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Re: Advanced Features of Birds

In a message dated 96-09-28 03:14:12 EDT, ornstn@inforamp.net (Ronald
Orenstein) writes:

> There is no reason why Archaeopteryx or any of its predecessors had
> to have been exclusively arboreal or exclusively terrestrial.

Exactly so. Arboreality includes a continuum of behaviors stretching from an
almost entirely terrestrial lifestyle with occasional forays into trees (as
in certain tree-climbing goats) to a lifestyle of nesting, food gathering,
and manifold other activities conducted with only occasional forays to the
ground (as in many modern birds and certain monkeys). But the more arboreal
the lifestyle, the more likely it is that evolution will select for
characters that improve fitness for this lifestyle, and in principle these
characters could appear in the fossil record.