Flying Creatures: Created or Evolved?
- Tuesday, January 25, 2011
(Condensed and updated from his book By Design,* Chapter 4)
Humans achieved true powered and sustained flight only about one hundred years ago, after many laughable failures. Two Christian bicycle-making brothers, Wilbur and Orville Wright from Dayton, Ohio, carried out the first real flight at Kill Devil Hills near Kitty Hawk in North Carolina at 10:35 a.m. on 17 December 1903.1 Yet airplanes were not the first heavier-than-air fliers. Inventors learned much from hours of bird watching through binoculars. One vital secret they learned was that birds controlled their flight in three axes, which involves control of their wing shape. Thus, the Wright brothers developed a system to control the wing shape on their flying machines.
James DeLaurier, a professor emeritus at the University of Toronto who spent decades studying flapping wings, said: "It's respectable to look at nature for inspiration. We don't come close to doing all the things that nature does."
"It's absolutely good design if you copy nature," concurred Terry Weisshaar, an aeronautics professor at Purdue University. John McMasters, an aerodynamics expert at jet manufacturer Boeing, has taught aircraft design for forty years, and agreed: "One of the rules is never invent anything you don't have to. If you can find a precedent that solves a problem, use that." He added that lessons learned from nature will play an increasing role in new aircraft.2 As an example, "In the future, the swift's flight control might inspire a new generation of engineers to develop morphing microrobotic vehicles that can fly with the agility, efficiency, and short take-off and landing capabilities of insects and birds."3,4
Even before powered flight, pioneers in gliding learned from birds: "The gliding flight of storks inspired the first airplane designs of Otto Lilienthal in the late nineteenth century. The benevolent flight characteristics of these slow and stately gliders invested airplane pioneers with the confidence to take to the skies."4
If it took intelligence and planning to design an airplane, what does it say about the flying machines that the Wright brothers studied? And these can do something that airplanes can't—they can make copies of themselves!
How Do Birds Fly?
Since heavier-than-air machines must overcome gravity, they need some balancing upward force, which comes as a direct result of the special shape of their wings. Birds, and now airplanes, have wings shaped as aerofoils, so that as they move forward, air is deflected downward. This is because the wing is angled slightly upward ("angle of attack") and also because the air follows the curve on the upper surface (because of the "Coanda effect"), which points down. This downward airflow produces an upward force (lift) because of Newton's Third Law of motion,5 which was discovered by another creationist:6 every action has an equal and opposite reaction. You can feel this strong downdraught of air under a helicopter's rotor, which is essentially a rotating wing.
Airplanes need a motor to move forward, while in birds, this effect is produced by flapping. Birds' primary flight feathers are angled in such a way that they force air backward, so the bird is propelled forward, again in compliance with Newton's Third Law.
Special Features of Birds
When birds flap their wings, most of the resulting power is generated by the downstroke. But after the downstroke, something must raise the wing again for the next downstroke. Fortunately, birds have an intricate pulley system—the supracoracoideus muscle pulls on its tendon, which winds around a pulley comprising the coracoid and clavicle bones, then inserts into the humerus or upper arm/wing bone.
Birds can still fly if the tendon is cut, but takeoff is badly hindered when this situation occurs.7 So why would natural selection choose a half-formed pulley? Indeed, there is no evidence of transitional half-pulley systems in the fossil record, and would such a half-pulley be any use at all?8
Alan Feduccia, a world authority on birds at the University of North Carolina at Chapel Hill and an evolutionist himself, says "feathers are a near-perfect adaptation for flight" because they are lightweight, strong, aerodynamically shaped, and have an intricate structure of barbs and hooks. This structure makes them waterproof, and a quick preen with the bill will cause flattened feathers to snap into fully aerodynamic shape again.9
Some evolutionists claim that feathers evolved from scales, but scales are folds in skin. Feathers, on the other hand, are complex structures with barbs, barbules, and hooks. Feathers also originate in a totally different way, from follicles inside the skin in a manner akin to hair. Finally, feather proteins (φ-keratins) are biochemically different from skin and scale proteins (α-keratins) as well.
Special flow-through lung
Bird lungs are very different from reptile lungs. A reptile lung is like a bellows, that is, air is breathed in, and blood takes up the oxygen and releases carbon dioxide. The stale air is then breathed out the same way it came in.
However, birds have a complicated system of air sacs that makes use of even the hollow bones. This system keeps air flowing in one direction through special tubes (parabronchi,singular parabronchus) in the lung, and blood moves through the lung's blood vessels in the opposite direction for efficient oxygen uptake,10 an excellent engineering design.11
How would the "bellows" style of lungs of reptiles evolve gradually into avian lungs? The hypothetical intermediate stages could not conceivably function properly, meaning the poor animal would be unable to breathe. One of the first developmental stages would be a poor creature with a diaphragmatic hernia (hole in the diaphragm), and natural selection would work against this. Lung experts who studied the incredibly well preserved fossil of Sinosauropteryx (an alleged evolutionary ancestor of birds) argued that "its bellows-like lungs could not have evolved into high performance lungs of modern birds."12
Could Bird Flight Have Evolved?
There are two main theories for the origin of flying birds: (1) that birds evolved "ground up" from running dinosaurs (the cursorial theory) and (2) that they evolved "trees-down" from small reptiles (the arboreal theory). Both sides produce devastating arguments against the other side. The evidence indicates that the critics are both right—birds did not evolve either from running dinos or from tree-living mini-crocodiles. Yet, whenever one or the other theory is proposed, the popular press fosters the impression that this new "evidence" mounts a cumulative case for bird evolution, when in reality this new evidence cancels out at least one of the theories.
Furthermore, many of the arguments don't understand what flight involves. For example, the skeptic-dominated Australian Museum asserted that certain dinosaurs evolved a certain bone that "also allowed them to move their hands in a broad fan-shaped motion and to snap their long arms and grasping fingers forward to grab fleeing prey. This powerful, flapping motion has today become an important part of the flight stroke in modern birds."13
However, this would be just the wrong sort of motion for flight. A flap in the forward direction would have the effect of pushing the bird backward. Also, feathers are not the sorts of structures that would be useful on limbs that flap at a prey animal, since the prey would be damaged by their pounding.
Finally, the purpose of the wings is to force air backward and downward so that the bird is propelled forward and kept aloft. Therefore, wings must form a wide surface that has high air resistance, so that they can move large volumes of air. But for a limb designed to grab forward at prey, it's an advantage to have a surface that has low air resistance, i.e. lets air through easily. Picture, for example, the holes in a fly swatter or streamlined shapes designed to move through the air as opposed to moving the air itself. Also, the rush of air from the proto-wing would warn the prey of its impending doom!
Not the Only Fliers
Birds are just one type of flying animal. Three other groups of animals also include flying creatures, and each of those groups—bats, pterosaurs, and insects—has unique features.
Bats are the mammalian flyers, and they display many unique features that make them very maneuverable. Their wings are formed by skin that is stretched out over highly elongated fingers. This wing surface is very stretchy and flexible, and consequently bats can generate unusual wing shapes and motions. A thorough understanding of the bat's wing structure could help engineers design small flying vehicles, such as those being developed for military reconnaissance.14
The fossil record sheds no light on the bat's alleged evolution from non-flying creatures. The oldest known (by evolutionary "dating" methods) fossil bats are practically indistinguishable from modern ones (see picture, right). Evolutionist Paul Sereno admitted: "For use in understanding the evolution of vertebrate flight, the early record of pterosaurs and bats is disappointing: Their most primitive representatives are fully transformed as capable fliers."15
Pterodactyls (meaning "winged finger"), as the name implies, have a wing made of skin attached to an extremely long fourth finger. Scientists have long wondered how they could have flown. They seemed to be too ungainly to be able to rise into the air from the ground or to land safely without breaking their delicate wings. Quite reasonably, some scientists proposed that there must have been greater air pressure in the past.
But these assumptions had overlooked a tiny bone called the "pteroid." Scientists at Cambridge University, UK, studied pterosaur fossils and observed that the pteroid pointed forward.16 This pteroid evidently supported a front flap of skin that acted as a movable leading edge on the wing.
The pteroid and flap enabled the pterosaur to use "aerodynamic tricks like those found in modern aircraft."17 Angling this flap would increase lift by a huge 30%, so even the largest pterosaurs could take off by simply spreading their wings into a moderate breeze. And this extra lift would mean their minimum flying speed (i.e., below which they would stall) was reduced by 15%, allowing a smooth landing. Also, by flexing the pteroid on one wing and extending it on the other, they would have achieved different lifts on both wings, enabling them to bank, just like an airplane does.
Insects—How Can They Fly at All?
It has often been said that, according to the laws of aerodynamics, insects shouldn't be able to fly. But of course they do—brilliantly. Research over the past decade or so is revealing how insects do manage to fly in ways that put the achievements and maneuverability of our most advanced aircraft to shame.
Insect wings have a very complex motion, rotating and changing the camber (slope). This generates swirling "eddies" from the edges of insect wings, and these boost lift.18,19 It required sophisticated programming from intelligent design to make an experimental "robot insect" flap properly. Thus, it is reasonable to presume that the real insects likewise were programmed by intelligent design.
The animal kingdom uses four main ways to "solve the problem" of heavier-than-air flying machines. All exploit the principles of aerodynamics in ingenious ways that aircraft designers are still learning. The new discoveries of the ingenuity of flying creatures, as well as the continued lack of discoveries of transitional forms, present a huge obstacle to the theories of evolution.
Dr. Sarfati's Ph.D. in physical chemistry is from Victoria University, Wellington, New Zealand. He is the author of some of the world's most well-known creation books, including By Design, Refuting Evolution(1 & 2), Refuting Compromise, and his latest, The Greatest Hoax on Earth? Refuting Dawkins on Evolution. A former chess champion of New Zealand, he works for Creation Ministries International (in Australia from 1996-2010, thereafter in Atlanta, Georgia).
*A review of this book may be found at this website address: http://thehomeschoolmagazine.com/Homeschool_Reviews/3524.php.
1. Lamont, A., "The Wright Brothers—pioneers in the skies,"Creation 13(4):24-27, 1991; creation.com/wright.
2. Levin, A., "Flying creatures may help create aviation of future," http://www.usatoday.com/tech/science/discoveries/2007-02-13-aviation-birds_x.htm, USA Today, 13 February 2007.
3. Videler, J.J., E. J. Stamhuis, and G.D.E. Povel, "Leading-edge vortex lifts swifts," Nature 306(5703):1960-1962, 10 December 2004.
4. Müller, U. K. and D. Lentink, "Turning on a dime," Science 306(5703):1899-1900, 10 December 2004.
5. Many explanations of bird and aeroplane flight involve the Bernoulli Principle: faster airflow on top causing a pressure drop. Supposedly, the greater pressure on the bottom surface produces lift. But calculations show that this is far too slight to explain lift. Also, the Third Law explanation, unlike the Bernoulli Principle, explains why planes can fly upside down with a high enough angle of attack. See Anderson, D.F. and S. Eberhardt, Understanding Flight, McGraw-Hill, 2001.
6. Lamont, A., "Sir Isaac Newton (1642/3-1727): A Scientific Genius,"Creation 12(3):48-51, 1990, creation.com/newton.
7. Fastovsky, D. amd D. Weishampel, The Evolution and Extinction of Dinosaurs, p. 298, Cambridge University Press, 1996.
8. Sodera,V., One Small Speck to Man: The Evolution Myth, pp. 292-302, Vija Sodera Publications, Bognor Regis, UK, 2003.
9. Feduccia, A., The Origin and Evolution of Birds, p. 130, Yale University Press, 1996.
10. Denton, M., Evolution, a Theory in Crisis, pp. 199-213, Adler & Adler, Bethesda, MD, 198; K. Schmidt-Nielsen, "How Birds Breathe," Scientific American, December 1971, pp. 72-79.
11. Engineers make much use of this principle of counter-current exchange, which is common in living organisms as well—see P. F. Scholander, "The Wonderful Net," Scientific American, April 1957, pp. 96-107.
12. Gibbons, A., "New Feathered Fossil Brings Dinosaurs and Birds Closer," Science 274:720-721, 1996.
13. Sarfati, J., "Skeptics/Australian Museum ‘Feathered Dinosaur' display:
Knockdown argument against creation?" creation.com/dinodisplay, 26 November 2002.
14. Pearson, A., "Bats in flight may provide military inspiration," NewScientist.com news service, newscientist.com, 27 February 2007.
15. Sereno, Paul C., "The evolution of dinosaurs," Science284(5423):2137-2147 (quote on p. 2143), June 25, 1999.
16. Wilkinson, M. T., D. M. Unwin, C. P. Ellington, "High lift function of the pteroid bone and forewing of pterosaurs," Proceedings of the Royal Society 273(1582):119-126, 7 January 2006 (DOI: 10.1098/rspb.2005.3278)
17. Lorenzi, R., "Pterosaurs flew like jumbo jets," News in Science, http://www.abc.net.au/science/news/stories/s1483770.htm, 17 October 2005.
18. After "Insects—defying the laws of aerodynamics?" Creation 20(2):31, March 1998; creation.com/insects.
19. "On a wing and a vortex," New Scientist 156(2103):24-27, 11 October 1997.
Copyright 2010. Originally appeared in The Old Schoolhouse® Magazine, Fall 2010. Used with permission. Visit them at http://www.TheHomeschoolMagazine.com.
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