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SHARKS PowerPoint Presentation

SHARKS

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SHARKS

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  1. SHARKS

  2. SHARKS Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class Chondrichthyes 8 Orders 30 Families ~350 Species

  3. SHARKS • first appeared ~ 450 my ago

  4. SHARKS Iniopteryx ~375 my Belantsea ~350 my Helicoprion ~345 my Ischyodus ~150 my Stethacantus ~375 my

  5. SHARKS • first appeared ~ 450 my ago • “modern” forms ~ 300 my • many early forms became extinct w/ dinosaurs; others evolved coincident w/ rise of mammals (white shark 60-65my) • Carcharodon megalodon 50-35 my – teeth 10in; length 40’

  6. SHARKS • Of ~ 350 extant species: • 82% < 2 meters • 50% < 1 meter • Avg. max length 1.5 m • only 4% > 4 m

  7. angel sharks sawtooth sharks dogfish sharks cow sharks Family Carcharhinidae (Requiem) – 48 species: tiger, blue, bull , reef Family Lamnidae – (mackeral) white, mako, sand tiger, basking whale shark, nurse hammerhead, bullhead

  8. SHARKS Shark senses: • eyes – similar to most vertebrates, size varies w/ habitat; retinas more rod cells (dim light), fewer cone cells (bright light); tapetum (tapetal plates); nictitating membranes • ears – great accoustic sensitivity; sharks: 10-800Hz (struggling fish), humans: 25-1600Hz • lateral lines - >6,000 pits, grooves, canals lined w/ cilia – sensitive to low freq. pressure waves • nasal sacs – some sharks 80% of brain devoted to smell • Ampuli of Lorenzini • teeth

  9. SHARKS Great White Sand tiger Sand tiger placoids (dermal denticles) Tiger

  10. SHARKS Sharks may shed as many as 30,000 teeth in a lifetime!

  11. SHARKS Why do sharks attack humans? • mistaken identity?

  12. SHARKS Why do sharks attack humans? • mistaken identity? • test bites? • territoriality? • hungry?

  13. SHARKS Some shark factoids: • more humans are killed by dogs in the US each year than have been killed by sharks in US waters in the last 100 years • 20 Great White sharks die in fishing nets off CA each year; 0.13 humans are killed by Great Whites • more people are killed by hogs in Indiana than by sharks in the US • worldwide, about 3 times as many people are killed by elephants than sharks • You are: 6,527X more likely to die on the highway, 235X more likely to be killed by lightning, 37.5X more likely to die by snake bite than being killed by a shark

  14. SHARKS Some shark factoids: • You are more likely to be killed by a falling TV than being killed by a shark • You are 130X more likely to be killed by a deer than by sharks • More people are killed each year by electric toasters than by sharks • More people die by being buried in beach sand each year than are killed by sharks • 6X more people are killed by ATV accidents in the US each year (600)than have ever been killed by sharks in all of US history • More people are seriously injured in ATV accidents each year (125,000) than have ever been injured by sharks worldwide in recorded history

  15. SHARKS Humans kill more than 100,000,000 sharks per year, many just for their fins So who is the more dangerous predator?