I thought it was, perhaps, time to take a look at this subject again after reading a post by romajc in another thread.
Beneficial mutations - traditionally creationists assert that they do not occur, as far as I'm aware. Their position is that all mutations are harmful and adversely affect a creature's survivability, or neutral and do nothing - part of the notion that creatures are "degrading" since the Fall of Man, and cannot be improved as such.
Of course, evolution is simply a compilation of many, many beneficial mutations which, after a very long time, alter a creature to the extent that we may classify it as a seperate species. One single mutation may be very minor, but it is the sum of all the mutations that makes evolution - little steps along a path adding up to miles and miles travelled, if you will - and there is no concieveable limit to it as long as we can show that beneficial mutations occur constantly.
So - it may be beneficial (
) to creationists if we list some simple examples of such mutations, and explain why they are so and why they will be passed to the next generation.
My example: My mother is missing four molars, so she has only one set per jaw instead of two. I have inherited this mutation, and I am missing two wisdom teeth as well. It is beneficial because my teeth are very easy to clean, hence my teeth are very healthy and I have no fillings or anything. It has not effected my ability to eat at all.
Assume for a minute that I am a prehistoric human. As my teeth are very healthy due to my mutations, I will retain them longer than someone without those mutations - so I can eat better for longer than them and will probably live longer as a result. Let's assume as well that my tribe find teeth aesthetically pleasing in a mate - I am more likely to find a mate than someone toothless. Both these environmental conditions will give me a higher chance to reproduce and pass on my mutations.
In modern times those conditions are absent, so my chance to reproduce is not affected per se. But having healthy teeth is a nice bonus. Bear in mind that this is an illustrative example and probably isn't entirely accurate, but it does describe how beneficial mutations are selected for and passed on.