Re: Re-emergence of lost features.

["John V Jackson" <jjackson@interalpha.co.uk>]

-----Original Message--From: Betty Date: 16 March 1998 07:41


>> John V Jackson wrote:
>> I suspect two barriers to re-evolving good hands: In flying forms,
>> developing clawed hands and fingers would tend add weight and spoil
>> the aerodynamic properties before they lent any other advantage.

>of all flying vertebrates, birds are the only ones that do not have
>clawed fingers on their hands-both bats and pterosaurs do (or did).


Yes.   I suppose that's because birds are bipeds and the others are oblig.
quad.s.

Trees became more perchable and flying abilities and other factors made it
less essential to cling to vertical surfaces, and perhaps birds lost their
claws that way.

I suppose you were referring also to the presumed aerodynamic acceptability
of claws, which is true enough.

JJ