Unit 2: Fish, Amphibians, Reptiles

1. Unit 2: Fish, Amphibians, Reptiles 8 days

2. September 10th: Chordata and Vertebrata • Chordates are animals that have internal notochords. • Most are vertebrates, but a few are invertebrates • The 2 types of invertebrate chordates are the lancelets and tunicates

3. General Characteristics • Marine • Called Urochordates • Lancelets superficially resemble fish • Tunicates superficially resemble sponges

4. Lancelet Anatomy

5. Tunicate Anatomy

6. Classification Kingdom: Animal Phylum: Chordata Class: Ascidiacea Sea Squirts: ~2,000 sp Attached to coastal rocks and the sea bed Bag-like tunicates Some predatory, most filter feeders Often colonial Larva resemble tadpoles

7. Classification Kingdom: Animal Phylum: Chordata Class: Thaliacea Pelagic Tunicates: ~70 sp Planktonic in ocean Large perforated pharynx, used for filter feeding Individuals up to 10in and colonies up to 46ft

8. Classification Kingdom: Animal Phylum: Chordata Class: Leptocardia Lancelets: ~24 sp Shallow sand or gravel Tropical or temperate Sexual External fertilization

9. Vertebrates • What is a vertebrate? • Less than 3% of animals are vertebrates

10. General Characteristics • Subphylum: Vertebrata • ~64,000 sp • Vertebral column • Gills • CNS

11. Classification Kingdom: Animal Phylum: Chordata Subphylum: Vertebrata Class: Mammalia Class: Aves Class: Reptilia Class: Amphibia Class: Myxini (Hagfish) Class: Cephalaspidomorphi (Lampreys) Class: Chondrichthyes (Cartilaginous Fish) Class: Osteichthyes (Bony Fish)

12. September 11th and 15th: Fish • What are fish? • Informal collection of diverse animals • 4 classes

13. General Characteristics • Largest group of vertebrates • Has gills • Has scales • Ectothermic (Cold-blooded) • Maneuvers using fins (median and/or paired)

14. General Characteristics • Internal skeleton (material varies) • Vision varies • Hearing typically good, utilize swim bladder • Taste and smell often linked • Lateral line system, pressure

15. General Characteristics • Some can detect electrical signals: • Cartilagionous fish receive impulses by structures called the ampullae of Lorenzini • Located in pores at surface of skin • Contain a conductive gel • Some species can produce electrical currents

16. Evolution • First appeared more than 500 mya • Originally jawless • Jaws eventually evolved from front gill arches • Cartilaginous fishes appeared around 370 mya • Typically have 2 chambered heart

17. Fish Anatomy

18. Types of Scales

19. Gill Physiology

20. Lungfish • Can breathe air using primitive lung-like organs:

21. Oxygen Diffusion • Some fish can diffuse oxygen and CO2 through their skin:

22. Marine vs. Freshwater • Salt concentration is different inside the fish vs. outside environment: • Marine need to keep water in • Freshwater need to keep water out • Osmosis

23. Marine vs. Freshwater • Salmon, lampreys, sharks, and rays • Same concentration inside and out • Able to transfer salt in and out of their bodies

24. Temperature Control • Seek sun and/or shade • Alter pigments • Change depth • Blood contains antifreeze-like protein (Icefish) • Conserve heat generated by large swimming muscles (GW shark, tuna, etc.)

25. Reproduction • Sexual • Usually external fertilization • Timing is varied • Location is varied • Sperm = milt; eggs = roe

26. Parental Care • None • Nest guarding • Mouthbrooding • Ex. Sea Horses

27. Class: Myxini and Cephalaspidomorphi • What are jawless fishes? • ~90 sp

28. General Characteristics • Elongated bodies • Smooth, scaleless skin • Jawless mouth • Varied habitats • Can be parasitic

29. Lamprey Anatomy • Moderate vision • Breed in freshwater, adults typically marine • Pass through several larval stages

30. Hagfish Anatomy Can secrete slime Totally marine Virtually blind No larval stages

31. Class: Chondrichthyes • What are cartilaginous fish? • ~810 sp • Sharks, skates, rays

32. General Characteristics • Skeleton made from cartilage • Specialized teeth, replaced continuously • Skin covered in toothlike scales • Mostly marine

33. General Characteristics • No swim bladder • Carnivorous • Oil-rich liver increases buoyancy • Mostly negatively buoyant, much keep swimming

34. General Characteristics • All have ampullae of Lorenzini • Most have lateral line systems • Good sense of smell • Internal fertilization

35. Reproduction • 3 process of producing young: • Release leathery egg cases (mermaid pouches) • Young hatch from egg inside female’s body • Young develop inside a placentalike structure No larval stage

36. Sharks • Frilled Shark: ovoviviparous, 6.5ft • Spotted Wobbegong: viviparous, 6ft

37. Sharks • Basking Shark: ovoviviparous, 33ft • Tiger Shark: ovoviviparous, 20ft

38. Sharks • Bull Shark: viviparous, 11ft • Shortfin Mako: ovoviviparous, 13ft

39. Sharks • Whale Shark: viviparous, 39ft • Great White Shark: viviparous, 20ft

40. Skates and Rays • Smalltooth Sawfish: viviparous, 20ft • Manta Ray: viviparous, 20ft

41. Skates and Rays • Eagle Ray: viviparous, 8.5ft • Blue-spotted Stingray: viviparous, 6.5ft

42. Class: Osteichthyes • What is a bony fish? • ~23,500 sp • 2 subclasses: Lobe finned and Ray finned

43. General Characteristics • Skeleton made from bone • Most have swim bladder • Varied aquatic habitats • Often good vision and hearing

44. General Characteristics • Typically external fertilization • Some hermaphroditic species • Both sequential and simultaneous • Schooling • Most pass through larval phases

45. Subclass: Sarcopterygii Lobe-finned fishes:

46. Lobe Fin Anatomy

47. Coelacanth • Thought extinct for 65 million years

48. Subclass: Actinopterygii Ray-finned fishes:

50. Ray-finned Fishes • European Sturgeon: 11ft • Snipe Eel: 30in