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28 Cards in this Set
- Front
- Back
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Nekton
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-Animals with swimming abilities that permit active movement in the water column. -Can move against currents.
-Members include: =>Cephalopods (Squid, octopi, cuttlefish, etc.) =>Fish =>Marine Mammals (cetaceans, otters, etc.) =>Reptiles (sea turtles, sea snakes) =>Birds (diving birds, shorebirds) |
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Cephalopods – Phylum Mollusca
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-carnivores
-complex behavior and well-organized nervous system -have grasping arms (sometimes tentacles) arranged in circles - mantle+siphon = rapid movement |
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Chondrichthyes
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Type of fish
-cartilaginous fishes including sharks, skates, rays - cartilaginous skeleton, replaceable tooth rows, jaw usually ventral |
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Osteichthyes
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-type of fish
- bony fishes, true bony skeleton - much more diverse than Chondrichthyes, teeth fixed in jaws, jaw coincides with midline |
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Rover predators
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- form of a fish
-long and torpedo-shaped, with fins spaced along body for maneuverability, nearly all thrusting power is in tail |
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Lie-in-wait predators
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-form of fish
-torpedo shaped, fins concentrated towards rear to provide sudden thrust |
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Surface-oriented fishes
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-form of fish
-(e.g. flying fishes) -mouth oriented upward to capture prey at surface |
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Bottom fish
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-form of fish
-variable, but often flattened to be close to bottom |
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Deep-bodied fish
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-form of fish
-flattened laterally, excellent at maneuvering, not prolonged swimmers -(the pretty colorful type) |
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Eel-like fish
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-form of fish
-well adapted to moving in crevices, such as moray eels |
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Three main functional components of swimming in fish
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1- Acceleration – maximized by propulsion of a strong caudal fin, allows for rapid movements
2- Cruising – continued undulation of body 3- Maneuvering – best with disc or diamond-shaped body, permits flexibility and sudden changes of direction |
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Buoyancy in fish
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-Fish can regulate bulk chemistry
=>Sharks - high lipid content in liver - reduces bulk density =>Bony fish - lower salt content than sea water - reduces bulk density -Swim Bladder - most (but not all) bony fish =>absorbs or secretes gas to adjust depth at which the fish is neutrally buoyant =>esophagus is connected to swim bladder for some fish, so they can just swallow air =>Gas gland – controls gas uptake and release =>Rete mirabile -intertwined capillaries and veins - countercurrent exchange to retain oxygen near the gas gland |
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Sensory Perception in fish
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-Lateral line system – series of mechanoreceptors linked to the brain by nerves – detects water movement/disturbances
-Eyes - fish often have excellent vision -Inner ear – hearing and balance =>Otoliths in contact with hairlike fibers, pressure of otolith against fibers provide spatial orientation info -Electroreceptors – detect electrical currents generated by movement (i.e. by prey). Cartilaginous fish and some bony fish |
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Body temperature in fish
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Poikilotherms- temperature conformers, most fish fall into this category
-Endothermy - Tunas and relatives, some sharks, use countercurrent heat exchange to reduce heat loss - have elevated body temperature =>Elevated body temperature allows higher metabolic rate -Localized heating of nervous system in some species (e.g., swordfish) |
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Mesopelagic Fishes
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-Fish living 150-1000 m
-May have well-developed musculature -Eyes are adapted for low light - Some have very large mouths for feeding on large prey -Reproduction – Hard to find a mate – some species are simultaneous hermaphrodites, some have dwarf males -Many have ventral photophores, serves purpose of counterillumination - camouflage to blend in with low light from above |
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Bathypelagic and Abyssopelagic Fish
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-Bathypelagic – depths of 1000-4000m
-Abyssopelagic – depths of 4000-6000m -Have poor musculature and incompletely ossified skeletons -Usually lack swim bladders -Fairly inactive, feed only occasionally -Dominated by eel-like forms (good lateral line system) |
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Mammals
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-Cetaceans
=>Suborder Odontoceti = toothed whales (sperm whale, killer whale, porpoises, etc.) =>Suborder Mysticeti = baleen whales (blue, humpback, grey, etc.) -Pinnipeds: seals, sea lions, walruses -Mustelids: sea otters -Sirenians: sea cows, dugongs |
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Cetaceans - Whales and Porpoises
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-All homeothermic
=>thick sublayer of fat to reduce heat loss, countercurrent heat exchange -Body is elongated and streamlined -Posterior strongly muscular - propulsion by means of flukes – efficient swimmers -Reproduce much the same as terrestrial mammals -Air breathers, must return to surface for oxygen, nasal opening is a blowhole |
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How do marine mammals avoid running out of oxygen on long dives?
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-Increased volume of arteries and veins
-Storage of O2 attached to hemoglobin in muscles -Increased blood cell concentration -Decrease heart rate and O2 consumption -Restrict peripheral circulation and circulation to abdominal organs |
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Bottom up control
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-control of food chain by amount of primary production
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Top-down control
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-control of food chain by variation in top predators
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Trophic Hypothesis
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-there is a maximum number of trophic links through which energy can travel
=> With ecological efficiency of 10%, only 0.01% will reach a 5th trophic level =>May set a limit to upper trophic levels → bottom-up control |
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Food Chain Stability Hypothesis
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-Longer food chains are inherently unstable
-Changes at one level will propagate to other levels -If a population at one trophic level goes extinct, it will cause species at levels above it to go extinct |
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Gross primary productivity
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- total carbon fixed during photosynthesis
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Net primary productivity
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-total carbon fixed during photosynthesis minus that part which is respired
=>gives that part of the production available to higher trophic levels |
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Light-Dark bottle technique
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Measuring Primary Productivity – Oxygen Technique
-Light = oxygen from photosynthesis minus respiration -Dark = respiration only L – D = (I + P – R) – (I – R) = P I = Initial amount of oxygen in bottle P = Oxygen produced in photosynthesis R = Amount of oxygen consumed in respiration |
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Radiocarbon Technique
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Measuring Primary Productivity
-14C is a label to measure total carbon uptake in photosynthesis -Method: add known amount of 14C-labeled bicarbonate to solution with phytoplankton -After a time: filter phytoplankton, and count 14C with a scintillation counter -Know proportion of 14C in total bicarbonate: allows calculation of total carbon removed by cells from solution |
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Remote Sensing
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Measuring Primary Productivity
-Satellite color scanners can give an estimate of photosynthetic pigment concentration -Relationship between chlorophyll concentration and primary production varies with region =>Need ground-truthing to determine relationship |
