Sharks and Rays: Class Chondrichthyes

Life Science - Middle School

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Sharks & Rays - Class Chondrichthyes Sharks, rays and skates are in the Class Chondrichthyes or Cartilaginous Fish. Their entire skeleton is made of cartilage, which is softer than bone. This is different than the hard skeletons of Bony Fish, like tuna or trout. Cartilaginous fish have very hard teeth. Sharks need big, sharp teeth for tearing up large prey, while rays have hard, blunt teeth that crush the shells of their prey (clams, snails and crabs). Cartilaginous fish are all cold-blooded vertebrates. They breathe through gills and have paired nostrils which pick up the scent of prey by detecting blood in the water from a long distance. They have at least two pairs of fins, one pair in front (pectoral fins) and one pair in back. Sharks are famous for their large dorsal fin seen above the water as they swim along the surface. Rays and skates mostly have large flattened, pectoral fins that look like wings and are attached to the head in the front. The skin of sharks and rays is covered with tiny scale-like teeth, which make it rough like sandpaper, and very tough. Sharks have survived millions of years by adapting to many ocean habitats, from the arctic Greenland shark (1) to the many species prowling the tropics and temperate water, including the blue shark (2), hammerhead (3), tiger shark (4), whale shark (5), great white shark (6), and thresher shark (7). Rays, like the southern sting ray (8) are mainly found in warmer tropical waters. The Class Chondrichthyes is broken down into about ten groups or Orders which make up 45 very diverse families, from tiny lanternfish to the massive whale shark. 4 1 3 5 8 6 7 2
94-4029 Sharks, rays and skates are in the Class Chondrichthyes. Their entire skeleton is made of _________________________, which is softer than bone. Their teeth are very hard. Sharks need big, sharp teeth for tearing up large prey, while rays have hard, blunt teeth that crush the ____________________ of their prey (clams, snails and crabs). Cartilaginous fish are all ___________________________________ vertebrates. They breathe through ____________ and have paired nostrils which pick up the scent of prey by detecting blood in the water from a long distance. They have at least two pairs of ______________, one pair in front (pectoral fins) and one pair in back. Sharks have survived millions of years by adapting to many ocean habitats, from the arctic Greenland shark (1) to the many species prowling the tropics and temperate water, including the blue shark (2), ____________________________ (3), tiger shark (4), ________________________ shark (5), _________________ ___________________ shark (6), and thresher shark (7). Rays, like the southern ____________________ ray (8) are mainly found in warmer tropical waters. 4 1 3 5 8 6 7 2 Sharks & Rays - Class Chondrichthyes