Leeneia >I would call it the opposite of tune evolution.<
No, it's the opposite of "improvement"; but evolution (biological, musical or any other) can go in any direction. For example some breeds of dogs that have evolved by artifical selection can have serious anatomical problems. They have evolved to be best fitted for the show ring and ill fitted for an ordinary life.

Can Gibb please come back and explain
a) how the ethnomusicologists on the 50s understood and used "evolution" and
b) what the present generation use instead?