Form And Functon Flashcards
(26 cards)
What is the Reynolds number?
Non-dimensional measure of the relative importance of viscous to inertial forces. The ratio of one to the other.
What are the implications of living at high Reynolds number?
Inertial stresses dominate and influence:
- Swimming and functional morphology
- Respiration (e.g., ram ventilation)
How are organisms streamline?
Streamlined in the direction of the flow
What is drag?
The rate of removal of momentum. Can be form or friction drag
What are some basic body shapes seen in fishes?
- Surface-oriented
- Rover-predator
- Deep-bodied
- Lie-in-wait predator
- Rat tailed
- Eel like
- Bottom rover
- Bottom clinger
- Bottom hider
- Flatfish
What are the primary forces involved in fish swimming?
Thrust: Force that propels forward
Drag: friction produced from passing an object through a medium
Gravity: force from earth’s magnetic pull
Lift: upward force that counteracts gravity
What are different types of swimming styles seen in fish?
Body waves - anguilliform
Partial body waves - (sub) Carngiform
Caudal peduncle/fin beats - ostraciform
Medial fin waves - amiiform
Pectoral fin beats - labriform
What is anguilliform swimming?
Lateral curvature in the spine and musculature that moves in a posterior direction. Results in a backwards faxing wall of body pushing against the water.
What is partial body waves (Sub) Carangiform?
Body wave begins posterior to head and increases with amplitude as it moves posteriorly. Reduced drag compared to full body wave swimming. Wave starts at the caudal peduncle (deeply forked, lunate).
What is caudal peduncle/fin beats?
Sculling action of caudal fin - like rowing. No body waves - body remains rigid - useful for odd-shaped fishes.
Example: puffer fish
What is medial fin waves swimming style?
Body is rigid, but medial find generate posterior waves (forward) or anterior (reverse).
Good for stalking or moving without disrupting body musculature that serves as electric organ (knife fish). Also used for sculling - triggerfish
What are pectoral fin beats?
Similar to rowing, laterally-positioned, pectoral fins often includes feathering as well, especially useful for fine manoeuvring (e.g/. Deep-bodied fishes).
What are some mechnisms for reducing drag in fish?
Fusiform body shape
Reduction of body wave amplitude
Reduction of fin surface area (caudal fin: forked, lunate; paired and medial fins)
Boundary layer modifications: mucous, thick and rigid skin layer, laminar jets of water by scales, micro projections.
How does the boundary layer modifications help with reducing drag in fishes?
Effectively create a turbulent boundary layer that follows the contour of the moving object, creating a smaller wake so less fluid is “carried” along with the object, reduction in drag.
What are the energetics of short fin mako sharks?
Endothermic
Homocercal or lunate tail
Keel on caudal peduncle
Streamlined
Micro projections on denticles
What is the surface-oriented body form? Give an example:
Body flattened, upturned mouth, dorsal fin far back
Adapted for: Feeding on or just below the water surface
Example: Mosquitofish, trout
What is the rover-predator body form? Give an example:
Streamline, fusiform, forked tail
Adapted for: constant swimming and chasing prey in open water
Example: Mako sharks, Tuna
What is the deep-bodied body form? Give an example:
Tall, laterally compressed (flattened side-to-side)
Adapted for: quick turns and maneuvering in complex habitats (e.g., coral reefs)
Example: John Dory
What is the lie-in wait predator body form? Give an example:
Elongated with large mouth, dorsal and anal fins are set afr back
Adapted for: burst swimming to ambush prey
Example: Pike
What is the rat-tailed body form? Give an example:
Large head, tapering tails
Adapted for: deep sea dwelling, energy conservation
Example: Rattail
What is the eel-like body form? Give an example:
Long, flexible, often lacking pelvic fins
Adapted for: burrowing or moving through crevices
Example: Moray eels
What is the bottom rover body form? Give an example:
Flattened body, horizontal mouth
Adapted for: swimming slowly along the bottom and feeding
Example: Catfish
What is the bottom clinger body form? Give an example:
Small, modified limbs, or suction discs
Adapted for: holding onto rocks in fast currents
Example: sculpin
What is the bottom hider body form? Give an example:
Small, without obvious modifications for clinging
Adapted for: hiding under rocks, sand, or within crevices
Example: blenny
