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

Re: Modern Bipeds [was re: Biped advantage]



In a message dated 96-11-17 03:07:30 EST, znc14@ttacs1.ttu.edu (Jonathan R.
Wagner) writes:

<<  4) Birds:  Are decendants of bipedal ancestors, and, unless you
 choose to a priori assume George's "BCF" theory is correct, were bipedal
 before developing flight.  This does not, however enlighten us as to whether
 bipedalism evolved from an arboreal condition.  Shucks. >>

Just a quick point here: In BCF, bipedality evolved >along with< arboreality
and the development of the forelimb into a wing in the lineage leading to
birds. The flightless, cursorial descendants (i.e., various theropod groups)
that diverged from this lineage retained whatever bipedality they had already
evolved in the trees and >developed it further< as part of their increasingly
cursorial lifestyles. So: they were most likely not bipedal before going up
into the trees (they were either sprawlers or semi-erect when they became
arboreal); but those that came back down out of the trees were.