2.  Domain: Eukarya  Kingdom: Animalia ▪ Phlym: Chordata ▪ Subphylum: Vertebrata  Class: Chondroichthyes—sharks rays and all relatives  Subclass: Holocephali—Chimareras  Subclass: Elasmobranchii—Sharks and Rays

3.  Class Chondrichthyes  Includes sharks, rays, skates, and sawfish  Jawed fish  Lack a swim bladder  Skeletons made of cartilage (not bone)

4.  Though sharks are constantly swimming, they actually manage to do so without using much energy at all.  How do they do it?  Cartilage is lighter than bone  Large, oily livers keep them buoyant  Their energy saving techniques make them successful hunters—they do not have to eat as much, leaving them more energy to strike prey, and allows them to be quick and inconspicuous

5.  The shape of a shark’s fin and a ray’s body act like wings and give them lift  It allows them to glide through the water easier

6.  Scales called denticles cover the body  They are very similar to shark teeth  Point towards the tail and reduces friction from water

7.  “Conveyor belt” teeth that swing into place when old teeth are lost or need to be replaced

8.  Heightened sense of smell  Lateral Lines—detect water motion and vibrations  Ampullae of Lorenzini detect electrical currents generated by muscles of animals (electroreception) Ampullae of Lorenzini

9.  Eggs are fertilized internally using the male’s claspers to transfer sperm from male to female sharks.  The claspers are paired copulatory organs found at the base of the pelvic fins.  Fertilized eggs are produced and…  Some are released into the water  Others hatch in the mother’s body and they give live birth

10.  Oviparous—Species that lay eggs that mature and hatch outside of the body like birds  Viviparous—Give birth to live young  Ovoviviparous—Sharks have eggs that hatch and develop within the mother’s body (so she give produces eggs, but give birth to live young.  **Intrauterine Cannibalism** Some baby sharks eat all of their brother and sisters in the womb so that only 1 baby shark is born.

11.  Sharks are animals that mature later and produce fewer offspring  Therefore populations are easily affected by hunting

12.  The family Lamnidae = most dangerous predators of all of the chrondroichthyes  Include mako sharks and great white sharks  Incite fear into humans and are therefore killed without limit— making humans the most dangerous predators in the ocean.

13.  On average there are fewer than 10 fatal shark attacks a year  However, tens of thousands of sharks are killed each year  Sharks don’t kill any more than bees, mountain lions, and tigers  But if they do… But if they do…

15.  Whale shark (46 feet)  Basking shark (33 feet)  Megamouth shark (20 feet)  AND ALL ARE FILTER FEEDERS!

16.  Manta Ray (26 feet)  FILTER FEEDER AS WELL!