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Evolution Of Sharks Essay

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Amongst the many living creatures of the aquatic world lurks an evolutionary advanced species called Selachimorpha, commonly known as Sharks. Sharks are the most dominantly feared creatures of the marine world. Although they are perceived as a threat to humans, these animals keep marine organisms in check. Sharks have developed a unique physical structure that enables them to efficiently hunt prey while simultaneously playing a vital role in balancing the ecosystem. These apex predators fall under the classification class Chondrichthyes, which is comprised of cartilaginous skeleton. Chondrichthyes is sub-divided into two classes; the Elasmobranchii, composed of sharks, skates and rays, and the Holocephali (“Shark Taxonomy” 8). As we move further down the scientific classification, identifying these similar looking creatures become more difficult. Their order is separated into two super-orders, which are the extinct Cladoselachimorph and the Euselachii; composed of 12 orders of which only nine are amongst us today (9). Many scientists believe that sharks descended from an eyeless, finless, and boneless leaf shaped fish and that they came to existence at around 400 million years ago (“Shark Evolution” 1). Documented fossil records show that there were over 3,000 types of sharks and may have existed at the same period of time (Jones, “The Epic History of Sharks”). The reason it is difficult to discover them all is due to the rotting of the cartilaginous bone structure (“Shark

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