In reply to:

why quavers? quaver... "a note, equal in length to half a crotchet or one-eighth of a semibreve." but wait. let's give jazzo a chance to tell the story....

since jazzo ducked the chance to piffle this, I will tell you that a quaver is so-called because of the way it was originally sounded, with a tremble or quiver (i.e., the verb quaver was nouned!)