Term
| Inherent difficulties in swimming |
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Definition
1) Water is 800 times denser than air
2) 50 times more viscous than air
3) Much less O2 for respiration |
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Term
| selective force in water so system has evolved to: |
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Definition
1) Minimize energy requirements
2) increase acceleration and speed
3) Improve manueverability
4) Compromise between and fine tuning of 1,2,3. |
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Term
| Mechanics of moving through water |
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Definition
Motion is a balance between two hydrodynamic forces; those that resist and those that generate motion
Resistance=inertia+drag
Inertia: Energy required to start something in motion
Drag: force that acts backwards along the direction of motion |
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Term
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Definition
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Term
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Definition
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Term
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Definition
1) Fusiform body shape (reduces pressure drag)
2) Mucous/slime
3) Fins tuck into folds in body
4) Vortex generators |
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Term
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Definition
| Placoid and ctenoid scales may have evolved independently in sharks and teleosts (respectively) to retard separation of the boundary layer. Small vortices prevent larger ones and help stabilize the boundary layer.
[image] |
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Term
| Two forces that enhance propulsion |
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Definition
Lift: Force perpendicular to direction of motion. Keeps object aloft in the water column. Pressure inversely related to water velocity.
Thrust: Linear (directed straight ahead) exerted by fish to propel itself: Created in two ways |
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Term
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Definition
Undulatory: Wave of increasing amplitude passes along length of body (head to tail) Generated by body and tail
Oscillatory: Structure pivots back and forth on its base. Generated by paired fins and caudal fin-movement from side to side |
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Term
| Mechanics of undulatory motion |
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Definition
1) Wave of muscular contraction from head to tail and tail swings back and forth
2) Strength of contraction and amplitude of wave increases toward posterior of fish.
3) Uses head as fulcrum
4) Portion of wave/fish that puses against water creates reactive force against/opposite pushing called normal force |
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Term
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Definition
| Normal force has 2 components: Side and thrust.
The side forces cancel when body/tail move back and forth: net resultant direction of force=thrust
[image] |
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Term
| How are contractions generated to create undulatory motion |
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Definition
Interaction between
I) Skeleton
a) head/skull
b) Vertebral column
c) Appendicular skeleton (pelvic and pectoral girdles)
II) Muscles (myomeres)
III) Fins - median (dorsal and anal fins) and caudal |
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Term
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Definition
| Vertebral column composed of linear array of vertebrae, each vertebra consists of centra with neural and hemal spine. Vertebrae are precaudal (anterior, with ribs) and caudal (posterior with haemal spine)
[image] |
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Term
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Definition
1) Flexors - Extensors: lateral musculature along sides of body, move vertebrae side to side.
2) Protractors - Retractors: Erect and depress the dorsal and anal
3) Adductors - abductors: Move paired fins toward and away the body |
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Term
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Definition
| Subdivided into serially arranged myomeres/myotomes bounded by connective tissue (myosepta) to which muscle fibers attached. Arranged in epaxial and hypaxial bundles (above and below vertebral column). Mytomes on either side of the fish move the vertebral column from side to side. One side flexes while the other side extends. Spiraling of fibers and W shape allows all fibers to contract at the same speed - effecient.
[image] |
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Term
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Definition
| All muscles on one side contract simultaneously (startle reponse) Done by manther cells, giant axons, one the length of each side, that bypass normal system. found in teleosts, not sharks |
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Term
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Definition
mass: little
blood supply: rich
myoglobin: more (high affinity for O2)
shape: fibers more slender and longer
contraction speed: slower
mitchondra: higher density
fat content: More
Operate aerobically
Slow continuous swimming (pelagics) |
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Term
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Definition
Mass: lots
blood supply: lower
myoglobin: less
shape: thicker and shorter
contraction speed: faster
mitochondria: Lower density
fat content: less
Operate anaerobically
Short bursts of rapid swimming (btm fish) |
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Term
| wing like oscillatory swimming |
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Definition
| Thrust generated like a wing (and propeller) generates lift. Like a wing on a stick |
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