[continued from previous message]   
      
   >>> 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   
      
      
   Alternately, descendants of extant flightless birds for example could   
   evolve skin between their legs, along with feathers attached to that   
   skin, to create an entirely different airfoil. That would be a new   
   path that affirms Dollo's Law.   
      
      
   >As things stand right now, whales/dolphins would stand little chance of    
   >coming back on land unless there were some new, unoccupied ecological    
   >niche that didn't have something there already.  But consider a major    
   >extinction event that wiped out most land vertebrates;  there'd be a    
   >free-for-all, and it's hard to rule out anything.   
      
      
   Some orca and porpoise are known to practice a technique where they   
   surf through shallow water to temporarily beach themselves, to reach   
   shallow water fish, sea mammals, and penguins.  Such behavior could   
   make advantageous any adaptations to improve that technique.  This   
   could be one pathway for them to become more terrestrial, without   
   having to wait for an extinction event.   
      
   --    
   To know less than we don't know is the nature of most knowledge   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)