Book Review- Shipman, Pat. 1998. _Taking Wing: Archeopteryx and the Evolution
of Flight_. Simon & Schuster, NY.

_Taking Wing_ is an exploration into the debate about the origins of birds
and the singularly unique avian solution to powered flight. The debate is
an old one- are birds dinosaurs? or are they from a reptilian line that runs
parallel to them? Did birds evolve flight by falling out of the trees?
or did they jump up from the ground? The debate is technical, academic and
often acrimonious. It is also largely hypothetical.

Shipman, an anthropologist, proves unable to tackle the task of sorting
through all the rancor objectively. Her style is ponderous and filled with
digressions. She claims to be presenting all sides of the issue involved,
but her tone changes when she confronts ideas that run contrary to her
biases. She wears her prejudices for a ground up, dinosaurian model on her
sleeve.

Shipman eventually presents enough real detail and evidence to bring the
reader around comfortably to the notion of a dinosaur origin of birds. The
accumulated proofs of comparative anatomy are hard to argue against, when
there is no comparable alternative among the non-dinosaur choices.

But if one uses the same criteria for judging a ground up hypothesis for
the development of powered flight in birds, there is only hypothesis and
no comparative proof. Shipman spends much time explaining away all of the
comparative tree down evidence among living species in all terrestrial
vertebrate classes, then tries to build a case out of thin air for the
ground up hypothesis (for which there are no modern examples). The case
hinges on the similarities between cursorial dinosaurs and _Archeopteryx_,
but if having wings somehow enhances a cursorial lifestyle, why do most
cursors not use their wings when running today?

There is simply not yet enough evidence to reach any kind of satisfactory
conclusion about the development of flight in birds. It also seem unlikely
that there will ever be adequate fossil evidence for supporting a tree down
hypothesis, because bird-sized fossils don't typically form in forests.
Basing any arguement about evolution on a single species is dicey
and Shipman doesn't even come close in _Taking Wing_.

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* Mike Patterson, Astoria, OR * 2000 mockingbirds = 2 kilomockingbirds
* mpatters at orednet.org *
http://www.pacifier.com/~mpatters