Wings and evolution

[gj student 169883]

  I have a question regarding the evolution of any species with
specialized members that would require many generations to serve a
useful purpose.  A specific example is that of wings: clearly, for the
first n generations, the "ancestors" of wings would not be
evolutionarily adaptive but would rather be a hinderance until they
became flight-able.  I wonder, then, what mechanisms can be used to
explain members such as these.

  If you know of anyone who might be able to help me with this
question I'd appreciate being put in touch.

  Thanks for your help.

  Colin Rowat
  Department of Psychology
  Carleton University.