New adaptations are often allowed by changes that initially better adapt a species to its old way of life.
In retrospect this can appear to be a
preadaptation to the new
adaptation but to believe that a change took place to allow a new adaptation is
putting the effect before the cause. This is not a case of preadaptation but simply
opportunism.
For example, opposable thumbs did not develop in anticipation of tool use, but in hindsight it seems very convenient, almost as though it was planned. However this was a case of taking advantage of a change and not choosing its direction.