1. Sharks

2. Class Chondrichthyes • skeletons made up entirely of cartilage • cartilage contains thousands of minute prisms containing mineral that strengthens bones (hydroxyapatite) • distinctive teeth, highly resistant to decay

3. Order Carcharhiniformes • “Ground Sharks” • nictitating eyelids present • mouth behind front of eyes • five pairs of gill slits • anal fin present

4. Family Carcharhinidae • head “normal” without lateral expansions • first dorsal fin originates in front of pelvic fins • anal fin trailing margin strongly concave

5. Tiger Shark (Galeocerdocuvier) • snout very short, bluntly squared-off • upper lobe of caudal fin very long, sharply pointed • pigmentation pattern: dark spots/vertical bars on back and flanks

6. Tiger Shark (Galeocerdocuvier) • electromagnetic receptors, Ampullae of Lorenzini • lateral line reads vibrations in water, movement of animals nearby • 2nd most attacks on humans, behind great white

8. Family Sphyrnidae • head with lateral, canard-like extensions • pelvic fins triangular

9. Scalloped Hammerhead (Sphyrnalewini) • head,hammer-narrow and broadly arched with prominent indentations at each nare and the midline • pelvic fins triangular • first dorsal fin origin over or slightly behind pectoral axil

10. Scalloped Hammerhead (Sphyrnalewini) • tends to form huge schools • hammer enhances senses of smell, electroreception, lift and maneuverability • prevents 3D vision and jaw protrusion