Freethought & Rationalism Archive

Principia · 01-16-2003, 05:44 PM

An interesting article positing a new use of wings in proto-birds, which suggests their evolutionary advantage:

Quote:

The behavior of chukhar partridge chicks, which can run straight up the side of a hay bale or a tree while flapping their wings, may offer a new window on the origin of flight in birds.

Feathered dinosaurs may have done something similar, Dr. Kenneth P. Dial of the University of Montana suggests in today's issue of Science. He suggests that they too flapped their wings to help them climb, which brought them off the ground and closer to discovering the aerial possibilities of their wings. Even incompletely feathered proto-wings, Dr. Dial says, would have been useful in running up steep inclines.

One of Dr. Dial's findings, which has surprised other scientists who study the evolution of flight, is that the chicks he studied did not use their wings to raise them up, off the ground. The wing beats served the same purpose as spoilers on race cars. The force generated by flapping pressed the chicks into the surface on which they were running for better traction. As Dr. Dial said of his finding, "It's not intuitive."

He came upon the behavior by accident. His teenage son, Terry, was helping him study the development of flight in chukhar chicks. While Dr. Dial was away on a trip, his son was keeping track of the young birds as their feathers grew and they gradually launched themselves on longer flights, both horizontally and vertically.

The vertical flights used hay bales as an obstacle. When Dr. Dial returned from a trip, he said, his son told him the chicks were not staying with the program. "They're cheating," Dr. Dial recalled his son telling him, "They're not flying anymore. They're running up."

Dr. Dial had to see for himself, then he had to videotape the behavior, and then he had to do a series of experiments varying the incline and the surface the birds were running up, and clipping the feathers at different lengths.

He found that the chicks were using a flight stroke, but changing the angle to press their feet against the running surface. More feathers meant more effective use of the wings, but partly feathered wings provided a significant benefit.

Dr. Dial concluded that proto-birds with somewhat similar wings may have done the same thing, and that the climbing ability they gained would have given them an evolutionary edge, even if the wings were not yet useful for full flight.

Once the proto-birds were up a bush, or wall or tree, they would be in a position to discover what wings could do in the air. This evolutionary path to flight, he says, is different than previous models in which proto-birds first launched either from the trees or the ground, called the arboreal and cursorial models. "It's both and neither," Dr. Dial said. [...]

For those of you with access to Science, here is the corresponding link: http://www.sciencemag.org/cgi/content/full/299/5605/402 The author (Kenneth Dial) offered the following hypothesis concerning wing-assisted incline running (WAIR):

Quote:

[...] I propose that the incipiently feathered forelimbs of small, bipedal proto-birds provided the same locomotor advantages for inclined running as are present in extant birds. Whether sprinting across an obstacle-filled terrain or up inclined or even vertical surfaces, being chased, or chasing, an animal capable of employing WAIR enjoys improved hindlimb traction (Fig. 2). In a proto-bird, this behavior would have represented the intermediate stage in the development of flight-capable, aerodynamic wings. The WAIR hypothesis resolves many of the limitations associated with the popular arboreal and cursorial scenerios.

The propulsive excursion of the forelimbs of most tetrapods, in which the forelimbs protract and retract in anteroposterior planes, differs fundamentally from that in flying forms (i.e., birds, bats, and pterosaurs), which primarily involves elevation and depression in a transverse, dorsoventral plane (20). Forelimb excursion during terrestrial flap-running in gallinaceous birds negotiating intermediate slopes (~45� to 60�) has a strong anteroposterior component, in contrast to a transverse stroke during flight (Fig. 2, D and F). As in the intermediate condition exemplified by the glenoid orientation of Archaeopteryx (20), the anteroposterior limb excursion employed by juvenile and adult ground birds during WAIR exhibits the humeral movement expected of a transitional stage. Although I propose that the net force vectors from proto-wings initially were directed toward the substrate to augment hindlimb traction, redirected movements would have permitted rudimentary aerial ascent and controlled descent from elevated refuges, as is observed in extant juvenile galliforms. The ontogenetic trajectories of WAIR behavior in extant birds offer a plausible scenario for incremental adaptive plateaus that feathered theropods (e.g., Caudipteryx) achieved in developing aerial flight.

Wing-Assisted Incline Running and the Evolution of Flight

Kenneth P. Dial
Science Jan 17 2003: 402-404.

Albion · 01-16-2003, 11:30 PM

It's interesting that this has only just appeared, because it's included as one of the possible precursors of flight in the Dinobirds exhibition at the Natural History Museum in London, which opened last summer. Here's an extract from the website that mentions Dr Dial and his research:

"Studying living animals can throw light on their evolutionary past. Dr Ken Dial of Flight Lab, Montana University, USA, noticed the ability of gamebird chicks to escape danger by scrambling up vertical surfaces. The chicks first run very fast, flapping their immature, partially feathered wings, frantically creating enough momentum to run up a vertical surface to safety. Could this survival instinct be the origin of flight?"

Click here

Oolon Colluphid · 01-17-2003, 03:57 AM

Albion, you beat me to saying that

The exhibition even includes looped video footage of the birds doing this weird running-up-trees thing.

The DinoBird Exhibition is completely brilliant. The 'fuzzy raptor', for instance -- I'm at a loss to describe how much more impressive (and beautiful) it is in the flesh, er, in the rock

, compared to photos. And 'it' is both the slab and the counter-slab... marvellous!

Do get there if you are in the UK at all, anyone, anywhere in the UK. The alternative, I gather, is a trip to China.

DT

MrDarwin · 01-17-2003, 06:22 AM

Quote:

Originally posted by Albion
"Studying living animals can throw light on their evolutionary past. Dr Ken Dial of Flight Lab, Montana University, USA, noticed the ability of gamebird chicks to escape danger by scrambling up vertical surfaces. The chicks first run very fast, flapping their immature, partially feathered wings, frantically creating enough momentum to run up a vertical surface to safety. Could this survival instinct be the origin of flight?"

But what good is half a wing?

Principia · 01-17-2003, 07:00 AM

Doing a quick search for Dial, I found that he's had this hypothesis for at least a couple of years. Here's an abstract in American Zoologist that suggested the WAIR:

Quote:

Dial KP
On the origin and ontogeny of bird flight: developing wings assist vertical running.
AM ZOOL 40 (6): 998-998 DEC 2000

22.3 DIAL, K.P., University of Montana. On the origin and ontogeny of bird flight: developing wings assist vertical running.

Discussions on the origin of avian flight fall into two philosophical camps: arboreal (tree-down) or cursorial (ground-up) hypotheses, both of which are dominated by paleontological evidence that fails to adequately address logical incremental adaptive stages necessary to achieve fully developed flight mechanics. Here, I present a new model based on novel behavioral and morphological data obtained during post-hatching development of precocial gallinaceous birds. This model offers a solution to the impasse of previous scenarios on the origin of avian flight and differs from the traditional cursorial thesis. Daily progress of locomotor performance (e.g., vertical and horizontal accelerations of flight and terrestrial locomotion) and morphometrics of wing development (e.g., wing loading, feather growth) of three species (Chukar Partridge, n=10; Japanese Quail, n=10; and Ring-necked Pheasant, n=2) from hatching to adult stage were obtained using high-speed video (60�250 Hz) and Doppler radar. To escape being handled, even one-day-old chicks exhibited the following locomotor behavior: they jumped vertically, vigorously beat their featherless forelimbs, and surprisingly swung their hind limbs through an arc similar to that used during over-ground running. Throughout development partially formed wings develop significant aerodynamic forces that assist the legs. This enables birds to �run vertically� achieving substantial heights against rough surfaces such as rocks, cliffs, and tree trunks. This �Assisted Vertical Running Hypothesis� appears consistent with evidence from fossil data and provides incremental adaptive plateaus, as revealed by ontogenetic trajectories, necessary to achieve fully developed avian flight mechanics as observed in living species.

I don't know if any other research had been published since then.

Writer@Large · 01-18-2003, 07:03 AM

I ran across this, and thought I'd bring it here for your perusal:

Flap over dino flight origins

And just so you can say you heard it here first:

<cretinist>

"See, evilutionists can't even agree on how birds evolved, this is just a guess. wheres the half-bird half-dinosaur?"

</cretinist>

--W@L

gallo · 01-18-2003, 06:20 PM

University of Montana! My alma mater (for my masters).

And in spite of the scorn that most on this board direct at my field of study, I am a wild life biologist. We actually deal with living things rather than just think about them.

Baloo · 01-18-2003, 08:04 PM

Another well written summary can be found at Scientific American.

Albion · 01-19-2003, 12:49 AM

Quote:

The DinoBird Exhibition is completely brilliant. The 'fuzzy raptor', for instance -- I'm at a loss to describe how much more impressive (and beautiful) it is in the flesh, er, in the rock

, compared to photos. And 'it' is both the slab and the counter-slab... marvellous!

Do get there if you are in the UK at all, anyone, anywhere in the UK. The alternative, I gather, is a trip to China.

I went to see them, we were in England in September and had a couple of days in London. I made a special trip to the NHM to see the dinobirds, as well as some of the other fossils (unfortunately it was just before the Darwin Centre opened, so I didn't get to see that), walked round the V&A a couple of times, and then walked up to Kensington Palace and toured round there. My legs and feet were killing me after that - somehow you don't realise until afterwards that walking round a museum can involve several miles!

Just received the Dinobirds book from amazon.co.uk; it wasn't out when I visited, but it's a lovely souvenier. Did you see Chris Groves at the BBC board dismiss dinobirds as just birds? With those long bony tails so clearly evident in the fossils? Boggles the mind.

Principia · 01-19-2003, 10:38 AM

There are some pretty neat videos of the experiments Dial did: http://biology.umt.edu/flightlab/videos.htm

01-18-2003, 07:03 AM	#6
Writer@Large Veteran Member Join Date: Sep 2000 Posts: 7,198	New Theory on the Evolution of Flight I ran across this, and thought I'd bring it here for your perusal: Flap over dino flight origins And just so you can say you heard it here first: <cretinist> "See, evilutionists can't even agree on how birds evolved, this is just a guess. wheres the half-bird half-dinosaur?" </cretinist> --W@L

01-19-2003, 10:38 AM	#10
Principia Veteran Member Join Date: Mar 2002 Location: anywhere Posts: 1,976	Videos There are some pretty neat videos of the experiments Dial did: http://biology.umt.edu/flightlab/videos.htm

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01-16-2003, 11:30 PM	#2
Albion Veteran Member Join Date: Jul 2002 Location: US east coast. And www.theroyalforums.com Posts: 2,829	It's interesting that this has only just appeared, because it's included as one of the possible precursors of flight in the Dinobirds exhibition at the Natural History Museum in London, which opened last summer. Here's an extract from the website that mentions Dr Dial and his research: "Studying living animals can throw light on their evolutionary past. Dr Ken Dial of Flight Lab, Montana University, USA, noticed the ability of gamebird chicks to escape danger by scrambling up vertical surfaces. The chicks first run very fast, flapping their immature, partially feathered wings, frantically creating enough momentum to run up a vertical surface to safety. Could this survival instinct be the origin of flight?" Click here

01-17-2003, 03:57 AM	#3
Oolon Colluphid Contributor Join Date: Sep 2000 Location: Alibi: ego ipse hinc extermino Posts: 12,591	Albion, you beat me to saying that The exhibition even includes looped video footage of the birds doing this weird running-up-trees thing. The DinoBird Exhibition is completely brilliant. The 'fuzzy raptor', for instance -- I'm at a loss to describe how much more impressive (and beautiful) it is in the flesh, er, in the rock , compared to photos. And 'it' is both the slab and the counter-slab... marvellous! Do get there if you are in the UK at all, anyone, anywhere in the UK. The alternative, I gather, is a trip to China. DT

01-18-2003, 06:20 PM	#7
gallo Regular Member Join Date: Jun 2001 Location: Houston, TX, US Posts: 244	University of Montana! My alma mater (for my masters). And in spite of the scorn that most on this board direct at my field of study, I am a wild life biologist. We actually deal with living things rather than just think about them.

01-18-2003, 08:04 PM	#8
Baloo Regular Member Join Date: Jun 2000 Location: St. Louis, MO Posts: 417	Another well written summary can be found at Scientific American.

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