Evolution of the cochlea of the ear, consisting of the scala media, the scala tympani, and the scala vestibuli. Regarding mammals, placental and marsupial cochleae have similar cochlear responses to auditory stimulation as well as DC resting potentials. This leads to the investigation of the relationship between these therian mammals and researching their ancestral species to trace the origin of the cochlea. This spiral-shaped cochlea that is in both marsupial and placental mammals is traced back to approximately 120 million years ago. The development of the most basic basilar papilla (the auditory organ that later evolved into the Organ of Corti in mammals) happened
Evolution of the cochlea mammals. Prestins are located in the outer hair cells of mammalian cochlea and are considered motor proteins. They are found in the hair cells of all vertebrates, including fish, but are thought to have initially been membrane transporter molecules. A high concentration of prestins are found only in the lateral membranes of therian outer hair cells (there is uncertainty with regard to concentrations in monotremes). This high concentration is not found in inner hair cells, and is also lacking in all hair cell types of non-mammals. Prestin also has a role in motility, which evolved a greater importance in the