Hello Squeezy. Funnily enough I was trained in Evolutionary Biology as well (Richard Dawkins, no less, was one of my lecturers!) and the analogy you make is one I've often considered myself. As is the similarities between the fossil record and the patchy nature of folk song collection.

However I have to quarrel with both you and George about the "religious observance of old styles of interpretation". Several people in the folk revival who I admired made a point, early in my singing career, of opening my ears to the early recordings of traditional singing, but I don't remember anyone ever saying that these were "the right way to go about things". Rather, they were worth listening to in their own right, while at the same time offering stylistic points that could be learned from, as opposed to slavishly copied. No-one was a greater proseletyser for studying traditional recordings than Peter Bellamy, yet his own style was entirely individualistic - mainly because he absorbed all kinds of different influences, including blues and Appalachian balladry, alongside Sam Larner and Harry Cox, and mixed them all up with a large chunk of rock'n'roll attitude and his own flamboyant personality.

It's true that constant referral to recordings from the first seventy or so years of the twentieth century, as if they represented the definition of traditional style rather than merely a random snapshot of it, could conceivably interfere with the normal process of musical evolution. On the other hand, that process is being accelerated at an almost exponential rate by advances in communication, and gently applying the brakes from time to time isn't going to stop the runaway. Compare a recording made of Joseph Taylor in the 1900s with one of Fred Jordan in the 1950s and one of pretty well any English singer you care to name in 2000, and I'd suggest that there's been a qualitative stylistic change over the later period not evident in the former.

Personally I think music is more interesting when it's a bit weird than when it's bland, and if a few of those archaic stylistic features help to differentiate our music from the mainstream, that's no bad thing.