The inner ear contains the sensory receptors for hearing which are enclosed in a fluid filled chamber called the cochlea. The outer and middle ears purposes are only to receive and amplify sound. Those parts ofd the ear are only present in amphibians and mammals, but the inner ear is present in all vertebrates. The ear can hear in several different ways. They are volume, pitch, and tone.
Pitch is related to the frequency of the sound wave.
The volume depends on the amplitude or intensity of the sound wave. The greater the frequency, the higher the pitch. Humans can hear about 30 and 20,000 waves or cycles per second. High pitch sounds produce more of a trebly sound, while low pitch sounds produce a rumbling bass sound. When a person loses these abilities to comprehend sound, it is referred to as deafness.