Hello everyone.
More on Wayne's original topic! Admittedly, I hadn't read much about this before, although it is interesting.
More on Wayne's original topic! Admittedly, I hadn't read much about this before, although it is interesting.
In the recent BIOL1040 Biohorizons eConference assessment event, we were tasked with asking questions of the other student responses in our area. My group's area was diversity and adaptations in sensory biology. One of the groups I asked a question of had researched microchiroptera, those bats which generally hunt insects with echolocation (also known as microbats). They have other anatomical differences to megabats (fruitbats etc., of which only one uses echolocation), but their main feature is echolocation. The papers the group used to create their response were investigating the possible use of echolocation abilities as a means of communication. The hypothesis was that microbats use and are sensitive only to very specific ranges of frequencies, and that they either diversified from one echolocating frequency or echolocation arose separately in several lineages/was lost in some and re-emerged. I thought that an interesting biophysical question is how sensitive a species can be to certain frequencies. It is my understanding that the current evidence suggests a strong bias in the brain to acknowledge only certain frequencies, but how is this enacted physically? Also, how specific can the frequency production and reception be, if we consider fundamental physical limits? Afterall, most microbats are of similar size and evolutionary background, so one would expect great similarities in their hearing and vocalising organs.
Josh H
I would suggest that the frequency dependence is more a property of the stereocylia themselves, rather than the gross structure of the auditory organs themselves. After all, the bat has to achieve excellent temporal resolution of sound in order to echolocate, so it would be sensible if the cochlea was set up so that it quickly damped out any sound. Maybe we could combine these ideas and hypothesise that the low-frequency receptors are far from the point of mechanical stimulation of the cochlea?
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