Pamela said
> Given that the course is being offered in the Music department, however, I feel I should have at least some examples in which we examine the evolution of *tunes

Do you want to do this for song tunes, dance tunes, "listening" tunes or all of those?

Julia Bishop has done some work on song tunes, including the tricky issue of how one might decide whether two specimens are different tunes or different versions of the same tune.