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Phanerozoic [Paleozoic cont...] (25)
Fichas del conjunto (14)
- 1In general, are Ordovician fossils similar to or different from Cambrian fossils?Different
- 2☼What changes are there between the Cambrian fossil record & the Ordovician fossil record?☼-Biodiversity has tripled
- 3☼What feeding style is dominant in the Ordovician?☼There is an increase in filter feeders
- 4Are trilobites dominant in the Ordovician?There are fewer trilobites
- 5What organisms are most common in the Ordovician?Brachiopods & Bryozoans
- 6What other organisms are common in the Ordovician record?-Corals & crinoids
-Nautiloids, clams, snails - 7☼What kind of fish appeared in the Ordovician?☼Jawless fish
-Have no jaw, but have mouth.
-Fist fish had no jaw - 8What kinds of organisms were up on the land during the Ordovician?Cryptobiotic crusts (fungi, bacteria, algae)
- 9☼When did the first land plants appear? What's the evidence?☼-Late Ordovician
-Root traces in paleosols and microfossils of spores - 10What is the Beecher’s Bed Lagerstatte?-Upper Ordovician
-In New York State, USA
-Marine dark shales
-Pyritized fossils, included appendages - 11Were there any mass extinctions during Cambrian?- 5 Small mass extinctions
- 12Who were the victims of the Cambrian extinctions?Trilobites
- 13☼What is the end-Ordovician mass extinction?☼~85% of marine spp. gone
-2nd worst mass extinction ever - 14☼What are the known and proposed causative mechanisms of the end-Ordovician mass extinction?☼-Caused by glaciation in Gondwana
-Short, severe Ice Age in Africa
-Caused a Regression
-(speculation) Gamma ray burst & ozon destruction & increase in ultraviolet solar radiation > kills photosynthesizers & food web collapes
-Moss
-Cooling form CO2 drawdown