fish-swimming - turning movements The pectoral and pelvic...

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3 Swimming Swimming Fish swim by contracting the muscles down each side of the body in turn. The muscles pull on the vertebral column and produce wave-like undulations which travel down the length of the fish pushing sideways and backwards against the water. The sideways components cancel each other but the resistance of the water to the backwards component causes the fish to move forwards . The thick arrows show the movement of the body. The thin arrows show the reaction of the water roll yaw pitch The fins help maintain the stability of the fish. The dorsal and ventral fins reduce the tendency to roll and yaw. they also assist in
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Unformatted text preview: turning movements. The pectoral and pelvic fins act as hydroplanes and control the pitch. The tail fin contributes to the forward thrust. Fish other than those in the shark family have an air bladder just below the vertebral column. This increases the buoyancy of the fish and prevents it from sinking when it stops swimming. The pressure in the air bladder can be adjusted for changes in depth. Shark (Note the separate gill slits) Not all fish are as streamlined as the shark. The sea horse has a rigid body and swims by undulatory movements of its dorsal fin Sea horse (not to scale) dorsal fin © D.G. Mackean...
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This note was uploaded on 11/29/2011 for the course BIO 218 taught by Professor Young during the Fall '11 term at BYU.

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