Fish do not all have the same skeletal structure? most primitive to more advanced types. ?

Question

fish do not all have the same skeletal structure? Describe the differences among fish from the most primitive to more advanced types.

Could you help me with this or point me in the direction that i can locate this information, my attempts haven't fair-ed so well.

Thanks

Answer 1

Look over a phylogenic tree and you will see that Sarcopterygians are fleshy-finned (lobe-finned) fish while Actinopterygians are ray-finned fish but both groups have bony jaws. The other main branch, the Chondrichthyes, does not have calcified bones but a cartilage-based skeleton.

http://www.factmonster.com/ce6/sci/A0858...

Actinopterygii

http://www.ucmp.berkeley.edu/vertebrates...

http://tolweb.org/Actinopterygii/14923

http://www.devoniantimes.org/who/pages/r...

Sarcopterygii

http://www.ucmp.berkeley.edu/vertebrates...

http://tolweb.org/tree?group=Sarcopteryg...

http://www.devoniantimes.org/who/pages/l...

Chondrichthyes

http://www.ucmp.berkeley.edu/vertebrates...

http://www.devoniantimes.org/who/pages/s...

Time-line for development

http://www.devoniantimes.org/opportunity...

http://serendip.brynmawr.edu/exchange/no...

http://www.arn.org/blogs/index.php/liter...

http://museumvictoria.com.au/About/MV-Ne...

http://news.bbc.co.uk/1/hi/sci/tech/7424...

Answer 2

Fish are divided into two large groups, the chondricthies and the ostithcies, based on what their skeletons are made of.  Start with sharks skates and rays in wikipedia.