[continued from previous message]   
      
   >> reverse" would be essentially impossible, as you say there   
   >> are multiple paths. All that would be required would be a   
   >> re-creation of function, not an exact "reboot".   
   >>   
   >> As has been pointed out several times, a re-start at the   
   >> original point would almost certainly (probability as close   
   >> to zero as can be imagined) *not* follow the identical path   
   >> resulting in the current species, but the same challenges   
   >> should result in something similar.   
   >   
   >   
   > By analogy, it's possible flightless birds could potentially re-evolve   
   > functional flight, but the newly evolved structures would necessarily   
   > be very different from those of extant flying birds.   
   >   
      
   flightless birds still have feathers, but they are more like the   
   feathers dinos had in some cases.  In a lot of cases the wing feathers   
   do not develop properly and are too short or the bird is now too heavy   
   to fly.  You would not have to reevolve flight feathers, just redevelop   
   flight functional feathers, and you would not have to do it by   
   recreating what got broken, you could do it by taking a path similar to   
   the one taken by dinos to evolve the flight capable feathers in the   
   first place, but you already have flight feathers.  My take is that if   
   the flighted birds went extinct that even ratites could reevolve flight   
   using feathers, but they would have to reevolve the feather structure   
   needed for flight.  They still have the basic capability, they just need   
   to improve it like dinos did.  They would not have to do it in exactly   
   the same way that dinos did it.  They all still have keels, as far as I   
   know, so they would not have to reevolve that structure for flight   
   muscle attachment.   
      
   Ron Okimoto   
      
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