Our ears are in actuality a complex mechanical device. Many other processes like sense and smell have chemical reactions involved. However, our ears are completely mechanical in process. For a complete and simple step by step process on how our ears work, please check out How Stuff Works. They have a great explanation of the various mechanical processes involved in hearing.
Have you ever wondered if something was beyond your control or felt like you were inclined to do it? Sure you have, but the logical thought process is that is just an excuse. However, maybe not, while its unlikely we will be able to start blaming all of our behaviors and actions on our genes it is becoming clearer that our behaviors may be the result of our genes. Scientists have unraveled many of the links between our genes and physical traits. However, behaviors and what drives people are more subjective and harded to quantify.