Yet another flap about dino-to-bird evolution
Published: 4 February 2006 (GMT+10)
What’s the latest news?
Once more, a theory about the origin of bird flight is in the news. The latest theory is that a bird’s flight apparatus first evolved to aid traction as their ancestors ran up slopes. Dr Kenneth P. Dial of the Flight Laboratory, University of Montana, Missoula, published his paper in Science.1 Dial observed the behaviour of chukar partridge chicks as they ran, and worked out why they flapped their wings. He found that the birds employed ‘wing-assisted incline running’ (WAIR).
Here, the flapping did not lift the birds, but rather, the opposite—they pressed them into the ground for better traction, working like spoilers on race cars. Dial performed experiments on a number of chicks. He trimmed the flight feathers (remiges) to various lengths, and made them run up slopes of different slopes and textures.
He found that even hatchlings can get up inclines of up to 45°, without flapping. But if they flapped, they could scale greater slopes: hatchlings could climb a 50° incline, four-day old chicks could climb a 60-degree slope, 20-day-old chicks could climb a 95° almost vertical surface, and adults can run up a 105° overhang.
Dial also compared birds at the same day of development, seven days after hatching, but with different lengths of flight feather removed. The hatchlings with remiges removed could not scale an incline above 60°, even on a surface covered in sandpaper to aid traction. Those withhalf-trimmed remiges could climb greater slopes, but still 10° to 20° below that of the control birds with full remiges.
All three groups were tested on smooth surfaces. None could climb slopes greater than 50°, because of slippage, and the presence or absence of remiges made no difference. This is consistent with traction being an important factor.
For more rigorous demonstration of the forces involved, Dial also used two accelerometers to measure the acceleration in the forward and vertical directions. He found that during a large part of the flapping cycle, the bird was forced against the surface regardless of its angle, which would increase traction.
So far, this is careful scientific work, testing a hypothesis and ruling out alternatives, and it provides new insight into running chicks. But that’s where the science ends. When this is applied to evolution, speculation takes over, and leads to conclusions that are not warranted by the evidence.
Once again, for these evolutionists, the presumptuous question is not of ‘DID dinosaurs evolve into birds?’, but ‘HOW did this “proven” transition occur?’ We have also noted that even some leading evolutionary paleo-ornithologists such as Dr Storrs Olson of the Smithsonian called the dino-to-bird dogma one of the great ‘scientific hoaxes of our age’ which is ‘actively promulgated by a cadre of zealous scientists’. As we have shown, we could add the Skeptics’ Australian Museum Display to Olson’s list of things promoted by such means.
An organization which seems to fit Olson’s criteria would be the pretentiously named Humanist-founded-and-operated National Center for Science Education, which describes itself as ‘the only organization entirely devoted to defending the teaching of evolution in the public schools.’ Its President, Dr Kevin Padian, and his colleague Dr Alan Gishlick, are outspoken dino-to-bird advocates. They were among the most excited about Dial’s theory.2
Padian said that the alleged dinosaur ancestors of birds ‘could have used a forward predatory grab similar to a flight stroke.’2 This could explain where the Australian Museum got its misinformation. But as I pointed out here, this would have the opposite effect from what’s needed for flight, which also applies to Dial’s theory, as will be shown.
Gishlick said that a good candidate for Dial’s mechanism was Microraptor, which he claimed was ‘a feathered dinosaur the size of a pigeon that was chased enough to make it want to run up into the sky.’2 What he failed to mention is that the type specimen was actually half of the notorious fraud Archaeoraptor.3 This partial skeleton has digits that point to its being scansorial rather than cursorial, i.e. a climber rather than a runner.3
(A few days later, the name Microraptor gui was applied to an alleged four-winged feathered dinosaur that lived supposedly 124–128 Ma (million years) ago.4 Yet another supposed ‘ancestor’ for birds that lived ~25 Ma after the first undoubted bird Archaeopteryx (153 Ma) and even about 10 Ma after the beaked bird Confuciusornis (135 Ma)! We soon published more information in the article New four-winged feathered dinosaur?.)
What are the problems?
Once again, for these people, the presumptuous question is not of ‘DID dinosaurs evolve into birds?’, but ‘HOW did this “proven” transition occur?’ We have already noted major problems with this, and Dr Dial’s experimental findings cannot overcome these in the least. For example, two huge problems are the different development of digits in the embryo and the major differences in the lung structure.
Here, Dial uses undoubted birds to postulate a theory about their origin. It makes sense that birds, which already have the musculature and great control over flying wings, should also have programmed instincts to use them to aid traction. But it makes no sense that natural selection for traction should lead to flight. Rather, on the face of it, traction would require the opposite force to lift, so the selective direction would be away from flight. So Dial proposes that somehow the motions that lead to traction must be redirected to produce the movement required for flight.
However, if running up slopes were a major selective factor, then one would expect increased musculature in the hindquarters to drive the legs. Then greater slopes could be scaled simply by momentum. Also, the extra weight of the muscles would increase traction automatically. These effects are probably the main reason the older birds are better slope climbers. However, increasing the weight on the hindquarters of a dinosaur is precisely the wrong way to turn it into a bird. In fact, the heaviness of dinosaur hindquarters is a major argument, even by evolutionists, against the theropod ancestry of birds.5
All this analysis shows how much evolutionary theorizing is ‘just-so’ story-telling. However, this is tolerated because they ‘have a prior commitment, a commitment to materialism’, as Lewontin admits candidly. Dial’s story would entail small running dinosaurs in a wonderful environment, with a handy gradation of inclined planes. Here, natural selection would supposedly gradually craft an improvement in wing-assisted traction—while mysteriously ignoring the greater effects of weight-assisted traction and muscle-assisted speed!
Once more, the dogma takes precedence over the data. And here we see yet another illustration of the fact that creationists don’t dispute any observations made by evolutionists, just their interpretations.
- Dial, K.P., Wing-Assisted incline running and the evolution of flight, Science 299(5605):402–404, 17 January 2003. Return to text.
- Gorman, J., Chicks offer insight into origin of flight, New York Times, 17 January 2003. Return to text.
- Microraptor, Dinosauricon, accessed 23 January 2003. Return to text.
- Four-winged dinosaur ‘fills evolutionary gap’, ABC [Australia] Online, 23 January 2003. Return to text.
- Feduccia, A.; cited in Ann Gibbons, A., New Feathered Fossil Brings Dinosaurs and Birds Closer, Science 274:720–721, 1996. Return to text.