WILD 3580 1st Edition Lecture 10Outline of Last Lecture I. Gnathostomata AdvantagesII. Early GnathostomesIII. Modern Boney Fish IV. Characteristics of Most TeleostsV. Natural History of Fish Outline of Current Lecture I. RespirationII. Buoyancy Regulation III. Gas Release/Addition IV. Sound reception V. LocomotionCurrent LectureI. Respiration - Evolved to get oxygen out of water efficiency through countercurrent exchange - High to low gradient between water and blood- Gill filaments increase surface area - Primary and secondary lamellae hold gill filaments - Only functions when water is moving across the gills o Gill pumping: synchronized pressure changes in the buccal (mouth) and opercular(gills) chamber s Creates a pressure lower in the operculum so water can flow outo RAM Ventilation: mouth open while swimming Fish that don’t have operculum (ex. Sharks) - Some fish obtain oxygen through aerial respirationo Aerial respiration: O2 from the atmosphere Places were fish live in poor oxygenated water (Ex. Lungfish) These fish are called facultative air breathers- use atmospheric O2 as a supplement (optional)- Obligate air breathers – must have access to atmospheric O2 Organs- lung like structures, skin, swim bladderII. Buoyancy Regulation- Very energetically expensive These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Fish have adaptations to maintain balance in the water column o Swim/ Gas bladder- a flexible gas filled chamber in the body cavity Fish that remain mostly in the bottom of the water, they have none or small gas bladders Forms as an out pocket of the esophagus during embryonic development - Pneumatic duct connect the bladder to the esophagus and is a condition called physostomous gas bladder ( fish who breath atmospheric O2)- Physoclistous gas bladder conditions: pneumatic duct not retained Maintain position in the water column ( increase volume, increase buoyancy) Neutrally buoyant: maintaining a position in the water column without expending energy Functions- buoyancy regulation, respiration, sound reception III. Gas Release/ Addition- Physostomes release gas through the esophagus- Physoclists release gas through the bloodstream o Oval body: high vascularized part of the gas bladder (capillaries) to move/release gases- Adding gases involves moving gases from the blood to the oval bodyo Gas gland: part of the gas bladder that contains a rete mirable system (veins and arteries lying adjacent to each other but flowing in opposite directions) IV. Sound Reception- Otoliths: “ear stone” fish usually have 3 to hear o Non compressed sound waves because they are o the same densities o Otoliths are different densities to convert sound waves into movemento Balance equilibrium o Can determine age of fish Gas bladder can be used to enhance hearing Weberianossicles- series of bones connects gas bladder to otolithsV. Locomotion- How an animal moves through its environment - Fish move through an aquatic median- Energetically expensive (fish are efficient) o Body shape- long, relative to its depth (1:4) stream like 25% of length Most efficient is fusiform shaped- fish that rely on
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