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14 Cards in this Set
- Front
- Back
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Holo-epipelagic
Mero-epipelagic |
live in epipelagic throughout life
Tuna, many spawn in epipelagic but juveniles develop elsewhere (e.g. esturaries) |
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How do nekton swim so fast?
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) Nekton use propulsive force to move through the water, and reduce resistance by streamlining
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– aspect ratio
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fin height2/fin area
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Rounded with aspect ratio =
Truncate with aspect ratio = forked with aspect ratio Lunate with aspect ratio = In sharks: • Heterocercal with aspect ratio |
1
3 5 7-10 2 |
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Why are tuna so fast?
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• Optimal streamlining
• Efficient caudal fin to generate thrust • Reduced drag due to – small scales, non-bulging eyes, and small medial finlets Muscle composition |
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Whales
seals/walruses |
(Cetaceans)
(Pinnipeds) |
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Lateral line system
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•Rows of small tubes that are open to seawater
–Sensitive to pressure changes •Found in schooling fish |
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• SR (sinking rate) =
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(w1 - w2) / R * Vw) where w1 is the density of an organism, w2 is the density of seawater, R is the surface resistance and Vw is the viscosity of water (related to temperature and salinity)
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• Density reduced by
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–manipulating ionic composition
–using lipid storage reserves –maintaining gas-filled inclusions |
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siphuncle
•Depth limit for Nautilus |
tube like tissue that connects inner tissues in nautilus
500m |
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Two types of swim bladders:
•Physostomous Physoclist |
• type has a duct to connect to the esophagus (salmon)
•lacks a duct (more common type) |
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Counter-current exchange system (rete mirabile system)
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– Incoming vessels low in oxygen and outgoing vessels rich in oxygen run side-by-side
–Diffusion concentrates oxygen in the incoming vessel |
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spermaceti organ
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•Fat-filled melon in sperm whales generates and focuses (as an acoustic lens) sounds
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Great white shark
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carcharodon carcharias
• Stealthy approach along the bottom (strong countershading helps), swim up from below and bite prey •Prey is pulled underwater and held until it dies |
