The Demo Site

Shark or shark is a group (Superorder Selachimorpha) fish with cartilaginous skeleton complete and slender body. They breathe using gills of five holes (sometimes six or seven, depending on the species) in addition to, or started a little behind, his head. Sharks have a skin-covered body of dermal denticles to protect their skin from damage, from parasites, and to add dynamics air.Mereka has several rows of teeth that can be replaced.

The shark species include palm-sized pygmy shark, Euprotomicrus bispinatus, a species of sea in which only 22 cm long, up to the whale shark, Rhincodon typus, the largest fish, which grows to about 12 feet and that, like a whale, only eat plankton through filter device in his mouth. Bull shark, Carcharhinus leucas, is the best known of several species that swim in sea water and fresh water (this species was found in Lake Nicaragua, in Central America) and the delta-delta.


Shark is very different framework than the bony fishes such as cod, because it is made of cartilage, which is very lightweight and flexible, although cartilage in sharks older part sometimes can calcify, making it harder and more like bone. Diverse shark's jaw and is believed to have evolved from the first gill cavity. The jaw is not attached to the Cranium and has additional mineral deposits that gave it greater strength.


Sharks are generally slow to reach sexual maturity and produce very few offspring compared to the other fish are harvested. This has caused concern among biologists because of the increased effort to nab the shark over the years, and many species are now considered threatened with extinction.

Some organizations, such as the Shark Trust, a campaign to limit shark fishing.


Mythology


There is a popular myth that sharks are immune to disease and cancer; but this is not true. There are diseases and parasites that affect sharks. Evidence that the shark at least resistant to cancer and virtually disease is only anecdotal, and even if there were very few scientific studies or statistics that prove that sharks can increase immunity against disease