Sharks

Throughout time cheats halt been deemed man-eaters or dangerous animals . until now , there be over 365 species of sharks and only a shove few present inflicted fatal , malicious human attacks : tiger , great white bull , and white-tip oceanic sharks . Although sharks argon grand and powerful creatures , they are also very curious and umteen attacks are they result of an exploratory bite belong to the disunite Chondrichthyes elasmobranchii and are tilt , but different fish have a completely cartilaginous skeleton that is aerial and flexible (Hamlett , 1999 . The body is covered with small outgrowths called denticles . These denticles are incredibly rough and are similar in grammatical construction to their teeth . Studies have found that denticles create vortices that reduce charm as the shark floats to become m ore efficient (Hamlett , 1999Caudal fins of sharks divert betwixt species . The tail provides speed and acceleration is depended on the caudal construct . For example , the tiger shark s large focal ratio lobe gives upper limit power and sudden busts of speed (Nelson , 1994 . An bonny shark impart cruise at five miles per moment yet when contend prey , can reach speeds of 12 mile per hour . The short fin mako shark is considered to be the winged shark reaching speeds over 30 miles per hour (Martin , 2006 . track adaptations have otherwise purposes than speed . The cookie cutter shark has great lobes that are luminescent , which are believed to entice prey towards the shark (Nelson , 1994These creatures respire by extracting oxygen from the seawater purlieu and deteriorate it over the gills . Due to the shark s large sizing galore(postnominal) require a higher supply of oxygen than other fish and must be continually travelming in to meet the demands or the shark w ill suffocate (Hamlett , 1999 . This bite ! is known as ram ventilation Fishes have gas-filled swim bladders - sharks do not . They have a large oil-filled colorful , which can compose up to 25 percent of the calculated weight unit , for buoyancy .

Nevertheless , their buoyancy is confine , and they will duck if swimming is halted (Compagno , et al , 2005 . It is also enunciate that if inverted , sharks take down what is called a natural state of tonic immobility . Researchers wont this as a in force(p) handling technique (Pratt , et al , 1990Carnivorous sharks do not have teeth at the mandibula , but embedded in the flesh that are forever replac ed throughout the shark s heart . have multiple conduct and bottom rows of teeth that are replaced every 10 long time to several months depending on the species . Teeth are in various shapes that serve many a(prenominal) purposes from gripping , cutting or suppression shellfish (Hamlett , 1999 have keen olfactory senses that can ferret out whiz part per million of blood in their environment . imprecate on the sharp sense of smell to take notation prey . Their sight is similar to vertebrates that consist of lenses , corneas , and retinas Hamlett , 1999 . eyesight is play off to dark waters with the help of a specialized attract called the tapetum lucidium , which reflects light back to the retina allowing them to see in...If you want to get a full essay, order it on our website: OrderCustomPaper.com

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