Shark
Sharks are approximately 350 species of cartilaginous fish of the order Selachimorpha, inhabiting the world's oceans and several freshwater lakes and rivers.
| Shark | |
|---|---|
| |
| Oceanic whitetip shark (Carcharhinus longimanus) | |
| Scientific classification | |
| Kingdom Information | |
| Domain | Eukaryota |
| Kingdom | Animalia |
| Subkingdom | Biliteria |
| Branch | Deuterostomia |
| Phylum Information | |
| Phylum | Chordata |
| Sub-phylum | Vertebrata |
| Infraphylum | Gnathostomata |
| Class Information | |
| Class | Chondrichthyes |
| Sub-class | Elasmobranchii |
| Order Information | |
| Superorder | Selachimorpha |
| Population statistics | |
Behavior
Many species of sharks give birth to a few dozen live young, others lay a similarly small number of eggs; these are often washed ashore and are known as mermaid's purses.
Sharks are reputed to be able to detect minute amounts of blood in water, and to be able to follow blood trails for miles. In fact, although sharks can detect blood at concentrations of as little as a few parts per billion, a very considerable quantity must be spilt before it is detectable amongst billions of gallons of seawater. Sharks actually use sounds and vibrations to locate most of their prey.
Classification
Sharks belong to the holobaramin that also includes skates and rays.
Environmental Concerns
Worldwide, sharks suffer threats from over-fishing, mercury poisoning, ocean acidification, and habitat disruption. [1]. Many individual shark species are currently threatened or endangered, often because of human activities such as careless fishing practices and coal fired plants dumping tones of toxic mercury into the oceans.