When you hear some music you like, thank a fish!
About 500,000,000 years ago fish began to develop the ability to sense vibrations, but not with anything we would call a ear.
Improving on the fish system, amphibians developed sack-like organs containing clumps of neurons
devoted only to sensing vibrations, much like the ears frogs have today. Birds improved the design even further.
The ear reached its peak with mammals and the appearance of the pinna, the fleshy outer ear which funnels sound to the cochlea -- one of the many tiny pieces of the inner ear. The cochlea takes sound vibrations, transduces them into nerve impulses and sends them to the brain.
It took over one hundred million generations of creatures to evolve a ear capable of hearing music. With this wonderful ability to hear, it’s no surprise that we humans began to organize sounds into patterns of rhythm and pitch. That’s music!