Gibb, that is the clearest description I've heard yet of what ethnomusicology is, and how it differs from what the folklore people do. Thanks.

Like Pamela I come from a biology background, and I do have some difficulty applying the Darwinian model to temporal change in folk songs. Of Cecil Sharp's three folk song characteristics, 'continuity' and 'variation' are easily observable, but 'selection', though obviously a factor in that some songs survived and others didn't, is rather distracting because it does suggest some analogy with Natural Selection which is much more difficult to demonstrate.

FWIW, Sharp was no great fan of Darwin anyway, according to a letter of his that I once read.