1. sharks, skates, rays shark rayskate shark

2. 460+ species Streamlined body Cartilaginous skeleton Oil in Liver Must swim continuously Sharks

3. Sharks have a head, a middle called a trunk, and a tail.

4. water enters spiracles caudal fin … and exits through 5 to 7 pairs of gill slits heterocercal tail teeth are shed and replaced

5. Different kinds of sharks have different kinds of tails.

6. Predators with teeth!

9. Hammerheads are aggressive hunters, feeding on smaller fish, octopuses, squid, and crustaceans. They do not actively seek out human prey, but are very defensive and will attack when provoked.

10. Nurse sharks prefer to dwell near the sea floor in the warm, shallow waters of the western Atlantic and eastern Pacific oceans.

11. The mouthy basking shark is a filter-feeder. It is the second- largest shark, after the whale shark, reaching lengths up to 33 feet (10 meters).

13. Sharks’ teeth are modified placoid scales

14. … but the largest sharks filter plankton (free floating, mostly microscopic organisms) maximum length: 15.2 m but most <10 m

15. The whale shark filters plankton

17. How sharks (almost) achieve neutral buoyancy Cartilaginous skeleton (bone is dense) Pectoral fins, surface of the head and heterocercal tail provide lift Large livers with large quantities of lipids (sp. gr.= 0.90-0.92) and squalene (sp. gr. = 0.86). (Specific gravity of seawater = 1.026.) … but are still negatively buoyant and must swim continuously

18. Most sharks are viviparous!

19. oviparous – eggs laid outside the mother’s body ovoviviparous – mother retains eggs in uterus; embryo nourished by egg yolk; young born alive viviparous – embryos develop inviviparous the uterus nourished by the mother’s blood through a placenta

20. Direct development: a shark pup emerges from its egg.

21. Despite their rows of ragged teeth and vicious appearance, sand tiger sharks are actually rather docile, usually attacking humans only in self-defense.

22. Confirmed Unprovoked Shark Attacks Florida – 717 Fatal-11 Hawaii – 129 California – 114Fatal-10 South Carolina – 82Fatal-2 North Carolina – 52Fatal-3 Texas – 39Fatal-3 Oregon – 26 Delaware – 4 Maryland - 0 Total in USA from 1837-2014: 1,052 Source: Florida Museum of Natural HistoryFlorida Museum of Natural History

23. Skates and rays: cartilaginous fish collectively known as “batoids”

24. What is the difference between skates and rays? Rays are kite-shaped with streamlined tails

25. Skates have fleshy tails with small fins Clearnose Skate

26. Sting ray with spine (modified placoid scale) with venom gland at base.

27. skate

28. Manta ray: a plankton feeder 6 m

29. All skates lay eggs; rays are ovoviviparous! Mermaid’s purse (skates)

30. Rays fewer species long, thin tail without fins stingray tail armed with spines ovoviviparous Skates more species thicker tail with fins horns on tail oviparous