[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

re(2): Progress in evolution (archie growth)



     (this bounced when our server at work went down,  so I'm trying again)
     
     Exceeded maximum number of retries when attempting to send message
     Original text follows
     ------------------------------------------- From bcunning@nssi.com 
     Subject: Re[2]: Progress in evolution and the origin of flight feathe
     
     
     >A strong wing flap, directed forward and downward, is also the >power 
     >stroke that gives lift to a bird in takeoff. Lipps and I >suggest 
     >that strong wing flapping is a simple extension of display >flapping, 
     >encouraged by fighting behavior. Powerful flapping used >to deliver 
     >forearm smashes could have lifted the bird off the >ground, allowing 
     >it also to rake its opponent from above with its >hind claws. The 
     >more rapidly the wings could be lifted for another >blow, the more 
     >effective the fighting. This would rapidly encourage >an effective 
     >wing-lifting motion that minimized air resistance, so >the wing 
     >action would then be almost identical to a takeoff stroke.
     
     Geese (domestic and otherwise) attack with their wings from the 
     ground without taking off.  It's probably due to the size of the bird. 
      Trumpeter swans also deliver quite a klonk with their wings without 
     any elevation.  Neither tends to use their feet at all during an 
     attack.  They both have enough height that when attacking something 
     human-sized they don't display (sorry) to a disadvantage. Most 
     possible bird ancestors (sorry George) would seem to be more of 
     geese/swan size than smaller.  (or conversly, bird-sister taxons that 
     existed within Dinosauria would generally prove to be larger or same 
     size than Archie)
     
     >Selection has favored fighting ability over flying ability for many 
     >steamer ducks. Flight is perhaps less important for them than for 
     >many birds, because they live in shoreline habitats where food is 
     >plentiful all year round.
     
        Geese and swans both live in shoreline habitats.  However both are 
     much larger than any size estimate for Archie.  Does the possible 
     continuing growth of dinosaurs (as suggested by some) have any 
     evidence in growth-size in Archies? 
        If he did fly, he couldn't have grown beyond a certain size, 
     right? Bird species can get too big to fly, but it takes much weird 
     manipulation by Man to get a flying-type bird to a size that it is no 
     longer capable of flight.  (like 4 ft tall chickens)
        Would this have been built in to his growth-rates before or after 
     archie-types took to the skies?   I suspect a size-limiting factor 
     would have had to have been present before the creature could have 
     evolved flight.  I don't think it could have happened as a trait to 
     aid flight, but would have had to have been present first.  Right?  So 
     wouldn't that mean that his sister/parent groups probably had the 
     size-limiting factor as well?
     Am I on to something?
     
     -Betty Cunningham