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