Down?

20. Next Lecture The Paleozoic Era Silurian and Devonian Periods – Part II Stratigraphy and Tectonics