BIOL 4041 Lecture Notes - Lecture 18: Sound Localization, Tracheal Tube, Induction Coil
Document Summary
Transient: onset disparity between r and l ears. Ongoing: continuous disparity between r and l ears. The owls use the ongoing disparity to differentiate! A difference in 42us for every 20 degree change in azimuth. Tympanum is a membrane that separates an air pocket from the outside world. If there is a pressure difference across the membrane, the tympanum will allow air to pass in order to come to equilibrium. Frogs and crickets: tympanum connects to tracheal tube which allows passageway to be continuous. Grasshoppers and cicadas: air sac spans across abdomen. Birds: instantly compares pressures across ears; interaural canal. Activation of neuron comes from longitudinal stretching of cilium. Too small to detect differences in time or loudness across body: most insects are sensitive to 30-60khz, almost all insects have 2 ears located far apart on the body. So they can tell where sound is coming from. Acoustic communication is an important part of insect lives.
