BIO 358 1st Edition Lecture 11 Outline of Last Lecture I Requirements of feeding in water II Pinniped feeding III Mysticete feeding Outline of Current Lecture I Rorqual feeding structures II Echritiidae feeding III Feeding and conservation IV Odontocete feeding V Diving physiology a Elsner view b Kooyman view c Anaerobic metabolism d Scholander forced dives e Elsner trained dives f Kooyman weddel seal intro Current Lecture Y shaped fibro cartilage structure Y shaped cartilage Associated with ventral groove blubber and muscular layer Stem inserts on to mandibular symphisis 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 Movable joint between mandible bones can rotate in and out cartilage attached to symphisus Joint at the chin At the center of symphisus Sensory organ o Mechanoreceptor transduces mechanical stimulus tension compression shear pressure into a nervous signal o receptor aggregated and combined with cells that support and protect them amplify the environmental stimulus and help localize the source of the stimulus o sensory organ when animal opens and closes jaws space sensory organ is sitting in gets bigger or smaller o jaws closed smaller space o jaws open larger space o this tells the brain that blubber is expanding o vibrissae on chin sensory organ tactile prey sensation coordinating the initiation and the end stages of engulfment o and they discovered a new sensory organ that is 20 20 meters in length in 2012 Eschrictiidae Bottom suction feeder short coarse baleen ram head into sediment suck in sediment and have a more typical mammalian tongue sucking sediments into the mouth sucks in amphipods and inverts and spits out the sediment important bioturbaters creating open spaces for new inverts to colonize Feeding from conservation Balaenids and baleaenopterid rely upon specialized cranial morphology to capture their prey What happens when something interferes with this Mouth has to be able to be held open in a certain posture Mouth tethered shut entangled cant feed EubalenaGlacialis North Atlantic right whales only feed 4 8 months of the year and then fast Adapted to survive for months without feeding Their physiology permits them to survive extended periods of time 5 or 6 months with ultimately lethal entanglements Lethal around the mouth or pectoral flippers Entanglement in fishing gear is an important conservation threat to these endangered species Odontocetes Feed on small fish and cephalopods large whales orcas eat spermwhales Suction feeders cephalopods physeterids kogiids ziphiids and some delphinids Ram feeders fish and mammal eater s delphinids Orcas during pupping season multiple tones throws its self out of the water to catch sea lions cultural transmission of feeding styles Sometimes they get stuck Learned behavior killer whales taught to do this Bottlenose dolphins cultural transmission of feeding styles dolphins group feed one dolphin stirs up the mud and mullet fly into the mouths of other dolphins Diving Physiology Balanced Growth Equation Injestion Somatic Growth Reproductive Growth Respiration Egestion Excretion Work Energy In Energy Out or used Metabolic rate MR rate of energy usage measured as oxygen consumption rate Diving is Work Swimming foraging seeing food capturing food digesting food but the diving metabolic rate is equal to or less than the resting metabolic rate Why Access to Oxygen and access to prey energy in needed for survival Access to oxygen surface Access to prey below the surface All of marine mammals things for life other than oxygen are done in a breathold apnea 2 alternate paradigms for diving Defense against asphyxia the moment an animal takes a breath it is taking a slow and stead path to asphyxia Elsner Most dives are aerobic kooyman o Plenty of onboard oxygen store using oxygen very efficiently Forced dive experiments Irving and scholander 1930 s Pinniped restrained and submerged the head underwater o Extreme bradycardia 90 reduced slowing of heart rate o Ischemia highly reduced blood flow to peripheral tissues Blood preferentially shunted to brain and heart vital organs o Reduced aerobic metabolism o Increase in anaerobic metabolism in the body o Animal had no control problem Anaerobic metabolism Used with no oxygen supplies Use anaerobic pathways Produces less energy Build up of lactic acid toxic metabolite Lactic acid indicator of anaerobic metabolism can be measured in a blood sample Elsner 1960 trained animals phocids and bottlenose dolphins Range of responses dependent upon length of dive Dive response over dive reflex Dive response highly variable suite of physiological changes that a marine mammal invokes during a dive Next take it to the wild Weddell seals and elephant seals Weddell seal Large 2 5 3 meters 400 kg Antarctic distribution Never hunted found more inland than other species Gerald Kooyman colleague of Scholander Weddel seals in Antarctica Why Antarctica animals do not know to be afraid of humans so isolated from humans Weddell seals live further inland than most seals rely on access to water and air through ice holes spend a lot of their life maintaining open ice o Specialized incisors and canines to ream out ice Kooyman made an ice hole and did some experiments