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Re: Audobon bird/dino article



Betty Cunningham wrote:
> 2) He includes animals in his arguments against a close bird/dino
> relationship that we HAVE NO FOSSIL EVIDENCE FOR as gospel scientific
> proof for an argument.
>             "Well, any engineer will tell you that's aerodynamically
> impossible.  In every group of 
>              animals that flies or glides-BATS, frogs, snakes,
> squirrels-it's evolved from the trees down."
> a)What possible evidence does he have for bat origins?  Everything we
> have that's been identified as a fossil bat is because it has batwings
> and already flies.  WE HAVE NO FOSSIL RECORD FOR WHERE BATS COME FROM AT
> ALL.

It is correct that no fossils are known that tell us about the 
beginnings of flight in bats. However, I suppose that in this case it 
is highly probable that flying started as some kind of gliding in the 
trees. There is another group of living mammals (the order 
Dermoptera with the East Asian genus Cynocephalus) that is still in 
this evolutionary stage of gliding, with no active flight. These 
animals have even been considered as close relatives of bats. There 
is no other way of starting something like flight in early bats that 
I could imagine. 

However, birds / dinosaurs represent a wholly different case:
Bipedal dinosaurs could have attained the necessary speed for taking off 
by running, especially dinosaurs as well adapted for running as 
dromaeosaurs. Comparable potential (bipedal) ancestors are highly 
improbable for bats (as well as frogs, snakes ... ), so it makes 
little sense to compare  birds with these groups.

Martin Jehle, Dipl.-Ing. (FH)
martin.jehle@klinik.uni-regensburg.de
Regensburg, Germany