I'm well out of my depth here but I'd like to just mention Schroedinger's 'faux-Lamarckism' of which I'm a fan. 'Use it or lose it' seems to sum it up. The mutations may be 'random' but their survival would be behaviourally determined. He proposes that our ability to walk is the result of our wanting to walk, not simply the result of our being given the tools to do so. I'm not sure if this adds anything to the discussion.   

He also says some interesting things about genetic mutations, pointing out that the locus of the mutation is too confined for the statistical laws of physics to apply. I've never heard another physcist comment on this and wonder whether he's right.