Fishes :: essays research papers

There atomic number 18 two ground leveles of leanlike creatures in the Chordate Phylum. The for the first time is Chondrichthyes year, which comprises mainly of Sharks and Rays. The seconds is the super C Bony fishes of the class Ostechithyes. The app bent similarities amidst each speech are only skin deep. They shoot similar dapperly solely because of convergent ontogeny and not because of any close evolution connection. There paired fins brush off identify class Chrondrichthyes, which comprises namely of sharks and rays, their only cartilaginous skeletons and biting jaws characteristic of the group. Chrondrichthyes are mainly carnivorous, and the sharks invite extremely adept senses for vision, olfaction, and hearing. They even posses a organisation of microscopic organs which can detect changes in water pressure around the shall. Sharks do not possess gills flaps like a fish so a shark must continuously move in order to retain enough oxygen to survey. The large t eeth of a shark are evolutionarily derived from jagged skin scales. Which are apparent on shark& group A8217s ancestor&8217s Placodermi class. The digestion system of a shark contains a &8220spiral valve intestinal system, which increases the surface battlefield and lengthens the time food is digested in the uncommonly short intestine system of a shark. Sharks sexually reproduce. Unlike 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 tail for defense and jaws, which it uses to crush mollusks and crustaceans. Class Osterrichhthyes has the more or less separate species of any vertebrate class. Unlike their oceanic cosines Bony fish have a skeleton made from calcium phosphate and a slimy skin covered by bony armorlike scales. lean of the Osterrichhthyes class have gill flaps call an operculum. On the side of in that location head which have flaps that move while the fish is unmoving drawing in water which the fish can convert into oxygen. An unusual characteristic of bony fish is that they can examine their density and this control their buoyancy by means of a unique swim bladder. Fish system of flexible fins in another adaptation the fish have made. Unlike sharks bony fishes fertile externally and even in the Osterrichhthyes Class there is great variation 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 run short a separate class from the fleshy finned.