Ancient Birds Flew On All Fours

The earliest known ancestor of modern-day birds took to the skies by gliding from trees using primitive feathered wings on their arms and legs, according to new research by a University of Calgary paleontologist. In a paper published in the journal Paleobiology, Department of Biological Sciences PhD student Nick Longrich challenges the idea that birds began flying by taking off from the ground while running and shows that the dinosaur-like bird Archaeopteryx soared using wing-like feathers on all of its limbs.

"The discussions about the origins of avian flight have been dominated by the so-called 'ground up' and 'trees down' hypotheses," Longrich said. "This paper puts forward some of the strongest evidence yet that birds descended from arboreal parachuters and gliders, similar to modern flying squirrels."

The first fossil of the Jurassic-era dinosaur Archaeopteryx lithographica was discovered in Germany in 1861, two years after Charles Darwin published his theory of evolution in On The Origin of Species. Since then, eight additional specimens have been unearthed and Archaeopteryx is considered the best evidence that birds evolved from dinosaurs since it had both feathers and a bird-like wishbone, along with classic reptilian features of a long bony tail, claws and teeth.

Although scientists immediately noticed feather-like structures on the hind limbs, they were dismissed as insulating body feathers that didn't play a role in the animal's flight. It wasn't until several four-winged dinosaurs in China were described in 2002 that researchers began to re-examine Archaeopteryx's legs.

"The idea of a multi-winged Archaeopteryx has been around for more than a century, but it hasn't received much attention," Longrich said. "I believe one reason for this is that people tend to see what they want or expect to see. Everybody knows that birds don't have four wings, so we overlooked them even when they were right under our noses."

Under the supervision of professor Anthony Russell, Longrich examined Archaeopteryx fossils and determined that the dinosaur's leg feathers have an aerodynamic structure that imply its rear limbs likely acted as lift-generating "winglets" that played a significant role in flight.

"ah no, as usual you are wrong...a transitional fossil would be one that shows a partial leg, a half wing, a half feathered wing and half scaled wing...but all the examples you give are fully functioning features.

That is so wrong I don't know whether to laugh or cry.

The SToE does not predict nor require that there be a half a wing (although flying squirrels and flying lemurs could be considered to sport half wings), or a wing that is half feathered half scaled. (By the way, what do you call those funny unfeather like things on a birds legs?)

We have fossils of fully feathered dinosaurs (other than their feet). They have no wings. That pretty much removes the half feathered half scale wing argument. The non-winged, non-flying dinosaurs also had pneumatic bones, their bones had air sacs in them just like modern birds.

To form a wing from an arm and a hand, all that is necessary is to lengthen the fingers, fuse the wrist, stretch the skin to the ends of those fingers from the body and strengthen the muscle and its connection points.

We have extant mammals that show part of this in action. Flying squirrels have a membrane that stretches from the wrists of their fore limbs to the wrists of their hind limbs. Flying lemurs have even more membrane that stretches from their hind limbs to their tail. This makes it obvious that organisms can do quite well with nothing but a stretched membrane.

Now to elongate the bone structure under the non-half wing feathered membrane. If we examine the bone structure of a bat we see that the bat has fingers similar to other mammals but much longer. It is limited to a featherless membrane with which it flies very well.

The length of bones can easily be modified by 'micro-evolution'. We have evidence of this with our work selecting dogs with different length legs. Length can be changed without resorting to a saltational concept of macro-evolution.

So let's see what we have. We have a small reptile covered in feathers. Any 'half' features there? Nope.

Next we have a descendant of that feathered reptile who has developed a 'feathered' membrane from its finger tips to its body. Can it fly? Nope. Can it jump from tree stump to tree stump? Yup. Better than it neighbours? Likely. Any 'half' wings or limbs? Nope.

Next comes a critter descended from the previous who has feathered membrane from the tips of his front limbs stretching to the tips of his hind legs. He's become a master glider. He can jump farther than his neighbours. He can also surprise his food better than his neighbours so he eats better than they do. To support his weight while gliding the muscles supporting his limbs are larger and the connection points are strengthened. Any half wings or half limbs here? Nope.

The next descendant retains the feathered membrane from his ancestor but has a number of the fingers of his front limbs lengthen. The gliding war has just become more intense. With more surface area to provide lift he can out glide and out hunt those of his relative species without the longer fingers. Any half wings here? Nope.

The next incarnation of this line actually has the lifting surface area reduced. Instead of having the membrane stretch between the front and rear limbs, the front membrane now stretches from the much longer fingers to his mid body and the rear limbs have lost the leading membrane but retained the trailing membrane. What advantage does this give him? He can out maneuver his relative species. His muscles and their connection points continue to strengthen. Any half wings here? Nope.

I'm sure you can see where I am going with this. The point is, wings are nothing but a modification of what the original organism already had. There is no need and definitely no expectation of a half limb anywhere in the evolution. If you've been told that half wings are necessary you've been lied to.

BTW, we have many fossils that describe much of what I have put forward.

This isn't to say that there are not some features we would consider to be reduced in function *given a specific environment*. A penguin's wings are really poor for flying in air, but they are great for flying under water. A Pinniped's flippers are really bad for walking on land but great for swimming. Then we have birds such as the auk family (Alcidae) which both dive and fly but their abilities are reduced from other birds. They dive well but not as well as pure diving birds such as penguins and they fly but not as well as birds such as seagulls which also spend time around water.

"all you are describing the all the variants of good design by God...

I'm describing what the StoE (Evolution) predicts, requires and has been found. What you believe is a strawman, designed by and for creationists. It has no resemblance to the evolution Darwin put forward nor the version of evolution modern scientists have developed.

"thanx for making my argument for me.....

Look again.

"(like shooting fish in a barrel)

Your arrogance is unfounded.

For those that don't know and the lurkers: The measure of evolution is not whether certain features gain or lose function but how much the change, any change, affects future ability to pass on genes.

Yes, I *knew* that.

I just didn't see an obvious change to the environment that would first favor four wings, then two.

Recall, as some other poster on this thread pointed out, that there are all kinds of concomitant changes to lungs, bones, genitalia, what have you that all seem to go together in a package in the birds.

If the same genes cover very different organs and structures, no problem.

If they don't, the process becomes more messy, or more problematic.

Full Disclosure: Yes, I already thought of the "ontogeny recapitulates philogeny" in this regard, especially with respect to formation of fingers / toes on hands and feet (webbing more or less, followed by massive cell death to "carve out" the digits).

Cheers!

" I just didn't see an obvious change to the environment that would first favor four wings, then two.

That depends on whether you consider the species undergoing the change part of its own environment. All it takes is change in the morphology of one of the members of a population to change the direction of selection. You also have to remember that there will be no time in the lifetime of a species where there are no selection forces in action.

"Recall, as some other poster on this thread pointed out, that there are all kinds of concomitant changes to lungs, bones, genitalia, what have you that all seem to go together in a package in the birds.

That poster has a penchant for creating strawman versions of evolutionary processes. Both feathers and pneumatic bones existed in dinosaurs before they developed flight. As far as developing a stronger bone structure to support larger muscles through reinforcing the rib cage, Archaeopteryx flew without that bridging and the fusing of clavicles into the 'wishbone' started in dinosaurs before flight.

There is no reason to believe that all the features we find in modern birds had to develop simultaneously. Although modern birds rely on all the features they have this is to be expected, evolution has the tendency to reduce or change in function features with marginal use, but flight does not need all of those features as can be seen in the other organisms which can fly, and those features can be attained through incremental modification.

QUOTE MINE ALERT, Level 3

Here is one the quotations you posted above:

"...Every paleontologist knows that most new species, genera, and families, and that nearly all categories above the level of family appear in the record suddenly and are not led up to by known, gradual, completely continuous transitional sequences.” [George Gaylord Simpson (evolutionist), The Major Features of Evolution, New York, Columbia University Press, 1953 p. 360.]

Here is the actual quotation (with the little part you quoted in blue; look how much was left out):

The chances that the remains of an organism will be buried, fossilized, preserved in the rock to our day, then exposed on the surface of dry land and found by a paleontologist before they disintegrate are extremely small, practically infinitesimal. The discovery of a fossil of a particular species, out of the thousands of millions that have inhabited the earth, seems almost like a miracle even to a paleontologist who has spent a good part of his life performing the miracle. Certainly paleontologists have found samples of an extremely small fraction, only, of the earth's extinct species, and even for groups that are most readily preserved and found as fossils they can never expect to find more than a fraction.
In view of these facts, the record already acquired is amazingly good. It provides us with many detailed examples of a great variety of evolutionary phenomena on lower and intermediate levels and with rather abundant data that can be used either by controlled extrapolation or on a statistical sampling basis for inferences as to phenomena on all levels up to the highest. Among the examples are many in which, beyond the slightest doubt, a species or genus has been gradually transformed into another. Such gradual transformation is also fairly well exemplified for subfamilies and occasionally for families, as the groups are commonly ranked. Splitting and subsequent gradual divergence of species is also exemplified, although not as richly as phyletic transformation of species (no doubt because splitting of species usually involves spatial separation and paleontological samples are rarely adequate in spatial distribution). Splitting and gradual divergence of genera is exemplified very well and in a large variety of organisms. Complete examples for subfamilies and families are also known, but are less common.

In spite of these examples, it remains true, as every paleontologist knows, that most new species, genera, and families and that nearly all new categories above the level of families appear in the record suddenly and are not led up to by known, gradual, completely continuous transitional sequences. When paleontological collecting was still in its infancy and no clear examples of transitional origin had been found, most paleontologists were anti-evolutionists. Darwin (1859) recognized the fact that paleontology then seemed to provide evidence against rather than for evolution in general or the gradual origin of taxonomic characters in particular. Now we do have many examples of transitional sequences. Almost all paleontologists recognize that the discovery of a complete transition is in any case unlikely. Most of them find it logical, if not scientifically required, to assume that the sudden appearance of a new systematic group is not evidence for special creation or for saltation, but simply means that a full transitional sequence more or less like those that are known did occur and simply has not been found in this instance.

This information, and information on some of your other mined quotes can be found at The Quote Mine Project: Or, Lies, Damned Lies and Quote Mines.

Changes the context of your quote, doesn't it? Now don't you feel silly?

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