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 asEITHER A) hard copy, B) HTML download, or C) PDF
1. Based on the graph, explain how catch continues to increase through timewhile 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?
Major evolutionary events in Vertebrate History
1) Evolution of jaws and paired appendages
2) The Evolution of Tetrapods and Invasion of Terrestrial Environments
Devonian Age of Fishes- Ostracoderms, placoderms, acanthodians, chondrichthyes, actinopterygians, sarcopterygians, first tetrapods!!
Devonian conditions
Warm shallow seas
Land with primitive plants
Land with terrestrial invertebrates
Why important?
Lots of aquaticDevonian predators and competitors
So what?
Hypotheses about evolutionary forces driving invasion of the land include:
Important fossil forms in the evolution of vertebrates
Coelocanths Lungfish
Osteolepiforms+ Amphibians Amniotes
See Figure 9-2
Acanthostega+
Ichthyostega+P*
* Panderichthyes
Osteolepiforms & Panderichthyes = sarcopterygian fishAcanthostega & Ichthyostega = “stem tetrapods”
Panderichthyes
Osteolepiform
Fig 9-3
Osteolepiform fish
Ichthyostega
Acanthostega
Evolution of Tetrapods – wonderful example of transitional forms
Fig 9-3 & 9-7
Osteolepiform
Acanthostega
Ichthyostega
Challenges of Terrestrial Life:
Respiration via lungs
Obtaining food
Support
Respiration - Breathing in Lungfish
Feeding on Land Catching and swallowing prey
Suction feeding
Freeing the forelimb from the head Fig 8-6
Muscular tongue - a tetrapod innovation!
Moving onto land – “I’m so heavy!” Fig 8-3 Vertebrae, limbs, girdles
Attaching limb girdlesTo vertebral column
Muscular attachmentOf flat girdle
Bony attachment via sacrum and ilium of pelvis
Evolution of the tetrapod limb - Trying to Find Fingers in Fins Fig 9-5
Osteolepiform Dipnoan
Only tetrapods
thumb
“pinky”
Note major shifts in Tetrapods Fig 8-4
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