On 5/25/2012 6:36 PM, Jason Brougham wrote:
In a hypothetical, strictly ground - up, ancestor of Avialae, wouldn't we expect the feet and legs to completely retain their ancestral form? Only when we get to powered flight will the little dickens' be able to drop down onto trees, and only then can they start adapting to branch gripping.
That seems about as certain as anything...I argue that the inverse does not hold, though -- a strict tree-down scenario would not logically (at least in the 'tree-roosting, ground-foraging' case) result in a perching or climbing pes prior to the evolution of full-on flight.