BIO 358 1st Edition Lecture 16Outline of Last Lecture !. Coloring Book Instructions II. History of Stranding research III. Type of stranding eventsA. Single strandingsB. Fishery related strandings C. Mass strandings IV. Mid-Atlantic stranding data Outline of Current Lecture I. Notes from Osteology Lab Current LectureWhat’s the purpose of a sperm whales big head? o Cushion for headbutting behavioro Produces lower frequency sound (bigger instruments make lower sounds) Premaxillary and maxillary bones carry teeth and baleen Jaw bone of odontocetes are hollow, you can see where the acoustic fat goesTop of the lower jaw presses right against the optic nerve and against the ear in a pilot whale. The bulla is right where the jaw attachesThese 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.Bulla are not attached to the skeleton – why? They have to move to give the sound directionality under waterThere are blood vessels in baleen. Baleen only comes from the top jaw. How to tell sea lions from seals by looking at the skull: sea lions have a little phalange above the eye holeto protect their eyes. Cervical vertebrae are typically more small and flexible than vertebrae further down the spine. Pinnapeds vs. Cetaceans – Really long neck in pinnipeds. They can compress their necks a lot and reach itand rotate it where as dolphins and whales can barely move their necks. Epiphysis = end of the bone (looks like a potato chip) all bones have this to protect the new bone growthThe vertebra before the fluke in a bottlenose dolphin is almost completely round which allows for rotation of that fluke. Chevrons = bones that go between vertebra and fuse them together so they become a “rod” and all of the force goes into the fluke for propulsion in the water. Ribs attach to the knobs on the vertebra. Chances are if you see a knob on a bone it means that it is connected to another bone in the skeleton. It could take 3 seconds for a nerve signal to get from the head of a blue whale to the flukes… The world is a little bit slowerManatees have a tympanic membrane that is pushed out by bones. Most ear drums are caved inwards (opposite) Vibrations in water are higher pressure with lower displacement, this is the opposite in air. Hearing in and out of water requires adjustments of the inner ear bones through the movement of muscles to change the way sound comes into the ear. The oscicles are like levers that change to adapt to the changes in sound. Massive oscicles = more inertia = sensitive hearingDirectional hearing is produced by separating the ear bones from the
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