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Scientific articles for Friday oral reports: 1)Must be from peer-reviewed journal, not website 2)Must get access to entire article, not just abstract as EITHER A) hard copy, B) HTML download, or C) PDF
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1.Based on the graph, explain how catch continues to increase through time while per capita catch does not 1.What is “bycatch”? 2.What are the ecological effects of overfishing? 3.Where does the coelocanth occur? 4.Can you drown an Australian lungfish by holding its head under water? 5. What evolutionary events had already occurred by the Devonian that were critical for the evolution of the tetrapods?
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Major evolutionary events in Vertebrate History 1)Evolution of jaws and paired appendages 2) The Evolution of Tetrapods and Invasion of Terrestrial Environments
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Devonian Age of Fishes- Ostracoderms, placoderms, acanthodians, chondrichthyes, actinopterygians, sarcopterygians, first tetrapods!!
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Devonian conditions Warm shallow seas Land with primitive plants Land with terrestrial invertebrates Why important?
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Lots of aquatic Devonian predators and competitors So what? Hypotheses about evolutionary forces driving invasion of the land include:
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Important fossil forms in the evolution of vertebrates Coelocanths Lungfish Osteolepiforms+ AmphibiansAmniotes See Figure 9-2 Acanthostega+ Ichthyostega+ P* * Panderichthyes Osteolepiforms & Panderichthyes = sarcopterygian fish Acanthostega & Ichthyostega = “stem tetrapods”
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Panderichthyes Osteolepiform Fig 9-3
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Osteolepiform fish Ichthyostega Acanthostega Evolution of Tetrapods – wonderful example of transitional forms
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Fig 9-3 & 9-7 Osteolepiform Acanthostega Ichthyostega
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Challenges of Terrestrial Life: Respiration via lungs Obtaining food Support
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Respiration - Breathing in Lungfish
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Feeding on Land Catching and swallowing prey Suction feeding
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Freeing the forelimb from the head Fig 8-6
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Muscular tongue - a tetrapod innovation!
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Moving onto land – “I’m so heavy!” Fig 8-3 Vertebrae, limbs, girdles
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Attaching limb girdles To vertebral column Muscular attachment Of flat girdle Bony attachment via sacrum and ilium of pelvis
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Evolution of the tetrapod limb - Trying to Find Fingers in Fins Fig 9-5 OsteolepiformDipnoan Only tetrapods thumb “pinky”
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Note major shifts in Tetrapods Fig 8-4
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