Sharks

Throughout time cheats have been deemed man-eaters or dangerous animals . even , there are over 365 species of sharks and only a contract few have inflicted fatal , malicious human attacks : tiger , great white bull , and white-tip oceanic sharks . Although sharks are colossal and powerful creatures , they are also very curious and umpteen attacks are they result of an exploratory bite belong to the class Chondrichthyes elasmobranchii and are tilt , but unlike 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 structure to their teeth . Studies have found that denticles create vortices that reduce drag as the shark floats to become more efficient (Hamlett , 1999Caudal fins of sharks vary betwixt species . The tail provides speed and acceleration is depended on the caudal construct . For example , the tiger shark s large upper lobe gives upper limit power and sudden busts of speed (Nelson , 1994 . An average shark impart cruise at five miles per arcminute 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 other 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 saltwater purlieu and deteriorate it over the gills . Due to the shark s large size galore(postnominal) require a higher supply of oxygen than other fish and must be continually swimming in to meet the demands or the shark will suffocate (Hamlett , 1999 . This edge is known as ram ventilation Fishes have gas-filled swim bladders - sharks do not . They have a large oil-filled liver , which can compose up to 25 percent of the metric weight unit , for buoyancy .

Nevertheless , their buoyancy is limited , and they will duck if swimming is halted (Compagno , et al , 2005 . It is also noted that if inverted , sharks take down what is called a natural state of tonic immobility . Researchers wont this as a safe handling technique (Pratt , et al , 1990Carnivorous sharks do not have teeth at the mandibula , but embedded in the flesh that are forever replaced throughout the shark s life . 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 purposes from gripping , cutting or suppression shellfish (Hamlett , 1999 have keen olfactory senses that can ferret out one part per million of blood in their environment . rely on the sharp sense of smell to take note prey . Their sight is similar to vertebrates that consist of lenses , corneas , and retinas Hamlett , 1999 . eyesight is equal to dark waters with the help of a specialized thread 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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