PHYLOGENETIC DEVELOPMENT OF THE COCHLEA AND ITS INNERVATION

Comparative studies of vertebrate hearing organs have enabled an integ rated approach to difficult questions related to function. Recent evid ence for the independent evolution of similar hearing-organ specializa tions, in particular hair-cell differentiation, has helped identify co mmon problems of hearing receptors and put them in a new perspective. Evidence that cochlear amplification is an ancient phenomenon has wide ned the search for the motor mechanism involved. In this regard, diffe rent hypotheses are best examined by making optimal use of natural str uctural variations. Studies on the evolution of the efferent system ha ve provided new routes to investigate its function.