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

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

 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

 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

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

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

 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

 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

 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.

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

 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.

 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…

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

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