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Zaynab |
Birds: Structure and Flight courtesy of IFSA |
Zaynab |
“Do
they not see the birds committed to fly in the atmosphere of the sky? None holds
them up in
the air except Allah. This should be (sufficient) proof for people who believe”.
(Quran16:79)
That birds can fly and so efficiently is miraculous. In order to work, such a
flying machine must be amazingly lightweight and yet incredibly tough and strong. To take off and
maintain flight, the bird can’t be too heavy. Yet to survive the conditions faced in the air and the
force of landing, it must be tough so as not to break
on impact. These two qualities (lightness and toughness) are exactly how a bird is constructed.
The
Skeletal Framework
The skeletal framework of a bird is rigidly interconnected with a very sturdy
spinal column of fused vertebrae. The neck is strong but incredibly flexible as it must have the
strength to support the head (keeping it motion-less when in flight) yet flexible and ready to swing it
suddenly in any direction, bending far downward or up-ward to spot prey or predators. The number of
vertebrae in a bird’s neck varies from long-necked to short-necked birds.
This may sound obvious. But a mouse has the same number of cervical vertebrae as
a giraffe (seven). Birds have a minimum of 11. Flexibility of the neck is achieved by a system of
long bands of muscles and smaller muscles that are perfectly co-ordinated. From the slow turning of an
owl’s head to the flash of a heron catching a fish, it’s a masterful machine.
Bones in the bird are hollow and thin-walled for lightness with internal struts
for support. All weight is concentrated toward the
centre of the bird. At that centre is a very large breastbone to which are
attached the pectoral muscles, the mighty muscles which drive the wings. Flight muscles
may account for 25-30 percent of a bird’s weight, compared to pectoral muscles in the human which
weigh less than one percent of total weight. These muscles working to drive the wings build up great heat.
To
counteract this, the bird has the most efficient respiratory system of any
vertebrate. Rather than a single pair of lungs the bird
has a system of air sacs throughout the body even in some of the hollow spaces
in the bones. The air is taken in quickly to all important parts of the body and the bird’s faster
heartbeat provides rapid circulation.
Eyesight
Good eyesight is an important prerequisite of flight. A bird relies more heavily
on vision than most animals. In some birds their eyes actually weigh more than their brains. Birds can see
distant things as much as eight times more clearly than man can, and they also see close up much better.
Most birds have both monocular and binocular vision. They can rely on what one eye sees close up and
then count on sharper binocular vision for distances.
"Have they not seen the birds above them lined up in columns and spreading their
wings? The Most Gracious is the
One who holds them in the air. He is Seer of all things." (Quran 67:19)
Wings and Feathers
Most important to flight are the wings and feathers. The wing is really an arm
with a large ball joint fitting into the socket in the shoulder. This is a specialized joint allowing great
mobility. The way the bird can rotate as well as flap up and down gives the bird the ability to manoeuvre, slow
down, change direction suddenly and land gracefully.
The
feather is a unique and wonderful creation. It’s light yet sturdy, flexible,
versatile and easy to care for, provides cushioning, thermal insulation, and is water repellent and replaceable.
Bright
coloured feathers are important in some bird species for attracting a mate and for territorial
displays. Some birds have feathers
camouflaged like their surroundings to help them hide.
The
simple looking feather is actually a very complex mechanism. There is a centre
shaft attached to the skin. From this project many parallel branches or barbs which in turn bear
smaller barbules, which
With all the bird does, there is continuous wear and tear on the feathers, so
they must be replaceable. That’s why birds malt on a regular basis. Malting is a precise process,
triggered in the least severe season. The feathers are discarded usually in pairs (one from the right side and the
corresponding one from the left). And never so many that the bird can’t fly, although it may be weakened. To
compensate, new feathers grow in very fast.
None holds the birds in the air except Allah.
Allah
holds them in the air. Allah gives them the physical construction to fly, the
use of wings. They can raise and lower the wings, can move them for-ward or back, they can reduce the
wing area, can
Hummingbirds can fly backwards. Penguins, who don’t fly, use their wings like
a powerful oar to move quickly through the water. Hawks can turn upside down in full flight to catch
smaller birds trying to escape, then right themselves and fly on without missing a beat.
The Wind
Birds
use the wind with great skill, as if they studied science. Some birds use
land drafts to soar and glide, like an eagle using
the currents in a canyon. Over water, seabirds are incredibly adept at using
The
structure of the bird and the miracle of flight are signs from Allah if we
choose to see them. This is a proof for people who believe.
Lydia Kelley.
Provided with kind permission from; IFSA Mailing list, Islamic Forum for Science
and the Arts.
http://www.members.ozemail.com.au/~zaynabelfatah
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Last updated on 31/10/2002 |
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