It depends on what you mean by random. Would you call having you grandfather's blue eyes "random?" My point is that the mutation does not have to be to a new thing. It can be an emergence of an older pattern within the genome.

You are right. It is not LITERALLY not "calling upon" because the effect is over generations and comes about through waves of individuals with one trait outbreeding another but the net effect is that a change in environment brings about changes in the population over time.

I was speaking figuratively for those who may not have the model and mathematics of natural selection firmly planted in their heads.

The fact that some people have webbed toes is not a random mutation. It is an occasional manifestation of a trait that is contained in the human genome.