week notes 408
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This 3 page Class Notes was uploaded by Dani on Monday March 2, 2015. The Class Notes belongs to 408 at Pennsylvania State University taught by Sheriff in Spring2015. Since its upload, it has received 52 views. For similar materials see Mammalogy in Wildlife and Fisheries Science at Pennsylvania State University.
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Date Created: 03/02/15
22715 Echolocation o The use of signals and echoes to locate or detect objects 0 Two types of signals produced 0 Clicks from nasal passage 0 Signals from larynx o 3 terms to describe a signal or click 0 Time 0 Frequency I Broadband greater than 10kHz frequency modulated FM 0 Short range but high detail I Narrowband Less than 10kHz constant frequency CF 0 Long range but poor detail 0 Intensity 0 TWO strategies of echolocation 0 Low duty cycle do not broadcast and receive signals at the same time I Emits only 20 of the time I As attack occurs time between transmission and reception shortens 0 Signal duration must drastically shorten 0 Signal rate drastically increases 39feeding buzz 0 High duty cycle produce and receive signals at the same time I Produce signals 60 of time I Use Doppler shifts in echoes to precisely track flight trajectories of prey 0 Ability to intercept prey rather than pursue prey 0 FM component allows for much more accurate location of prey 0 Problems with transmitting in air 0 Signal is attenuated quickly 0 Max range of 62 meters 0 Increasing INTENSITY of signal increases range 0 Higher frequencies decrease range attenuate faster 0 Why NOT transmit lower frequency signals 0 Higher frequencies have shorter wavelength 0 Gives more information on prey o Gives better information on directionality o Adaptation for Echolocation 0 Need to transmit signal I Oral emitter 0 Open mouths while transmitting I Nasal emitter 0 Skull is rotated to align nasal cavity with direction of flight o Mouth closed while transmitting o Nose and facial adaptations to focus beam of sound 0 Need to receive echo I Pinnae focus and amplify the sound I Tragus is responsible for vertical direction I Critical is to not make yourself deaf 0 Bones in middle ear and inner ear insulated o Neural attenuation of sounds 0 High duty cycle bats inner ear tuned to frequencies slightly above and below that of transmission species 0 Low duty cycle bats muscle adaptations inside ears tuned to own frequencies 0 Tensor tympani and stapedius do not allow signal to reach middle ear during transmission 0 Adaptations for hunting with echolocation o Echolocation and foraging 0 Open habitats I No obstacles encounter prey other bats wind borne items I Searchphase calls 0 Long duration 0 High intensity 0 Low frequency 0 Narrowband CF 0 Low duty cycles I Attack phase calls 0 Increase rate of signal 0 Increase bandwidth FM signals 0 More information I Pinnae are large and tuned to emission frequency 0 Edge habitats I Obstacles and clutter on one side open habitat on other I Search phase calls 0 Short duration 0 Intense o Broad FM and narrowband CF 0 Some bats use Doppler detection 0 CF signals 0 Able to perch and wait for prey to move into area of interception I Attack phase 0 Increase rate and bandwidth I Pinnae are tuned to emission frequency 0 Closed habitats I Forested habitat with much clutter the returning echoes of the food are often buried in a multitude of clutter echoes from leaves branches and surfaces on which the food rests I Diets include fruit nectar and terrestrial animals 0 NOT WINGED INSECTS I Search phase calls 0 Very short 0 Broadband o Steep FM calls 0 Low intensity I Food location 0 Olfaction o Prey generated sounds rustling on ground mating calls etc o Echolocation is primarily used IN ABOVE GROUND SPECIES to perceive surroundings Echolocation in Cetaceans 0 Used by all odontocetes toothed whales and dolphins 0 Two types of signals 0 Narrowband whistles used to communicate 0 Broadband clicks for echolocation o Clicks are generated in nasal passage 0 Sounds then propagated forward through the melon on top of nosemouth o Incoming sounds Reception of sounds in middle and inner ear Bullae is not fused with the skull Bullae are insulated with system of oilmucusfoamedwithair filled sinuses 000 This allows proper sound reflecting while under water and at depth
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