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Alleghanian orogeny
Pennsylvanian- Modern day US and Africa (Gondwonaland) collide to form Pangaea
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Acadian orogeny
Silurian/Devonian - collision of Baltica and Avalonia
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Taconic orogeny
- Ordovician - Island arc collides with Laurentia (Modern N. Am) on the eastern margin
- forms the Appalachian mountains
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Cambrian macrofauna
- poorly calcified marine invertebrates (Trilobites)
- inarticulated brachiopods, primitive crinoids
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Paleozoic macrofauna
well calcified invertebrates, articulated brachiopods, crinoids, rugose+tabulate corals - development of reef communities
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Modern macrofauna
- taxa that survive the Permo-Triassic extinction
- eg. gastropods, bivalves
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Permo-Triassic extinction
90 to 95 of all species extinct - trilobites, tabulate corals and rugose corals die out, death of reef life
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Causes of Permo-Triassic extinction
- weak evidence for meteorite theory - A huge volcanic episodes released gases - Siberian Traps-evidence of changes in carbon and sulfur cycle
- or - gases trapped in massive glaciers, released by melting - evidence...death of passive breathers
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Best dating method for materials under 60,000
- Carbon 14 dating
- uranium lead dating for oldest materials,
- potassium argon
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Importance of the Burgess Shale
Cambrian explosion-Shows great diversity in body types, unique phyla...basis for Gould's model of diversification and decimation - First appearance of hard bodies, important for fossil record
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Anagenesis vs. cladogenesis
- Anagenesis is variation with in a species
- Cladogenesis is a division of the species (speciation)
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