“somebody played a wrong note …… and jazz was born”
We can find many metaphors from the natural world with which to compare the creation and development of musical styles. A tree (or a river), with its multiple branches is quite good, but the concept of evolution is even better.
When Scott Joplin, Afro-American composer and pianist, created his new “Ragtime” musical style in the early 1900s, little could he know that this tiny new branch that he had placed on the tree of music would later not only grow into a huge and beautiful tree but would also multiply and diversify, creating ultimately a whole new tropical forest: the magnificent musical world of 20th-century popular music. Joplin’s fusion of dancing African folk rhythms and classical harmony ultimately gave rise to jazz, rock, pop, and all their multiple offshoots and variants, which are like new species that developed from a common ancestor. We can thank the Afro-American culture not just for jazz, but for the whole kaleidoscopic forest.
The fundamental musical “mutation” that allowed jazz to develop was rhythmic, most notably syncopation, and this “loosening up” of rhythms was matched by a parallel loosening up of harmony.