1. Form and Function: Fish (begin) Marine Vertebrates: Lecture 1

2. Challenges of the marine environment Density Pressure Temperature

3. Temperature stratification

4. Challenges of the marine environment Density Pressure Temperature Light

5. Light attenuation with depth

6. Challenges of the marine environment Density Pressure Temperature Light Salinity Oxygen

7. Oxygen vs. depth

8. Challenges of the marine environment Density Pressure Temperature Light Salinity Oxygen Seasonality Substrate

9. Vertebrate phylogeny Vertebrates are thought to be monophyletic, descended from a cephalochordate (or urochordate?) ancestor  So ultimately, all marine vertebrates are related However, the “marine vertebrates” themselves are polyphyletic, with various groups arising from fresh water or land-based ancestors at different times.

10. Fish phylogeny

11. Likely common ancestor to vertebrates: Phylum Chordata Subphylum Cephalochordata Invertebrate chordate = “lancelet” Larvae and adults have all chordate features (four shown plus endostyle = thyroid precursor) Muscles develop from somites: blocks of mesoderm (segmented)

12. Subphylum Cephalochordata: lancelets

13. Fish phylogeny: “Craniata” Derived character: neural crest cells/cranium Neural crest/ cranium

14. Neural crest (Craniata)

15. Phylum Chordata, Subphylum Myxini: Hagfish Campbell, Fig. 34.9

16. Fish phylogeny: Phylum Chordata, Subphylum Vertebrata Derived character: vertebral column Vertebral column

17. Subphylum Vertebrata; Class Cephalaspidomorphi

18. Fish phylogeny: Phylum Chordata, Subphylum Vertebrata, “Gnathostomes” Derived characters: jaws, bone, paired fins Jaws; Bone; Paired fins

19. Gnathostomes Jaw development  From which structures? Development of bone  Which structures were first mineralized? Development of paired fins  Hypothesis for origins?

20. Class Chondrichthyes: Subclass Elasmobranchii

21. Elasmobranchii: Features Skeleton  Vertebral column  Cranium  Teeth  Upper jaw  Ceratotrichia Nostrils

22. Elasmobranchii: Features Spiral valve within intestine: Function? Pelvic fins with claspers. Function?

23. Elasmobranchii: Features Gills Scales: placoid Buoyancy Australian Museum of Natural History

24. Circulation Campbell, Biology

25. Respiration: countercurrent exchange Campbell, Biology

26. Additional features Osmoregulation Reproduction  Oviparity  Ovoviviparity  Viviparity

27. Feeding

28. Shark Orders

29. Order Lamniformes: mackerel sharks Overview

30. Focus: Family Lamnidae Adaptations for effective swimming  Body shape (note snout!)  Fins  Ram ventilation  Cruising speeds: ~3 km/h (great white)  Speed bursts: Up to 35 km/h (mako)  Elevate body temperature Countercurrent heat exchange

31. Countercurrent heat exchange: Great white shark

32. The Behavior of White Sharks and their Pinniped Prey during predatory attacks Summary of research by Klimley, Pyle and Anderson, 1996 (for next Monday!) Deskpicture.com

33. Order Lamniformes Focus: basking sharks Photos: D. Burton

34. Order Charcharhiniformes Groundsharks: Overview Photo: Paul Humann Photo: Guillaume Chanfreau

35. Order Charcharhiniformes Focus: Hammerheads Photo: Guillaume Chanfreau

36. Order Charcharhiniformes Focus: reef sharks (requim)

37. Order Orectolobiformes Carpetsharks: Overview

38. Order Orectolobiformes Focus: Wobbegongs

39. Order Orectolobiformes Focus: Nurse sharks Photos: Paul Humann

40. Order Orectolobiformes Focus: Whale sharks Photo: Werner Mischler

41. Order Heterodontiformes Bullhead sharks Horn shark Photo: Tom Campbell, Innerspace VIsions

42. Order Hexanchiformes Photos: Michigan Science Art Frill shark Bluntnose sevengill shark

43. Order Squaliformes Dogfish sharks Spiny dogfish Photo: J. Stafford-Deitsch

44. Order Squaliformes Cookie-cutter shark

45. Order Pristiophoriformes sawsharks

46. Order Squatiniformes Angel sharks

47. Skates and rays Overview Photos: Paul Humann

48. Order Rajiformes: skates

49. Order Torpediniformes electric rays

50. Order Myliobatiformes bat rays, stingrays, manta rays Photo: Andy Murch Photo: Paul Humann

51. Class Chondricthyes Subclass Holocephali