Difference between revisions of "Shark"
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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. | 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. | ||
| − | == | + | ==Descent== |
| − | + | According to evolution, sharks had evolved into forms that are reasonably easily classified as "sharks" over 450 million years ago. 300 to 150 million years ago, sharks had evolved into two reasonably distinct groups. "Modern" sharks appeared relatively recently, about 100 million years ago. One of the most impressive ancient sharks was the massive megalodon. | |
| + | |||
| + | According to [[Young Earth Creationism]], sharks likely belong to the [[holobaramin]] that includes skates and rays. This holobaramin was allegedly created on the sixth day of Creation, ''ex nihilo''. Post-diluvian dispersal is not necessary, as sharks are not terrestrial. | ||
==References== | ==References== | ||
Revision as of 02:36, June 4, 2007
Sharks (suborder Odontoceti) are a large group of predatory cartilaginous fishes, including the largest fish species in the world, the Whale shark. As well as the familiar fierce sorts of shark, the family also includes various dogfish and the bottom-living wobbegong.
A shark's most notable characteristics include a prominent dorsal fin, fully replaceable teeth (with the exception of the whale and basking sharks) and a cartilaginous skeleton.
Species of shark
- Whale shark.
- Basking shark.
- Great white shark.
- Mako.
- Porbeagle.
- Tope.
- Whitetip reef shark.
- Oceanic whitetip.
- Blue shark.
- Tiger shark.
- Greenland shark.
- Megamouth shark.
- Nurse shark.
- Hammerhead shark.
- Bull shark.
- Ganges shark.
- Leopard shark.
- Wobbegong.
- Port Jackson shark.
- Cookie-cutter shark.
- Goblin shark.
- Dogfish.
and many others.
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.
Descent
According to evolution, sharks had evolved into forms that are reasonably easily classified as "sharks" over 450 million years ago. 300 to 150 million years ago, sharks had evolved into two reasonably distinct groups. "Modern" sharks appeared relatively recently, about 100 million years ago. One of the most impressive ancient sharks was the massive megalodon.
According to Young Earth Creationism, sharks likely belong to the holobaramin that includes skates and rays. This holobaramin was allegedly created on the sixth day of Creation, ex nihilo. Post-diluvian dispersal is not necessary, as sharks are not terrestrial.
