LOCOMOTION IN A FISH ( 10 marks max)-
Ø The muscles consist of muscle blocks i.e., MYOTOMES arranged in segments on both sides of the vertebral column.
Ø The muscles act antagonistically.
Ø Contraction of myotomes on one side of the vertebral column and relaxation on the other side
Ø Causes the body to bend in a direction of the contraction
Ø Alternate contractions of the right and left myotome blocks causes body to bend side to side and the tail to bend accordingly.
Ø This produce a forward thrust which propels the fish forward
Ø Presence of fins i.e. dorsal and ventral fins, paired pectoral and pelvic fins.--- for stability
Ø The streamlined shapes –--to overcome water resistance and enable to move quickly in the water.
Ø The skin is covered with scales that have slimy coat---help reduce water resistance
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