Sharks and Rays BY: SHELDON BROOKINS ITZEL LARA ROBERTO RAMIREZ

CHARACTERISTICS Are one of the most supreme predators throughout the globe. These two organisms are classified in class Chondrichthyes. There are over a 1,000 species or so of sharks, rays, and their close relatives in class Chondrichthyes. Don’t look the same on the outside, but they share a basic anatomy. They’re all jawed fished that lack a swim bladder and have a cartilaginous skeletons. In the Subclass of Elasmobranchii, which separates the sharks and rays from their relatives, the chimaeras. Chimaeras differ from Elasmobranches by having a relatively large head but no scales.

SPECIAL ATTRIBUTES Sharks and Rays don’t have to feed as much as other organisms the same size, by saving energy. They use less energy as they hunt, so they have ample energy to strike when they find their prey. Using less energy helps make them quicker and inconspicuous. Sharks have a “conveyor belt” of multiple rows of teeth that are constantly growing and swinging into place as the older teeth fall out. In both sharks and rays, scales called denticles point backwards. The denticles trap a film of water close to the organism’s body.

Sharks and rays store urea and other chemicals in their tissues so the water density matches the water density outside their tissues. Sharks have a sense of smell that detects incredibly diluted substances, such as blood from a wounded fish. Both sharks and rays have lateral lines (as do bony fish). Lateral lines are lines of sensory pores along the length of the body that detect water motion. The lateral line allows fish to detect vibrations of an approaching predator or, in the case of sharks and rays, struggling prey. CONTINUED

A few shark species re ovoviviparous, which means that the eggs hatch and the babies mature within the mother’s body. The female gives birth to live young rather than egg cases. This differs from mammalian live birth because the process involves eggs that hatch internally. Because sharks reproduce later in life and in smaller numbers than bony fish, some types of commercial fishing may be taking them from the ocean faster than they can breed. The whale shark is the largest fish in the ocean. They’re filter feeders that consume plankton. CONTINUED

ELECTRORECEPTION The ability to sense the small electrical currents on organisms that are created by muscles and nerves. Sharks and rays both have an organ called the Ampullae of Lorenzini. That enables them to send electrical currents on organisms. They use it to either find prey on the bottom of the ocean or murky waters.

SPECIAL ATTRIBUTES OF RAYS Literally fly through the water with their "wings". Use their "wings” for lift and motion, which leaves their tail free, unlike fish which need it for propulsion. Instead their tails contain poison which they use to defend themselves. Manta ray largest of all rays has a wing span of 26ft and just like the largest shark it feeds on plankton