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Sharks. Classification. Kingdom Animalia Phylum _____________ Class _____________ Subclass _____________ Superorder _____________ Known as “__________” until the 16 th century Name “shark” may have come from the Yucatec Maya. Evolution. Earliest sharks evolved _________ years ago
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Classification • Kingdom Animalia • Phylum _____________ • Class _____________ • Subclass _____________ • Superorder _____________ • Known as “__________” until the 16th century • Name “shark” may have come from the Yucatec Maya
Evolution • Earliest sharks evolved _________ years ago • Today – _________ species • Smallest – dwarf lanternshark (7 in) • Largest – whale shark (largest fish – 40 ft)
Skeleton • No bones • Use cartilage and connective tissue • Strong , but ___ the __________ of bone • Reduces weight saves energy • Cartilage may be _____________ • “bone-like” • No functional _____________ • Must stay in water
Jaw • Covered in a layer of _____________ • Complex ________ surface • Single tile in a mosiac • Tiny hexagonal plates • Crystal blocks of _____________ • Most sharks have one layer of tesserae • Great white sharks – up to _____________
Teeth • Embedded into _____ rather than the jaw • Arranged into _____ rows of ______ teeth • Continuously replaced • Gums “_____________” them to the front • Can shed ____________ teeth in a lifetime • Tooth characteristics determined by _______ • Very important to fossil record – all that remains
Fins • Supported by unsegmented _____ composed of _____________
Tail (Caudal) Fins • ____ different designs found in sharks • Shapes evolved due to different _________ and _____________ • All are _____________ in design • Top is _______ than the bottom
Buoyancy • ____ swim bladder • Large _____________ • Up to _____ of body mass • Contain _____________ • Oil that is _____________ that water • Sharks hunted for this oil • Put in capsules as a health supplement • Used in vaccines • Also available from plant sources
Respiration • Oxygen removed as water passes through the mouth and over the _____________ • Process known as _____________ • Most sharks can pump water over their gills while at rest • Some cannot (obligate ram ventilators) • Gills _______ covered (as with most fish)
Circulation • Sharks have a ______ chambered heart
_________________ • Most sharks are _________________ (cold blooded) • Body temp is that of the environment • Family Lamnidae sharks can raise their body temp higher than the water temp (includes mako and great white) • _____________ • Strip of red muscle in center of body attached to the __________________ (miraculous net)
Rete Mirabile • Uses ___________________ flow design
_____________ • Living in salt water • Large production of _____ • Shark’s tissues ________________ (in balance with) the sea water • So, few sharks can live in fresh water • Bull sharks can change their kidney function to ____________________________
Senses – Smell • Very keen ________ sense • Can detect __________ of blood in sea water • Even greater attraction to chemicals found in _________ of organisms • Leads sharks to sewage outfalls
Senses – Sight • Eyes similar to most vertebrates • Well adapted to the dark marine environment • Use a _______________ (bright tapestry) • Reflects light back through the retina to increase amount of useable light • Humans do the same (_____________ in a photo) • Can _____________ and _____________ their pupils
Senses – Sight • Sharks have eyelids, but _____________ • Water cleanses eyes • Use __________________________ • _______________ that moves over eyes to protect them during ___________ on prey
Senses – Hearing • May be able to hear prey ____________ away • Hard to test • Small opening on each side of the head • Leads to the inner ear • Sense _________________ among the water molecules
Senses – Hearing • _____________ system • System of _________ within the lateral line • Runs the length of the body • ___________ expose water to the system • Contains ____________ cells with hair-like projections • Also helps with ________ and movement
Senses – _____________ • Sharks can detect electromagnetic fields produced by all living organisms • Sharks have the _____________ electrical sensitivity of any organism • Helps them find prey (even under the sand) • Use ____________________________ • Electrorecptor organs • Hundreds to thousands per shark
Senses – Electroreception • Ocean currents travel through the magnetic field of the earth • Creates electric fields • May allow sharks to _____________ the world’s oceans • Allows sharks to detect _____________ __________________