The best evidence of the first postulate (or whatever you call it) would probably be from viral eovltuion. We have clear examples in moelcualr biology where both natural and artificially stressed populations change and we can even track down the genotype!
I am going to be lazy and not find the refs for you since it's your point. I personally find this undeniable evidence of both natural and artifical selection as generating inheritable changes in populations. 100 time better than the moths. There are probably some good non-mol-biol examples as well but the viral/bacterial stuff beats any other evidence I've ever seen including Galapagos.
™ Version 4.2