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Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
----- Original Message -----
From: "Michael Habib" <email@example.com>
Sent: Friday, September 26, 2008 9:32 AM
Subject: Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
I'm not sure I'd frame a separation between gravity
and muscle power usage, however. Even in those groups where arboreal
stages have been critical to the origin of flight, it is quite likely
that powered leaps were involved - there is no reason to assume that
flight evolution needs to be begin with simple falls (especially for a
group such as birds, which inherited a strong leaping apparatus). This
is yet another reason why setting a threshold between arboreal and
terrestrial origins is difficult and misleading - both may actually
involve very similar launch dynamics.
This is very similar to my own thinking.
Granted, but if the evolution of powered flight in a given group
involves movement between the ground and trees, or involves an intense
mosaic of both arboreal and terrestrial forms, then we will probably
never have the resolution required to pin down the ecology of the
"first" ancestor in the sequence. And besides, if that "first step"
happens to be populations that use both trees and ground running, then
the dichotomy is really broken.
And that as well.