Page 105 - The Origin of Birds and Flight

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THE DETAILS OF FEATHERS
Open penna-
ceous wing
feather
Small
hook
Cavity
Wing
feather Open pennaceous wing feather
Barbules
Main feather
stems
Kapal› pennaceous
Barb tüy kanad›
Feather
stalk
Stem
Closed pennaceous wing feather
Pennaceous feathers
Plumulaceous (soft) feathers
The structure of various bird feathers is too complex to be explained
by any coincidental process. In the middle of the feather is a long,
hard tube that constitutes the stalk. Hundreds of hairs protrude from
either side of it and with their different lengths and softness, give the Plumulaceous (soft) feathers
feather an aerodynamic property.
Even more surprisingly, is the way that each of these has still smaller
hairs on it. Known as barbules, they are too small to be seen with the
naked eye. On these are miniature grippers, known as hooks.

is greater than on the upper, a force that will lift the plane is created and the
plane takes off. In birds, the flight feathers are asymmetrical in order to
achieve this same effect. In addition, smaller feathers in the wing’s front
edge are in direct contact with the air.
The complex aerodynamic principles in the avian wing also include a
mechanism that reduces the negative effects of air pockets and down-
drafts, the main cause of plane crashes. 4 The specially created fissures at
the edge of the bird’s wing transmit part of the air. This is a feature that
engineers seek to imitate in modern planes by designing additional small
wing edges on the wings.
Moreover, birds are able to change the shape of their wings in such a
way as to facilitate air flow during takeoff, flight control and landing. They
can also fold their feathers to alter their air resistance, by the use of an
exceedingly complex tendon system. 5
Bird feathers, the underlying skin and subcutaneous muscles, the ten-
dons that connect the bones and organs, the brain, and sense organs are
interdependent. This system, essential for flight, is irreducibly complex. The
absence of any one component will prevent flight. The fact that details such
as the angle and thickness of the feathers’ parts exhibit so little variation is