Lecture 12

Lecture 12 - Magnetoreception 2 properties are typically...

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Magnetoreception 2 properties are typically manipulated - Field strength o Compass o Polarity of magnetic field of Earth Equator field lines parallel to earth Oblique to higher latitudes Near poles field lines are straight up - Angle of inclination o Map (used in this context in the field) o Can be a compass o Experiments involve manipulating virtual field lines Magnetic anomalies - These are areas where there happens to be magnetic material in the rock that nothing to do with the relationship to the Earth’s magnetic poles o In these areas a backpackers compass would spin around in a circle or show a ‘false’ north Classic Experiments: manipulating field strength - Keaton: Homing pigeons become disorientated if small magnets are attached to their head o Magnetic anomalies in the environment can also influence homing success o On overcast days pigeon got confused - Ken Lohmann: hatchinling loggerhead turtles can detect earth-strength magnetic fields o Turtles wearing a brass bar Control needed to know it’s not just the stress of the weight Orient pretty well in a predicted direction o Turtles wearing a magnet o Current in copper wire can change the field strength/direction o Angle of inclination Loggerhead turtles hatch off of the east coast of Florida Earth’s magnetic field probably helps point them away from shore when they leave the nesting ground (compass sense), accompanied by light strength They spend the next 10yrs at sea May be using magnetic cues as navigational markers at crucial geographic
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This note was uploaded on 06/21/2011 for the course NPB 102 taught by Professor Hahn during the Spring '09 term at UC Davis.

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Lecture 12 - Magnetoreception 2 properties are typically...

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