Re: Bird flight once more (was Re: What is a Dinosaur? and semilunate carpal)

["David Marjanovic" <david.marjanovic@gmx.at>]

> << Wings can
>  easily have evolved (on an already feathered animal, contra BAND) for
>  brooding -- and here marginally longer feathers _in the exact right
places_
>  mean marginally more room for eggs means directly more offspring. It can
>  hardly become more Darwinian. >>
>
> And how does, e.g., a stiffened tail help the animal with brooding
feathers
> on its forelimbs?

Not at all, of course. This is certainly for balancing as proposed long ago.

> And how does a distally articulated hallux help the animal
> with brooding feathers on its forelimbs?

Also not at all. BTW, *Archaeopteryx*, *Microraptor* etc. don't have this,
this feature is peculiar to Pygostylia and really an arboreal feature
IMHO -- evolved after birds were able to fly up into a tree.

> And how do stiffened forelimbs help
> an animal with brooding feathers in its wings?

They are no hindrance, and they apparently help for certain predatory
actions.

> And where does small size fit into this mishmash?

Small size can evolve for lots of reasons. I don't think I have to choose
one here. The evolutionary process I described can only happen at small size
AFAIK (e. g. brooding and living like a dipper becomes difficult at and
above *Compsognathus* size).

> It is not just the characters that are acquired, it is
> also the order in which they are acquired that needs to be accounted for.
BCF
> accounts for this as well as for the characters themselves.

So do the hypotheses I use.

> Dinosaurs acquire character A for this reason, B for that reason,
characters
> C, D, E, F, and G for various other reasons, and suddenly we have a flying
> BIRD!

Yes! :-)
I _REALLY_ think this is how "macroevolution" works in general. The Conquest
of Dry Land -- lungs for one reason in water (probably to enhance
endurance), loss of gills for another, digits for another, strong shoulders
and a neck for others again, and suddenly you have a tetrapod walking on
land.
        All we have to do is to find consistent hypotheses for the evolution
of each character that can apply in the right order, and find out that right
order.