Latin jazz uses familiar percussion instruments including congo and other hand drums as well as an assertive horn section. African-influenced jazz may be heavily percussion-driven or may alternatively rely strongly on choral vocals. European jazz musicians have also transformed the art of jazz by using innovative, experimental sounds and improvisational tools. Jazz is a musical genre that is ever-changing, and yet remains driven by its roots. Jazz may be either instrumental or vocal-driven. In the early years of jazz, vocals often featured sultry female voices such as that of Sarah Vaughan. Other vocalists like Louis Armstrong have also made indelible marks on the jazz genre. While jazz vocals are often watered-down today as in the case of Diana Krall, some artists like Tom Waits offer audiences rich and emotional experiences that hearken to the heyday of jazz music. Instrumental jazz can be every bit as exciting as vocal-driven jazz. Instruments like the trumpet can in fact serve the same role as the human voice. Likewise, the human voice is sometimes employed like an instrument in jazz music as with scat singing. Scat, made most famous by Ella Fitzgerald, uses the human voice to mimic instruments. Instead of being powered by lyrics, the voice becomes an instrument in itself. The range of the human voice used in jazz is unlike that in...

The opposite of big band, minimalist jazz relies on as few instruments and notes as possible while still retaining some semblance of melody and rhythm. A strategic pluck of a bass string or trumpet bellow can be every bit as effective as a steady bass line or trumpet solo. Jazz is nothing if it is not innovative.
Jazz stands apart from other musical genres in its tremendous flexibility and adaptability. Whereas most genres of music are distinguishable by certain key elements such as time signature or instrumentation, jazz is almost by definition undefinable. Jazz does, however, boast several sub-genres including ragtime, big band, free jazz, and acid jazz. Jazz can have a steady rhythm from a loyal bassist and drummer just as in rock music. On the other hand, jazz can be utterly free-form in a way that rock music cannot without transforming itself into something that is no longer rock and roll. Therefore, jazz encapsulates the artistry of creative music. It is one of the most dynamic and universal forms of music, open to incorporating elements from global instrumentation and song structure.

Reference

A Passion for Jazz (n.d.). Jazz Timeline. Retrieved June 5, 2010 from http://www.apassion4jazz.net/timeline.html