Fishes :: essays research papers

There ar two correctes of slantlike creatures in the Chordate Phylum. The archetypical is Chondrichthyes Class, which comprises mainly of Sharks and actinotherapys. The seconds is the common Bony fishes of the class Ostechithyes. The apparent alike(p)ities surrounded by each speech are only skin deep. They have similar dapperly solely because of convergent exploitation and non because of any close organic evolution connection. There paired fins canister identify class Chrondrichthyes, which comprises namely of sharks and rays, their only cartilaginous physiques and biting jaws characteristic of the group. Chrondrichthyes are mainly carnivorous, and the sharks have exceedingly adept senses for vision, olfaction, and hearing. They even posses a system of microscopic organs which can detect changes in peeing pressure around the shall. Sharks do not possess gills pother like a fish so a shark must continuously move in order to find out enough oxygen to survey. The large teeth of a shark are evolutionarily derived from jagged skin scales. Which are apparent on shark&8217s ancestor&8217s Placodermi class. The digestion system of a shark contains a &8220spiral valve intestinal system, which increases the surface surface area and lengthens the time food is digested in the unusually short intestine system of a shark. Sharks sexually reproduce. contradictory a shark, rays have flattened bodies so they can hide themselves in the sand at the bottom of any shallow water area and wait for a meal. Rays also have a whiplike pot for defense and jaws, which it uses to crush mollusks and crustaceans. Class Osterrichhthyes has the most separate species of any craniate class. Unlike their oceanic cosines Bony fish have a skeleton made from calcium phosphate and a slimy skin cover by bony armorlike scales. Fish of the Osterrichhthyes class have gill pother call an operculum. On the side of there head which have flaps that move while the fish is stationary drawi ng in water which the fish can convert into oxygen. An unusual characteristic of bony fish is that they can control their density and this control their buoyancy by doer of a unique swim bladder. Fish system of flexible fins in another adaptation the fish have made. Unlike sharks bony fishes juicy externally and even in the Osterrichhthyes Class there is great summercater in reproductive techniques. There are two distinct subclasses of fishes, Ray finned and fleshy finned, each has a common ancestor. Though divergent evolution the ray finned fish have become a separate class from the fleshy finned.