There was an interesting discussion started by RAZD on another thread here:
EvC Forum: How do "novel" features evolve?
about the evolution of novel features, but it got sidetracked by technical discussions about information theory and died an early death in summation mode.
There seemed to be some support for having another attempt at it but without getting into entropy, thermodynamics, information theory or other exotica. ie, let's stick to biology, and the simpler the better (for me at least.)
I think that if we could answer this challenge in an easily understandable way we could make some progress.
"I accept that natural selection does occur and that it can cause a population to change, but you need now to show me how the genome created those novel features because, until you do, I can say that the genome must have had them to start with."
My example was peppered moth observations that show selection for a trait can and does occur but doesn't answer the question about how the trait arose in the first place so that it could then be selected for.
The creationist could argue that the genome carries a complete set of genes that can be selected for when necessary. The biologist even has a name for this - it's called gene plasticity and in the example of the Italian Wall Lizard the claim that the novel feature evolved there - the cecal valve - could simply be an example of that.
So how do we progress from here?
Life, don't talk to me about life - Marvin the Paranoid Android