Respuestas
Respuesta:
Like the rest of vertebrates, fish have an external skeleton or "exoskeleton" and an internal skeleton or "endoskeleton".
The exoskeleton is formed mainly by the scales and the spines and rays of the fins. While in most fish the surface of the body is covered by various types of scales, in cyclostomes such as lampreys and witchfish, the skin is bare. In chondrichthyans such as sharks and rays, the skin is covered by small, plate-like scales, called placoid scales. In osteíctios such as sardines, trout, crappie, piranhas, guppies, mullet, snook, snapper, barracuda, tuna, sole, etc., the skin is covered by thin and overlapping scales called cycloids or ctenoids.
The endoskeleton is made up of bones or cartilage, which constitute the structure of the body and its parts, which protect certain organs and serve for the fixation of numerous muscles, which in turn, provide movement of the parts and locomotion.
The edoskeleton is divided into the following components:
Somatic skeleton
Axial: skull and spinal column.
Appendicular: shoulder girdle and pair of pectoral fins or their modification in forelegs pelvic girdle and pair of pelvic fins or their modification in hind legs
Visceral skeleton
Mandibular arch
Hyoid arch
Gill arches
The study of the skeleton of vertebrates has allowed us to know the evolution of the classes, both fish and tetrapods, since they are the parts that have been preserved as fossils since the vertebrates appeared. Likewise, the study of the bones and cartilage of the different classes of vertebrates allows us to interpret the movements of the parts of the body, locomotion, as well as the form of protection of soft organs.
The most complex part of the skeleton of vertebrates is the skull, which protects the brain and the main sense organs, and also suspends the jaws. While the skull of cyclostomes and chondrichthyans is made of a single piece of cartilage, that of osteictians is made up of numerous bones, which means greater difficulty in studying them, however, it is an activity of great interest.
Explicación: