1. Chondrichthyes
Cartilaginous Fish

2. Characteristics Endoskeleton entirely cartilaginous Fusiform Body
Mouth Ventral
Skin with placoid scales
2 chambered heart
Separate exposed gill slits
No operculum
Heterocercal tail
Internal reproduction (claspers & cloaca)

3. Characteristics con’t
No swimbladder or lung
2 olfactory lobes
2 cerebral hemispheres
2 optic lobes
1 cerebellum
1 medulla oblongata
3 pairs of semicircular canals
Ampullary organs of Lorenzini

4. Fusiform body Torpedo shape
Sharks have countershading (Dark on top & light on the bottom)

5. Placoid Scales
These scales point towards the tail and helps to reduce friction from surrounding water when the shark swims

10. Shark Anatomy

11. Shark Anatomy

16. Shark Senses
smell    hearing    lateral line organ     vision     ampullae of Lorenzini     touch and taste 

17. Tapetum lucidum
Reflects light in the eye

18. How a Shark Eats

19. Two chambered heart

20. Gill Slits

21. Lack operculum

22. Heterocercal vs Homocercal
Sharks have heterocercal caudal fins with the vertebrae extending into the superior region of the caudal fin

24. Shark Reproduction
Male claspers are inserted into female cloaca for internal fertilization
Ovoviviparous 90%
Viviparous (Great whites)
Oviparous

25. Chondrichthyes Reproduction
oviparous (laying eggs that hatch outside the mother's body)
ovoviviparous (brooding eggs that hatch within the mother's body, and then releasing the young)
viviparous (young develop within a uterus inside the mother's body, and are nourished prior to birth via a connection with the mother's bloodstream (placenta).

26. Female Reproductive Anatomy

27. Male Reproductive Anatomy

28. Cat Shark Egg
Oviparous
Porbeagle embryo viviparous
Dogfish Shark embryos
Ovoviviparous

30. Swimbladder Sharks lack a swimbladder
Oil in the liver is used to change buoyancy

39. Lateral Line System

40. Whale Shark
Worlds largest fish
(46 ft long)

41. Not many fossils
Guitarfish
(One of the few chondricthyes fossils)

42. Elasmobranchii
Includes the familiar sharks, skates, and rays, as well as some strange fossil relatives.
Elasmobranchs have an upper jaw that is not fused to the braincase and separate slit-like gill openings.

43. Rays & Skates

46. Rays & Skates
Rays and Skates, unlike sharks, are not fusiform, but dorsoventrally flattened.
Gill slits open on the ventral surface of the head
Spiracles on the top of the head direct water over the gills, to prevent sludge from clogging these delicate structures
They feed primarily on mollusks and crustaceans, and so have teeth modified for crushing.

47. Skates vs Rays
The major difference between skates and rays is the way in which they reproduce.
Rays are viviparous (live bearing)
Skates are oviparous (egg laying), releasing their eggs in rectangular cases sometimes called "mermaid´s purses".

48. Mermaid purse

51. Bradyodonti
Includes forms with an upper jaw fused to the braincase and a flap of skin, the operculum, covering the gill slits.
The Bradyodonti includes the chimaeras and ratfish, which are relatively rare, deep-water, mollusc-eating forms.

52. Chimaera

53. Ratfish