There are currently more than 465 known species of sharks living on our planet today, over 500 if you count those that have sadly become extinct. They can be found in every ocean in the world, and range in size from the 8inch pygmy lantern shark, to the 60ft whale shark.
Sharks are Apex Predators – the top links of the food chain. They are crucial to maintaining the delicate balance of ocean ecosystems, by continually eliminating the weaker or injured creatures. Sharks are very efficient in this regard, hunting down the old, sick or slower fish and thus keeping the overall population healthier. This also helps maintain the populations of marine life, preventing them from becoming too populous and causing harm to the ecosystem.
Different species of shark serve different roles, each with their own unique anatomical features and behaviours.
Image credit: http://www.innovation.ca/en/ResearchInAction/ImpactStory/familytreesharks