Sunday, March 19, 2006
Coming Soon: Evolution of the Lateral Line into the Ear
On Monday I posted this Nature news item to the General Evolution News category:
"Why is our cochlea, the key organ of hearing, curled into a spiral? It has been often thought to be a space-saving measure. But researchers in the United States have shown that the spiral could be vital for increasing our ear's sensitivity to sound, particularly at low frequencies.
Daphne Manoussaki of Vanderbilt University in Nashville, Tennessee, and her colleagues believe that the snail-shell curve of the cochlea focuses sound waves at the spiral's outer edge, making it easier for vibration-sensitive cells to detect them1.
If the researchers are right, then the ear is more sophisticated than we thought. "
Not only is the article interesting in itself, but it brought to mind something I read sometime ago concerning evolution of the lateral line into the ear, and I thought it might make a good example of how such questions can be approached from the perspective of the proposed internal evolutionary mechanism.
I've spent quite a lot of time today trying to establish a 'baseline' from which to proceed, making sure I've got my facts right etc., but it may be that the notes will be very brief. It's a question of starting from the 'top' and then deciding how far down the hierarchy to go - I'll probably spend more time on creating the jpegs! Anyway, the post should give an insight and hopefully will be ready by Wednesday at the latest.