Short answers, pulled from the story.
Jazz originated in the African-American communities of New Orleans, Louisiana, in the late 19th and early 20th centuries. Its roots lie in blues, ragtime, European harmony, African rhythmic rituals, spirituals, hymns, marches, vaudeville song and dance music.
The word jazz is believed to be related to jasm, a slang term dating to 1860. Its earliest written record is a 1912 Los Angeles Times article where a minor league pitcher described a 'jazz ball', and the American Dialect Society named it the Word of the 20th Century.
Jazz is characterized by swing and blue notes, complex chords, call and response vocals, polyrhythms and improvisation. Improvisation is considered its defining element, since the jazz performer interprets a tune in individual ways and never plays the same composition twice.
The Spanish tinge is the name Jelly Roll Morton gave to the tresillo and habanera rhythm, which he considered an essential ingredient of jazz. He said that without putting tinges of Spanish in your tunes you would never get the right seasoning for jazz.
In the early 1940s, bebop shifted jazz from danceable popular music toward a more challenging musician's music played at faster tempos with chord-based improvisation. Its most influential figures included Charlie Parker, Bud Powell, Thelonious Monk, Dizzy Gillespie, Clifford Brown and Max Roach.
Miles Davis's Kind of Blue, released in 1959, became the best selling jazz album of all time. It introduced modal jazz to the wider jazz world, composed as a series of modal sketches in which musicians were given scales that defined their improvisation.