Title Author Date

Coutler and bird evolution Ichneumon Jul 27, 2006

DAMN that was good... And so are your installments #1 and #2. I eagerly await the rest.

A couple of trivial comments...

You write:
"These earliest birds were quite small, and illustrate some deeper implications for avian biology and ancestry: they could only fly by trading off the energy their theropod cousins had devoted directly to growth, Schweitzer & Marshall (2001, 323-325)."

I haven't read the cited paper, but I can think of some other factors driving the small size of the early birds beyond "trading off on the energy" devoted to growth. The first is that an early imperfect flier would obviously be more effective at remaining aloft (and/or surviving crashes) at a lighter weight (and thus smaller body size). The second is after hatching that modern birds "grow into" their feathers at an incredible rate -- I've raised parrots and even the largest species are full-grown in mere weeks. The necessity for this growth spurt appears to be related to "growing into their feathers", since even their first "coat" of feathers are full-sized. If their bodies didn't achieve full size quickly, the young bird would have a hard time flying with full-grown feathers (and conversely, if they grew a set of "baby feathers" first, their growing bodies would eventually leave them with undersized feathers until the next full moult, also an impediment to flight). So the evolved solution is to sprout full-sized feathers from the start, and grow into them as soon as possible. All of this is less of a make-or-break issue for a small-bodied bird, however, and I can envision that the early birds, before the "grow like a weed" process was made available, got around the feather/body match problem by reducing their overall size.

Near the end of your piece you remark on how "It took many pages to explain why Coulter's single paragraph was wrong." I call this the "demonstrating what huge volumes of scientific evidence the creationists left out of their cartoon versions" effect. It takes very little space to say something false. It takes a lot more to tell the truth, the whole truth, and nothing but the truth, and to document and support the validity of it.

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