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BIO358 1st Edition Lecture 8Outline of Last Lecture I. What is challenging about living in water? A. Imagine yourself in the oceanB. Physical properties of water C. Heat conductivity coefficient II. Solutions to living in water A. Structure of the integument B. Fur Density (fur seals and otters) C. Blubber (cetaceans and other otariids) D. What about polar bears? Outline of Current Lecture I. ReviewII. How do marine mammals dissipate body heat? A. Counter current heat exchange III. Enhanced sensory systemsA. Echolocation/biosonarCurrent LectureLarge body size = large SA/V ration = Large volume of tissue generating heat relative to the amount of surface area exposed to the environment. Insulative material of integument are important to reducing heat loss.Epidermal solution of fur and the hypodermal solution of blubberFur seal and otters use fur. Everyone else EXCEPT for the polar bear use blubber. 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.Thick integument formed by blubber or fur to insulate the large body against heat loss. Dissipate body heat? i.e. vacation in the tropics… out in air (very insulated) needs to dissipate heati.e. Dolphin or blue whale going for a hard fast swim… need to dissipate body heat to dissipate excess body heat, marine mammals must be able to by-pass their insulationTHIS REQUIRES NON-INSULATED SURFACES CALLED THERMAL WINDOWS Visualize: 5 k run on a day in august in Wilmington. You turn red because you are shunting blood to the surface of your body. How are animals not constantly dumping heat through thermal windows. They need to be able to turn on or off… dynamic Thermal Windows (requirements):1. uninsulated - no fur no blubber2. large, flat plate shaped structures= relatively large SA3. specialized vascular structures including superficial veins to dissipate heat 4. Deep counter current heat exchangers using deep veins and central arteries to conserves heatSteps of cooling:1. Arteriole blood travels too the thermal window 2. Warm blood shunted to the surface of the thermal window3. heat is lost to the environment across the surface of the thermal window4. cooled blood is carried back to the body via superficial veinsThermal windows must be dynamic turn on and off. blood flow is changingCounter Current Heat Exchanger (CCHE):1) pipes that are juxtaposed 2) the flow of fluid in those pipes is in the opposite direction (i.e. counter current flow) 3) temperature differential between the fluid flowing through the pipesarteries carry warm blood to the thermal windowveins are carrying cool blood from the thermal windowTransfer of heat to the veins to conserve body heatBottlenose dolphin dorsal fin: - Central arteries go into the dorsal fin - Cross section = regularly placed central arteries (brings warm blood to the fin)- Superficial veins closer to surface- Separate set of veins = rosettes completely surrounding each central artery = counter current heat exchanger Conductance ( C ) is dynamic – dependent upon blood flow to thermal windowns and body surfaces. Review – Characteristics of large mammals- Large body size- Streamlined body- Reduced appendages- Enhanced insulation - Enhanced diving- Enhanced sensory system SENSORY SYSTEMS: Vision = important sensory modality for most terrestrial mammals… BUT light doesn’t transmit well through water…. Light energy is attenuated drastically in water compared to in air… Functional problem = vision is not as functional at depth and with turbidityFunctional solution = use another sense, hearing! Water transmits sound much more effectively than air… Low frequency sound is attenuated 6 million times faster in dry air than in water. So sound is good to usein water Odontocete echolocation AKA biosonar (sonar = SOundNAvigaiton and Ranging) Sound is a wave that is created by vibrating bodies and propagated through a medium (air, water, solid) from one location to another…. A wave is a disturbance that travels through a medium transferring energy from one medium to another. Talking = vibrating = pressure wave = transferred to ears = transduced to neuro signal…. Visualize pressure with pressure and time as a sinusoidal wave. Peak = compression Valley = expansion Amplitude (Height of wave) = loudness of sound Measured on a decibel scale which is a log scale - dB = 20 log (pm/pr) - pm = measured pressure- pr = reference pressure (1 uPascal in water)- 100 fold increase Quiet whisper = 30 decibelsHearing loss = 90-95Concerts = 150 Log scale so these differences are much larger than they seem Frequency = number of pressure waves per unit time measured in Hertz (cycles/second)Biosonar sounds = so high you cant hear them = ultrasonic (50-130 kHz) = this means something in the head of a bottlenose dolphin is vibrating very fast! Ken Norris = put little blind folds on dolphins (suction cups) - Discrimination tasks, dolphins could do this with the blindfolds- Dropped a hydrophone in the water when the animal was making these discriminations - Ken Norris helped recreate the field of marine mammal biology Biosonar system: 1. A receiving system a. Auditory system (ear) lower jaw (pan ) fat 2. Transmitting systema. Monkey lips-dorsal bursae (MLDB), nasal system, melon3. Signal processing system a. Acoustic nerve and CNS Receiving system human: - Pinnae funnel sound into the human external ear canal that ends in the ear drum. - 3 oscicles in the middle ear move and the oval window sets up fluid filled channels in the inner ear. - External, middle, and inner earBottlenose hearing: - Tiny hole behind the eye, lacking pinnae - middle ear: specialized bulla(with middle ear ossicles) also called tympanic bulla- Jaw has a “pan” - thin caudal end of the mandible close proximity to bulla expanded pan of boneis filled with


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