Vestigial structures in biology are commonly cited as evidence for evolution, and it may well be that they did evolve. But if it is evidence of evolution, it is evolution in the wrong direction — it’s not the sort of function enhancing/innovating evolution that is supposed to give evolutionary theory its bite. Vestigial structures, after all, are structures that have lost their function. If all of evolution proceeded in this fashion, we’d quickly descend to a world of nonfunctionality.
But vestigiality need not evolve by purely material means — it can also be designed. I was delighted to be informed (after my recent debate with Michael Shermer at Bridgewater College) of a nifty example of vestigial structures that arise not through “devolution” but rather through design, to wit, vestigial running boards on older automobiles. Look at the following Ford models:
1947 Ford (vestigial running board)
1941 Ford (vestigial running board)
1940 Ford (functional though abbreviated running board)
1928 – 1930 Ford A’s (the real deal — a big running board with room to stand on and even tie things down to it)