Biodiversity

Wednesday, May 10, 2006

MORPHOLOGICAL DIFFERENCE BETWEEN CARTILAGINOUS AND BONY FISH

Cartilaginous fish includes fish such as shark skates and rays. Shark is big. Shark has very strong teeth. Cartilage fish consists of dense connective tissues. It is also have cells which composed of Chondrocytes. This type of cartilage fish has fibre which composed of collagen and elastic fibres. Because of big teeth, it is easy for shark to break pray or to catch pray. Shark is the latest hunters of the oceans. Let’s look at Rays and Skates. These two are quiet or non-aggressive. The bodies of Rays and Skates are large. They also have wings. These wings help them to move smoothly through the water and they use tail as a wheel. Both Rays and Skates are bottom feeders. http://www.biologyreference.com/Bl-Ce/Cartilaginous-Fish.html

Although cartilage has strong jaws. The mouth of cartilage is found on the underside of the body. Where as the eyes of cartilages are found on top of the body. It is not easy for cartilage to see food. Some shark they use nose to touch their food, while on the other hand others use powerful electro sensory system to find food. Sharks, Skates and rays have rough skin. On each side of head shark has 5 to 7 gills slits. Where as Bony fish have 1 gill on each side. Chimaeras or Gost sharks’ skins are smooth and have only one pairs of external gill openings. Cartilage fish give live birth and Bony fish produces eggs. Cartilage fish lives in only salt water while bony fish lives in all types of water. Let’s look at bony fish. http://en.wikipedia.org/wiki/Cartilaginous

Bony fish is a fish that is made out of cartilage. Their liver is filled with oils and these oils keep them from sinking. Bony fish have hard cartilage for skeleton. The bony fish are classified into Lobe finned and the Ray –finned. Lobe-finned bone fish includes fish such as lungfish and coelacanth’s, where as Ray-fins includes the goldfish, tuna, and trout.
Bony fish is true fish, such as snapper, groper and gurnard. They have a bony skeleton and single pairs of external gill openings. The mouth of bony fish is found on the front of the body and they also have a tail fin, which are found on the top and bottom portions nearly the same size. Bony fish has short tube. In terms of fertilisation, bony fish reproduce by external fertilization of eggs and they release them into water. The male releases sperm. Those sperm that are released by males are called Milt. http://www.biologie.uni-hamburg.de/b-online/library/crone/3051/highli05.html

Finally, the bones of fish have calcium but Shark does not have any bones. Shark skeleton is made of cartilage, and have no bladder, but bony fish have a gas filled swim bladder which enables them to float in the water. Bony fish have movable parts were as shark does not have. Shark can turn around in a smaller space than bony fish.
On top of shark it is dark in colour which is called dorsal side, and light colour on the bottom which is called ventral.
Shark have noses that use for smelling, not for breathing one can find their pairs of nostrils on underside of their snouts. The eyeball of shaka is cornea, iris, pupils, lens and retina. Shark teeth are parallel. http://www.biology4kids.com/files/vert_fish.html

Reference

1. Studios, A.R. 1997-2006 Biology for kids’ vertebrates’ fish [Online].Available from:
http://www.biology4kids.com/files/vert_fish.html [2006, May 09 13:00]

2. Gale, T. A part of the Thomson corporation, 2006. Cartilaginous fish, [Internet]. Online [Access:2006 May 09 12:30] Available from:http://www.biologyreference.com/Bl-Ce/Cartilaginous-Fish.html

3. Hudson Valley Community College, 2000,life in the water, [Internet] Online. Access: 2006, May 09 14:00] Availible from:
http://www.biologie.uni-hamburg.de/b-online/library/crone/3051/highli05.html

4. Wikipedia contributors. [Internet].wikipedia, The free encyclopedia, 2006 May 09, 10:03 UCT. [Cited May 09] Available from:http://en.wikipedia.org/wiki/Cartilaginous

Linette Netshiheni
CSIR
Pretoria
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Cell: 0820446442
Tell: 012 841 2133
Fax: 012 842 3676
tnetshiheni@csir.co.za
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