This article is a discussion of the common characteristics of jazz and how defining these common characteristics have become increasingly more difficult as the genre evolves.
Time Frame
As a result of the evolution of the jazz genre, to define exactly what qualifies as "Jazz" at any given point in history is absurd because it has never been one single form of music.
History
Early jazz before the 1930s is defined by ragtime and big bands. The Great Depression brought on smaller bands, known as the bebop era, which led to the development of the smaller groups seen in rock and roll and most modern genres.
Identifying Features
The common characteristics of Jazz over the history of its evolution are defined by syncopation, off-beat rhythm and improvisation, among other qualities.
Fun Fact
The radical difference of early jazz from classical music made it quite frightening to the many people of the time, much in the way that rap and metal genres may be considered today.
Speculation
Many musicologists have speculated that jazz is a dying breed of music because of the declining popularity of the music of the wwing and bebop eras. Others, however, speculate that jazz isn't dead, but has simply evolved (rock and roll or rap for example), which are surely not dead or dying.
