The Fish

THE FISH Osteichthyes-Bony look for (eg.Tilapia sp.) nearly bony look for move to the group of ray-finned fish called Teleostei. Most food, sport and aquarium fish belong to this group. About 30000 species and sub-species atomic number 18 known. home ground Bony fish occur in sea pissing, impudent and estuaries. External characteristics The frame is divided up into head,trunk,and tail.On the head atomic number 18 a mouth, dickens large eyes, two external nostrils for smell and an operculum(a bony plate which covers the gill-slits)one each view of the body. The trunk is bi squint-eyedly flattened and covered with dermal scales. The diametrical fins are the pectoral muscle muscle and pelvic fins. The dorsal fin git be p transported or unp product lineed. Ventral, just before the anal retentive fin opens the cloaca. On either side of the body is the squint line (a group of sensory organs) which detects streaming fecal matters and vibrations in the water with wh ich the fish determines its depth. The tail is muscular. Locomotion The fins control locomotion, which is caused by the muscular taillike (tail) fin of the fish. Fig.1:The dorsal and pelvic fins avail to keep the body upright when the fish makes a choppy change of direction. The pectoral and pelvic fins balance and steer the fish as it moves.

The taillike fin curves slowly outwards and then rapidly acantha to the midline, the tail thus presses backwards against the water and in this stylus the fish is driven forward. This action is repeated on the other(a) side causing a further forward effect of the fish. Th e be adrift bladder, is situated in the tr! unk, below the vertebral column. most fish fill the swim bladder by see in railway line at the waters surface, others slowly fill the swim bladder with oxygen diffusing into it from the surrounding blood-vessels. Likewise, the volume of atm can be reduced by letting air out... If you want to get a full essay, order it on our website: BestEssayCheap.com

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