Sharks, Skates and Rays Class Chondrichthyes Cartilaginous fish = skeleton made of cartilage (Bony fish = class Osteichthyes)

Characteristics Lack joints So, what is their movement like? Lack a swim bladder (used for buoyancy by bony fish) Large liver What do livers contain? How does this help sharks?

Shark Skin Denticles (as opposed to bony fish scales) Build up the same way as the teeth they are changed continually as the shark grows. Denticles derive from the epidermis (unlike the scales on bony fishes)

Bony fishes do not normally change their scales like sharks, instead the scales grow and becomes larger as the fish gets older. Shark denticles differ between species.

Shark Teeth Shark teeth are derived from the epidermis (skin) unlike Bony fish teeth which are derived from bone. Shark teeth are continually replaced

Different Teeth for Different Methods of Feeding Serrated teeth for tearing Pointed teeth for grabbing Blunt teeth for smashing

Filter Feeders Largest Sharks (Basking and Whale) use Gill Rakers to filter (catch plankton)

Ampullae of Lorenzini Detect electricity given off by all animals

Counter Current System