Re: Fwd: Gliders to Fliers? (Was Re: Ruben Strikes Back)

[Stanley Friesen <sarima@ix.netcom.com>]

At 09:50 PM 9/24/99 -0400, Dinogeorge@aol.com wrote:
>mammals (humans, kangaroos). Climbing up a vertical substrate gives the fore 
>and hind limbs different functions (the forelimbs pull while the hind limbs 
>push, for example), which readily promotes decoupling of the limbs for their 
>different functions.

I suspect that this, by itself, is why humans are bipedal, and *maybe*
kangaroos as well (there *are* tree kangaroos after all).  That is, I
suspect that this sort of tree-climbing decouples the limbs, and promotes a
tendency towards bipedal locomotion on the ground.  Flight, or even
gliding, is not really necessary to achieve this result.

It is quite possible that the ancestral dinosaur (or at least theropod) was
scansorial or arboreal, and all of its descendents are bipedal as a side
effect. 

[On the other hand, prosauropods seem to be semi-bipedal to promote feeding
access to trees].

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May the peace of God be with you.         sarima@ix.netcom.com