State one difference between cartilaginous and bony fishes.
Answers
Explanation:
Bony Fish
This category of fish is also referred to as Teleostomi. It is also considered the largest class in Phylum Chordata. These fish are widely recognized because of the following characteristics:
Their endoskeleton is entirely made of bone
They have anterior tip mouth opening
They can either be fresh water or marine water fishes
Their exoskeleton is made up of cycloids (thin bony plates), aligned based on whether the outer edges are spiny or smooth
They have an operculum on either side of their gills
They possess an air bladder that also performs hydrostatic functions
Their tail fin is homocercal
They fertilize their eggs externally
Some of the fish in this category include flying fish, globe fish, sea horses and eels.
Cartilaginous Fish
This category of fish is also referred to as Elasmobranchi. In this category you will primarily find marine fishes. Therefore, you should not find any fresh water fish in this group. They generally possess the following characteristics:
Their endoskeleton is primarily made of cartilage
Their exoskeleton is made of placoid (very small denticles coated with lots of sharp enamel)
The buccal cavity of these fishes is ventrally positioned
The position of their tail finds is heterocercal
On either side, they have 5 gills that are overly exposed, so they do not have an operculum
Their mode of fertilization is through internal mechanisms
Some of the common fish in this group include dog fish, skates, electric ray torpedo, and sharks. If you understand these differences, it is easier for you to tell the two types of fish apart.
The following points listed below describes the differences that can be observed between the cartilaginous type of fishes and bony kind of fishes -
1. Cartlilaginous fishes are found in marine type of habitat whereas the bony fishes can be seen in both habitats, that is, marine as well as fresh water.
2. Cartilaginous fishes possesses endoskeleton which is of cartilaginous type while bony type of endoskeleton is seen in bony fishes.
3. The mouth of cartilaginous fishes is situated in ventral position whereas the mouth of bony fishes is situated in terminal position.