The Aerodynamic Origin of Bird Flight

[Protoart]

Much has been written to try to explain the evolution of bird flight. The discussion today revolves around two theories, the "ground-up" and the "tree-down." These theories and their variants have serious flaws as pointed out by the opposite camps. There is another way! My new theory is available now at:

 

protobird.blogspot.com

 

I think you will find it cogent and persuasive. I explain why, how and where flight evolved. I do avoid the fossil record because I'm no paleontologist. But, nothing I propose is contrary to archaeopteryx or the recent finds in China. Please give it a read.

[lucaspa]

Much has been written to try to explain the evolution of bird flight. The discussion today revolves around two theories, the "ground-up" and the "tree-down." These theories and their variants have serious flaws as pointed out by the opposite camps. There is another way! My new theory is available now at:

 

protobird.blogspot.com

 

I think you will find it cogent and persuasive. I explain why, how and where flight evolved. I do avoid the fossil record because I'm no paleontologist. But, nothing I propose is contrary to archaeopteryx or the recent finds in China. Please give it a read.

 

Protoart, you need to read the following article:

3. Kenneth P.Dial, Wing-Assisted Incline Running and the Evolution of Flight. Science, 299: 402-405, Jan 17, 2003.

 

You can find Science in your local library. You also need to know that natural selection can operate differently than you think in your article. You have successive slight improvements on a function only. THere is something called "exaptation" or "cooption from another function". This means that a trait evolves for one function and, as it gets really good at that function, it serendipitously exhibits another function. Both insect and bird flight are examples of this.

 

In birds, feathers are modified scales. The first feathered dinos only show a very few feathers and these generally on the head. In this case the scales were modified as mating signals. The feathers were mating displays, not for flight. Later feathered dinos show short feathers (like down) all over their bodies. In this situation, feathers are acting as insulation, not for flight.

 

As feathers get longer, they are better for insulation. The longer feathers on the forelimbs also help the dino do something else: run up inclined surfaces. So imagine a small theropod dinosaur chasing its prey -- a smaller dino, a lizard, or a mammal. The prey runs up a steep hill or more likely a fallen tree. By "flapping" its forelimbs, the feathered theropod can run up the hill faster. And catch dinner.

 

As the feathers become longer, the dino can run up steeper and steeper surfaces. As Dial's study shows, "flapping" the forelimbs enables the young bird (that can't fly) to run up slopes that are 100 degrees -- that's more than vertical! So now the theropod dino can chase its prey up the trunk of a tree!

 

However, just at the point where the feathers are long enough to allow running up a vertical surface, the feathers are now long enough to get the animal off the ground if it flaps the forelimbs in a level run! This is not "gradual" flight, it is instant flight.

 

A gradual improvement in running up vertical surfaces ends up with a "sudden" ability to fly!

 

If you want, PM me and I'll send you a PDF copy of the paper. You made a good try, but the problem has been mainly solved. Next time, I suggest you do a search of the primary scientific literature before you post a theory on the web. You might find that somebody has either 1) already come up with your idea or 2) found another answer to the question.

[Protoart]

I've read Dial and have seen the video. It looks like a skateboard stunt. It does not explain the first incremental success that aided survival. Defensive failure does not promote natural selection.

Please read the whole piece. I do mention the first exaptation.

[bombus]

Lucaspa,

 

You present that theory as if it is the accepted one. The 'running raptor' theory is only one possible explanation. This has not been proven - although highly possible, as is the 'tree down' theory.

[CDarwin]

Without the fossil record any hypothesis for the origin of bird flight is hollow speculation.

[Protoart]

But what do you think about my aerodynamic theory?

[iNow]

I think you should read lucaspa's post closely. He is very knowledgable on these topics, and concluded accurately: "the problem has [already] mainly been solved."

[Protoart]

The highest authorities in the field in the evolutionary biology havn't concluded any such thing. Read this...

http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html

or this...

http://wiki.cotch.net/index.php/Learning_to_Fly:_How_Birds_Took_to_the_Air

But what do you think of my aerodynamic theory?

[CDarwin]

But what do you think about my aerodynamic theory?

 

I'm not a biophysicist. If I read it carefully and did some back research then I might be able to offer some feeble opinion, but your basic suggestion seems to be that the first flying birds were water-fowl, which is fine, but without any reference to the fossil record it is an untestable supposition.

 

It is also fairly unnecessary considering the solid fossil-based alternatives that have already been proposed.

 

There also seem to be some definite errors in your logic. Your three "drives" for natural selection are a bit problematic. For which of those reasons did the tetrapod limb evolve, for example? Ultimately all selection is for features that increase reproductive success, either by increasing survivorship or simply increasing the animal's sexiness. That's probably a better way to look at natural selection.

 

You make a bit of a strawman of "ground-up" and "tree-down," too. You paint them as suggesting that the evolution of flight was a directed process, with every incremental step being for flight-related reasons. As Lucaspa pointed out, that is not the case. The fact that hard ground might be more "dangerous" to fall on is absolutely irrelevant. A) That's not necessarily the case, water can be very hard if approached with sufficient speed; B) There's no requirement that evolution happen somewhere "safe." If falling to the ground is fatal, then that's just a stronger selective agent; and C) The whole question is moot if birds were able to successfully keep airborne from the very inception of their flightedness.

[Protoart]

...your basic suggestion seems to be that the first flying birds were water-fowl, which is fine, but without any reference to the fossil record it is an untestable supposition.

 

>>>Some think the protoavis period ( before archeopterix) might be 75 million years. If the initial area where flight originated is gone, what are we supposed to do?

 

...It is also fairly unnecessary considering the solid fossil-based alternatives that have already been proposed.

 

>>>For what species became birds, not for how flight originated.

 

 

...There also seem to be some definite errors in your logic. Your three "drives" for natural selection are a bit problematic. For which of those reasons did the tetrapod limb evolve, for example? Ultimately all selection is for features that increase reproductive success, either by increasing survivorship or simply increasing the animal's sexiness. That's probably a better way to look at natural selection.

 

>>>Surviving includes feeding, not being eaten and reproduction. Does camouflage make one sexy?

 

...You make a bit of a strawman of "ground-up" and "tree-down," too. You paint them as suggesting that the evolution of flight was a directed process, with every incremental step being for flight-related reasons.

 

>>>Good point. Someone else said "flight for flights sake." I already revised my blog post.

 

...As Lucaspa pointed out, that is not the case. The fact that hard ground might be more "dangerous" to fall on is absolutely irrelevant. A) That's not necessarily the case, water can be very hard if approached with sufficient speed;

 

>>> One doesn't jump cliffs until they have masterd banks.

 

...B) There's no requirement that evolution happen somewhere "safe." If falling to the ground is fatal, then that's just a stronger selective agent; and

 

>>> Harmful failure does not promote natural selection.

 

...C) The whole question is moot if birds were able to successfully keep airborne from the very inception of their flightedness.

 

>>>When pigs fly! Micro evolutionary adaptations over over millions of years is universally accepted.

[lucaspa]

I've read Dial and have seen the video. It looks like a skateboard stunt. It does not explain the first incremental success that aided survival. Defensive failure does not promote natural selection.

Please read the whole piece. I do mention the first exaptation.

 

Please define ""first incremental success that aided survival". You don't mention exaptation at all. You talk about "adaptation". Protoart, you obviously put a lot of time and effort into the work. For that you should be applauded.

 

The running of the birds up inclines is NOT "defensive failure". It's offensive success -- allowing the dino to catch prey that otherwise would have gotten away. I don't think you have read Dial, otherwise you would not have said "defensive failure". Catching prey more often is an "incremental success". Also, you mention speed in your essay. Flapping the forelimbs allows more speed. Exactly what you say is necessary!

 

Let's look at some of what you stated:

"Small wings or fins will be useful only if there is major airspeed to achieve any kind of incremental success."

 

However, by exaptation the "wing" isn't evolving as a wing. It is evolving as something else and then it is fully useful as a wing.

 

"The evolution of the wing can only come if the tail can control its orientation. The tail has to come first."

 

But the tail is already present as a means of balancing a theropod dino as they run on two legs. Theropod dinos had tails a hundred million years before one species got flight. This is where your theory would have benefitted from looking at the paleontology data.

 

"Protobird was a diver! Protobird dove for a fish, swam back to shore and climbed back up to the spot from where it dove, and waited for another fish to come by."

 

That's a lot of energy to spend for food. That climb takes lots of energy for the distance you are looking at. Also, if you have distance, you aren't going to be able to see your prey. And, as you intimated, there isn't that much accuracy. If you are diving for fish, you must be pinpoint accurate. Cormorants are that accurate today, but then they fly around looking for fish! You are proposing a condition that, for thousands of generations, there is something worth diving for adjacent to a cliff. Not very likely.

 

"This new technique would be mimicked by others, maybe the young."

 

Mimicking isn't part of natural selection. That's Lamarckism. For natural selection to work the diver must get more food than those that don't. Therefore have more children to pass the alleles for diving to. More children that have alleles for diving than there are children of non-divers.

 

"Protobird's species were waders."

 

If you wade, you don't have to dive. Look at bears and storks today. They wade, then dart their forelimbs or their necks underwater to grab fish. That's a more efficient way to earn a living by catching fish than climb up a cliff so you can dive. By your theory, diving would be selected against, not for.

 

As I said, you put a lot of thought into this. But when you propose a theory, then you have to be prepared to give it up if the evidence is against it. Don't get too attached to your theory.

 

The highest authorities in the field in the evolutionary biology havn't concluded any such thing. Read this...

http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html

 

Did you read the article beyond its saying there are a number of hypotheses?

 

For instance, the article states "Scientists generally agree that wings must have been exaptations; they were used by the ancestor for one function, and became useful for flight among the descendants (if they weren't exaptations, then they were adaptations, which would mean that they were wings already used for powered flight; a circular argument)."

 

How do wings aid diving? They don't! All divers put their forelimbs against their body in order to enter the water. If they don't, then the force of hitting the water breaks the bones!

 

Now, did you look at the date of the webpages? If they were written before Dial (as was most of the stuff at the Wiki site, since Dial is the latest reference) then you are getting a controversy that existed in the past. For instance, if you only looked at papers more than 3 years ago, you would see a "controversy" over whether birds evolved from dinos or both birds and dinos had a common reptilian ancestor. That controversy has been settled. The Wiki site uses reference prior to Dial to say what the state of the situation was then -- and then there was a controversy.

[Protoart]

"Please define ""first incremental success that aided survival"."

> The first use of an anatomical feature aerodynamically, that natural selection will keep.

 

"You don't mention exaptation at all."

>Yes I do! Didn't you read this: "The tail is the first exaptation. Early rockets had a stick tied to them to keep their flight path more consistent for aiming purposes. The function of the tail will change from a balance control to an attitude control. A headfirst diver will need to control its rotation to keep its aim straight."

 

"The running of the birds up inclines is NOT "defensive failure"."

>In Dial's own words, please read within the first paragraph of each:

http://dbs.umt.edu/flightlab/documents/BundleDialJEB2003.pdf

http://www.aibs.org/bioscience-press-releases/resources/s15-0506.pdf

Look for "reach refugia" in the first and "escape performance" in the second.

 

"Let's look at some of what you stated:

"Small wings or fins will be useful only if there is major airspeed to achieve any kind of incremental success.""

> I think I explain this very well, please re-read"

 

"But the tail is already present as a means of balancing a theropod dino as they run on two legs. Theropod dinos had tails a hundred million years before one species got flight."

>I repeat what you didn't read again. "The tail is the first exaptation. Early rockets had a stick tied to them to keep their flight path more consistent for aiming purposes. The function of the tail will change from a balance control to an attitude control. A headfirst diver will need to control its rotation to keep its aim straight."

 

"Protobird was a diver! Protobird dove for a fish, swam back to shore and climbed back up to the spot from where it dove, and waited for another fish to come by."

"That's a lot of energy to spend for food. That climb takes lots of energy for the distance you are looking at."

>A bank is a short walk from behind.

 

"Cormorants are that accurate today, but then they fly around looking for fish!

>You have confused Terns for Cormorants.

 

"You are proposing a condition that, for thousands of generations, there is something worth diving for adjacent to a cliff. Not very likely."

>Please re-read the part about meandering rivers. Banks are everywhere"

 

"This new technique would be mimicked by others, maybe the young."

 

"Mimicking isn't part of natural selection."

>Then how do aquire an instinct?

 

"That's Lamarckism. For natural selection to work the diver must get more food than those that don't. Therefore have more children to pass the alleles for diving to. More children that have alleles for diving than there are children of non-divers."

>Huh? Traits that work produce more offspring.

 

"If you wade, you don't have to dive. Look at bears and storks today. They wade, then dart their forelimbs or their necks underwater to grab fish. That's a more efficient way to earn a living by catching fish than climb up a cliff so you can dive."

>Extending one's hunting range is instictive. You also didn't read this: "Protobird would expand its wading area by adding the edges and the areas that were normally bypassed where the water was too deep."

 

"As I said, you put a lot of thought into this. But when you propose a theory, then you have to be prepared to give it up if the evidence is against it. Don't get too attached to your theory.

>I love my theory. Nothing that you have said is mutually exclusive to its accuracy.

 

"The highest authorities in the field in the evolutionary biology havn't concluded any such thing. Read this...

http://www.ucmp.berkeley.edu/vertebr...ht/evolve.html

 

Did you read the article beyond its saying there are a number of hypotheses?

 

For instance, the article states "Scientists generally agree that wings must have been exaptations; they were used by the ancestor for one function, and became useful for flight among the descendants (if they weren't exaptations, then they were adaptations, which would mean that they were wings already used for powered flight; a circular argument).""

>I submit that the forelimb fins adapted to wings after their feathers got longer. Adaption is a change in form. Exaption is a change in function.

 

"How do wings aid diving? They don't! All divers put their forelimbs against their body in order to enter the water. If they don't, then the force of hitting the water breaks the bones!"

>Do you recall I said protobird may belly-in. Lots of birds land on their bellies or feet and don't fold their wings.

 

"Now, did you look at the date of the webpages? If they were written before Dial (as was most of the stuff at the Wiki site, since Dial is the latest reference) then you are getting a controversy that existed in the past. For instance, if you only looked at papers more than 3 years ago, you would see a "controversy" over whether birds evolved from dinos or both birds and dinos had a common reptilian ancestor. That controversy has been settled. The Wiki site uses reference prior to Dial to say what the state of the situation was then -- and then there was a controversy."

>The evolution of dinos to birds is different than the evolution of bird flight! My theory is "The Aerodynamic Origin of Bird Flight" and is available at:

http://protobird.blogspot.com/

 

Enjoy,

 

Art

[foodchain]

>>>Some think the protoavis period ( before archeopterix) might be 75 million years. If the initial area where flight originated is gone, what are we supposed to do?

 

I think you would first have to define the evolution of the bird in various environmental variables. Such as did traits or organisms we would class as birds or close relatives radiate to any great extent or not in relation to what for variables. Such as the extinction that lead to the dinosaurs. Did traits exist that were bird like but of no specific bonus to fitness overall until massive geological change? Were some species simply better at catching fish but still bipedal with no flight capability?

 

As pointed out the fossil record is pretty important, simply with the case of Maniraptora classification. Its so important to even have such so you can ask such questions. I don’t really know how much we can recreate a species lifestyle currently which I think hurts. If you read up on predatory behavior the ability to catch food is basically life for such organisms overall. So if you have traits that lead to an advantage in a giving situation basic evolutionary thought would have such occurring more in frequency giving a population overall. Though I know that you cant use that alone as you have to make such an abstraction more concrete with a species in real life, which for the sake of discussion requires creating very old environments in the earths past including of course behavior of an organism or multiple ones.

[SamCogar]

I have a question.

 

Why does it seem to me that most all discussions on the evolution of “flight” are centered around the increased advantage of acquiring food …… rather than escaping from being eaten as food?

 

And another one, why does it seem to me that said discussion is about the dino (proto-bird) moving fast enough to gain airspeed …… and not entertaining the possibility that the wind provided the required airspeed?

 

The young of most all species have more of a problem keeping from being eaten …… than they do at finding something to eat, right?

[lucaspa]

"Please define ""first incremental success that aided survival"."

> The first use of an anatomical feature aerodynamically, that natural selection will keep.

 

So where is your first use of wings in diving as an aerodynamic feature? As I stated, in diving having forelimbs outstretched is detrimental, not advantageous.

 

"You don't mention exaptation at all."

>Yes I do! Didn't you read this: "The tail is the first exaptation.

 

Not in terms of wings or flight do you mention exaptation. Where is the exaptation for that? You only talk adaptation there.

 

"The running of the birds up inclines is NOT "defensive failure"."

>In Dial's own words, please read within the first paragraph of each:

http://dbs.umt.edu/flightlab/documents/BundleDialJEB2003.pdf

http://www.aibs.org/bioscience-press-releases/resources/s15-0506.pdf

Look for "reach refugia" in the first and "escape performance" in the second.

 

1. You didn't read carefully. In the first: "WAIR has been documented in the juveniles and adults of four species of ground birds, and involves the simultaneous use of flapping wings and running legs to ascend steep inclines (Dial, 2003). WAIR permits extant ground birds, and may have permitted proto-birds, to use their hindlimbs more effectively in retreat to elevated refuges (cliffs, boulders, trees, etc.)."

 

Dial limits his discussion to living ground birds. It is obvious that carnivorous theropod dinos would have used the ability to chase prey.

 

2. Dial is clear it is not a "defensive failure", but at least a "defensive success". Avoiding predators and reaching refuge so that you are not eaten contributes to reproductive success. Of course, we have the problem of your mischaracterization of natural selection into false categories. There are no categories such as you have tried to divide natural selection into "offensive" and "defensive". For natural selection, anything that gives an edge in the competition for survival and reproduction is a "success". A gazelle able to outrun and outturn a lion has a beneficial trait, whether you consider it "defensive" or not.

 

"Let's look at some of what you stated:

"Small wings or fins will be useful only if there is major airspeed to achieve any kind of incremental success.""

> I think I explain this very well, please re-read"

 

Surely you can explain. Telling me to "re-read" is not furthering the discussion. It is a duck.

 

"A headfirst diver will need to control its rotation to keep its aim straight."

 

Humans have no tails but are able to control rotation during headfirst dives. This falsifies the necessity of a tail for a headfirst diver.

 

"Protobird was a diver! Protobird dove for a fish, swam back to shore and climbed back up to the spot from where it dove, and waited for another fish to come by."

"That's a lot of energy to spend for food. That climb takes lots of energy for the distance you are looking at."

>A bank is a short walk from behind.

 

But it still takes more energy than simply wading out into a stream. Remember, most of the attempts are going to end in failure. A wader doesn't have to climb back out when it misses; it just stands there. Therefore diving is going to be selected against in a population living along a bank.

 

Only in a situation where the organism has to go looking for fish in the ocean and then dive on them is diving going to be used. But you need flight to go looking!

 

"Cormorants are that accurate today, but then they fly around looking for fish!

>You have confused Terns for Cormorants.

 

1. No, I didn't. Cormorants dive for fish: http://www.springerlink.com/content/t115v5107mk16065/

http://www.mnh.si.edu/exhibits/natures_best_2006/gallery/cormorantdivingforherring.html (notice the folded wings in the picture)

http://www.britannica.com/bps/topic/137735/cormorant#tab=active~checked%2Citems~checked%3E%2Fbps%2Ftopic%2F137735%2Fcormorant&title=cormorant%20--%20Britannica%20Online%20Encyclopedia

 

2. Even if I made the mistake between cormorants and terns (which I didn't), it doesn't change the validity of the argument. You didn't address the argument. As I said, cormorants fly around looking for fish. The success of their dives (in terms of catching fish) depends on the density of fish. In order for your diving hypothesis to be correct, you would have to have a very constant (over thousands of generations) high density population of fish in a stream. And, of course, you don't get any aerodynamic benefit from having wings to dive from a low bank, do you? If you then move to higher banks and then cliffs, then the ecological requirement for a very dense fish population in a stream adjacent to cliffs (with water deep enough to allow diving) becomes even less likely.

 

3. BTW, did you notice that cormorants do NOT have tails? So tails are not necessary for controlling a dive. By your theory, the first birds would have been tail less. However, the fossil record shows that to be in error.

 

"This new technique would be mimicked by others, maybe the young."

 

"Mimicking isn't part of natural selection."

>Then how do aquire an instinct?

 

By natural selection. Having a genetically controlled behavior contributes to survival and differential reproduction. For instance, humans have an instinct for suckling. The babies born without the alleles for that behavior did not nurse and starved to death. OTOH, babies with the alleles nursed and survived: to have babies that, due to inheritance, also had the alleles.

 

"For natural selection to work the diver must get more food than those that don't. Therefore have more children to pass the alleles for diving to. More children that have alleles for diving than there are children of non-divers."

>Huh? Traits that work produce more offspring.

 

Why do "traits that work produce more offspring"? You have to show a mechanism by which a trait is going to result in more offspring. IOW, why and how the "trait" works. In your case, the how must be: the diver gets more food than those who don't. However, in the case of a meandering stream with banks, a wader will get more food than a diver and at less energy expenditure.

 

Extending one's hunting range is instictive.

 

No, it's not. And we are not talking about "extending a hunting range". We are in the same range but talking about which is more efficient at getting food: diving or wading.

 

"Protobird would expand its wading area by adding the edges and the areas that were normally bypassed where the water was too deep."

 

That won't work. Remember, according to your theory, the deep water must be close to the bank. Look at rivers. That doesn't happen all that often. It is still more efficient to walk to where the water is shallow enough to wade and then simply go stand and lunge at fish than dive and climb out again.

 

"As I said, you put a lot of thought into this. But when you propose a theory, then you have to be prepared to give it up if the evidence is against it. Don't get too attached to your theory.

>I love my theory.

 

As a scientist, you can't do this. Because your job is to show the theory to be wrong. Science works by showing theories to be wrong. If you "love" your theory, you won't be willing to do your job as a scientist.

 

1. C Seife, Radical gravity theory hits large scale snag. Science 292: 1629, June1, 2001 MOND (modified Newtonian dynamics) alters some properties of gravity to eliminate the need for dark matter, but doesn't fit with General Relativity. Recent observations show it is at odds with observationsof galaxy clusters. "Missing" peak in CMB thought support for MOND, but peak found. The data "disagree very strongly with MOND's prediction," says Aguirre. "MOND is not a viable alternative to dark matter in clusters." "As its inventor, I would like it [MOND] to be a revolution, but I look at it coolly," says Milgrom. "I will be very sad, but not shocked if turns out to be dark matter." Milgrom is a damn good scientist.

 

Nothing that you have said is mutually exclusive to its accuracy.

 

Several pieces of data I have mentioned (and more I will say) are contradictory to its accuracy.

 

I submit that the forelimb fins adapted to wings after their feathers got longer.

 

What "forelimb fins? There are no "fins" in the fossil record in the evolution of birds. The forelimbs of bird ancestors are grasping limbs with claws at the ends, not fins.

 

Adaption is a change in form. Exaption is a change in function.

 

And the bones and soft tissue show there wasn't a change in form of the forelimb. The forelimbs of Archeopteryx are identical to those of small dinosaurs -- so identical that fossils without feather impressions were misidentified as celiosaurs.

 

"How do wings aid diving? They don't! All divers put their forelimbs against their body in order to enter the water. If they don't, then the force of hitting the water breaks the bones!"

>Do you recall I said protobird may belly-in. Lots of birds land on their bellies or feet and don't fold their wings.

 

They don't dive, they float! You said it yourself, "lots of birds land". Your theory requires wings to be used in diving. Name a diving bird that dives with its wings unfolded to aid diving.

 

"Now, did you look at the date of the webpages? If they were written before Dial (as was most of the stuff at the Wiki site, since Dial is the latest reference) then you are getting a controversy that existed in the past." ... The Wiki site uses reference prior to Dial to say what the state of the situation was then -- and then there was a controversy."

>The evolution of dinos to birds is different than the evolution of bird flight!

 

That's not the point. The point is that what was a controversy in the past may not be a controversy now. Your sources are all older than Dial's papers -- which has settled the controversy. Therefore, when those sources were written, there was a controversy. Now, new data has resolved the controversy.

 

My theory is "The Aerodynamic Origin of Bird Flight" and is available at:

http://protobird.blogspot.com/

 

I know. I've been quoting from it, remember? Try to keep up. The theory doesn't work for several reasons. I'm sorry. I know you "love" it, but that doesn't change the data that falsifies it. As you admitted, you did the theory without even looking at the paleontological data.

 

Consider something else: catching fish with the mouth requires adaptations to the jaws and teeth. Early birds and the theropod dinos that are their ancestors don't have those adaptations. And this is even more surely known because pteranodons and pterosaurs had those adaptations. In fact, at the time birds were evolving, pterosaurs and pteranodons occupied the very niche you are proposing for protobirds: diving after fish! With many genera and families already adapted to that ecological niche, there is no way an early diving protobird could have competed. Another falsification of your theory. Again, sorry. You put a lot of work into it. Too bad it doesn't work.

 

I have a question.

 

Why does it seem to me that most all discussions on the evolution of “flight” are centered around the increased advantage of acquiring food …… rather than escaping from being eaten as food?

 

Because the ancestors of birds were carnivorous dinosaurs. Therefore they are the ones doing the eating. Although, as small carnivorous dinos, they could have been prey to larger carnivorous dinos, thus Dial's discussion of using running up an inclined plane to reach a "refuge" and avoid being eaten.

 

And another one, why does it seem to me that said discussion is about the dino (proto-bird) moving fast enough to gain airspeed …… and not entertaining the possibility that the wind provided the required airspeed?

 

Because wind is not constant enough nor from the right direction to provide a selection factor. Remember, for the wind to provide the airspeed, it must be blowing toward the animal. What if the prey or refuge is downwind? IOW, nearly all the time the animal is going to need to move in a direction where the wind won't be able to provide the required airspeed. In order for the trait to be reliable enough for natural selection, it must work in all conditions.

 

The young of most all species have more of a problem keeping from being eaten …… than they do at finding something to eat, right?

 

In birds, however, feathers for flight don't develop until the bird is an adult. This is the strength of Dial's work: the feathers have an evolutionary advantage even if they don't get the animal off the ground. So they protect a young bird (and even an adult protobird) from being eaten even when they are not good enough for flight.

[Protoart]

Thanks for bumping the thread. Lets keep the discussion of my theory of "The Aerodynamic Origin of Bird Flight" going. Which is available at: http://protobird.blogspot.com

 

Lucaspa wrote: (why, I do not know!)

 

"So where is your first use of wings in diving as an aerodynamic feature? As I stated, in diving having forelimbs outstretched is detrimental, not advantageous."

 

I write:

>The first use of "wings" follows the first use of "fins" which were for the purpose of guidance.

 

"Not in terms of wings or flight do you mention exaptation. Where is the exaptation for that? You only talk adaptation there."

 

>I guess you finally read that section.

 

"Dial is clear it is not a "defensive failure", but at least a "defensive success". Avoiding predators and reaching refuge so that you are not eaten contributes to reproductive success. Of course, we have the problem of your mischaracterization of natural selection into false categories. There are no categories such as you have tried to divide natural selection into "offensive" and "defensive". For natural selection, anything that gives an edge in the competition for survival and reproduction is a "success". A gazelle able to outrun and outturn a lion has a beneficial trait, whether you consider it "defensive" or not.

 

>Defensive success comes passively. Offence is trial and error. How does a stalked animal evolve better sight, hearing, smell or camoflage to escape being eaten. The old and slow are eaten first. Survival of the fittest rules.

 

"Humans have no tails but are able to control rotation during headfirst dives. This falsifies the necessity of a tail for a headfirst diver."

 

>Humans in no way can control rotation after they left the diving board or platform. Are you blind?

 

"But it still takes more energy than simply wading out into a stream. Remember, most of the attempts are going to end in failure. A wader doesn't have to climb back out when it misses; it just stands there. Therefore diving is going to be selected against in a population living along a bank."

 

>Nonsense, If the fish won't come you, you have to go to them. Zebras don't come to the lion.

 

"Only in a situation where the organism has to go looking for fish in the ocean and then dive on them is diving going to be used. But you need flight to go looking!"

 

>As I wrote there are many places where you can see fish from the shore.

 

"Cormorants dive for fish"

 

>Cormorants swim on the surface and dive to bottom looking for fish. Terns dive from above for fish they can see.

 

"Even if I made the mistake between cormorants and terns (which I didn't), it doesn't change the validity of the argument. You didn't address the argument. As I said, cormorants fly around looking for fish. The success of their dives (in terms of catching fish) depends on the density of fish. In order for your diving hypothesis to be correct, you would have to have a very constant (over thousands of generations) high density population of fish in a stream. And, of course, you don't get any aerodynamic benefit from having wings to dive from a low bank, do you? If you then move to higher banks and then cliffs, then the ecological requirement for a very dense fish population in a stream adjacent to cliffs (with water deep enough to allow diving) becomes even less likely."

 

>The American Bald Eagle takes a fish with its talons one fish at a time. Birds take more tonnage of aquatic animals than they take in seeds, fruit, rodents, insects, etc.

 

"BTW, did you notice that cormorants do NOT have tails? So tails are not necessary for controlling a dive. By your theory, the first birds would have been tail less. However, the fossil record shows that to be in error."

 

>Cormorant have tails. You are blind (sorry)!

 

You wrote: "Mimicking isn't part of natural selection."

I wrote: "Then how do aquire an instinct?"

You wrote "By natural selection."

>???

 

I'm not going to respond to anymore of your statements. You are completely incoherant.

 

BTW, Ken Dial sent me his new paper in "Nature". If you send me your email address I'll send it to you. He no longer refers to why OTW/WAIR was necessary, just "locomotive behavoir". My email address is protoart@gmail.com and is on the bottom my blogpost at: http://protobird.blogspot.com

 

P.S.

The first aerodynamic success that aided survival and that natural selection will promote is "bank diving." No other theory has a cogent initial act. Try challenging my premise.

 

Art

[CaptainPanic]

I always wonder whether the pointy nose of birds means that they plan to evolve into supersonic birds one day.

 

(I'm very sorry... I'll keep the number of stupid posts limited).

[SamCogar]

Originally Posted by SamCogar

 

Why does it seem to me that most all discussions on the evolution of “flight” are centered around the increased advantage of acquiring food …… rather than escaping from being eaten as food?

 

Because the ancestors of birds were carnivorous dinosaurs. Therefore they are the ones doing the eating. Although, as small carnivorous dinos, they could have been prey to larger carnivorous dinos, .....

 

Well now Lucas, if that is the "why" answer to my question then maybe the researchers on the "evolution of flight" should really get out of that "rut" and consider a different "road" to explore.

 

.... thus Dial's discussion of using running up an inclined plane to reach a "refuge" and avoid being eaten.

 

(Sam) why does it seem to me that said discussion is about the dino (proto-bird) moving fast enough to gain airspeed

 

Because wind is not constant enough nor from the right direction to provide a selection factor. Remember, for the wind to provide the airspeed, it must be blowing toward the animal. .....

 

Yes Lucas, ..... and you should remember that ... using running up an inclined plane to reach a "refuge" and avoid being eaten ..... there has to be inclined slopes everywhere and those proto birds always had to be at the bottom of them when the predator came running.

 

Lucas, I would think that the "wind" along the shores of lakes and oceans could be depended on as a reliable aid for excaping a predator ..... moreso than always being at the bottom on an inclined plane of some sorts.

 

In birds, however, feathers for flight don't develop until the bird is an adult. This is the strength of Dial's work: the feathers have an evolutionary advantage even if they don't get the animal off the ground. So they protect a young bird (and even an adult protobird) from being eaten even when they are not good enough for flight.

 

Are you saying that feathers are better protection from ground based predators than are scales? If so, please explain.

 

An ostrich has feathers, .... so what "evolutionary advantage" do said feathers afford them from being eaten by predators?

 

Lucas, in several species those non-flight "fuzzy feathers" are useful in just getting the young birds ..... to the ground without being killed in their decent.

 

Lucas, I question many of the "accepted" beliefs concerning some of the evolved traits and physical features of specific species such as "bird flight" and "human origin environment". aka: I am a proponent of the Aquatic Ape Theory and to paraphrase a famous quote, "Nothing makes sense about H sapiens evolution other than a water environment".

 

I question said "accepted" beliefs because it seems to me that many researchers pick a “trait or feature” of a specific species and then “look backwards” to resolve from whence it evolved, ….. rather than, …… starting back in time and “looking forward” to resolve how it might have evolved.

 

A proto bird evolving feathers for flight because of a needed advantage for running up an inclined slope is “looking backward” to justify a predetermined conclusion.

 

Mutations, the primary “driving force” of evolutionary changes, …… are random and unplanned or accidental if you chose to note them as said. They are neither “good” nor ”bad” unto themselves, but only to the “life form” in which they occur with “good” meaning advantageous, etc.

 

Thus, mutations do not occur because of a “need based” change (running up a slope) that benefits the “life form”, ….. but rather the “life form” benefits by taking advantage of the changes caused by the mutation.

 

Thus, stating or implying a mutation is a “need based” change is again “looking backward” to justify a predetermined conclusion.

 

And those who are always “looking backwards”, …. are usually afraid of “losing their way” ….. and never seem to make much forward progress.

 

cheers

[iNow]

It appears there two main ideas. 1) Dinos from the ground up ran and sooner or later began flying. 2) Dinos from the trees became ever more efficient at gliding, until they could fly.

 

I personally don't find the two ideas mutually exclusive, and personally believe that flight evolved via both paths.

 

Either way, NOVA last night had a great special on this very issue. Click the link below to watch it for free online.

 

 

The Four-Winged Dinosaur:

 

http://www.pbs.org/wgbh/nova/microraptor/program.html

[Protoart]

Reply to iNow

 

The NOVA show realy didn't discuss the "ground-up" or "tree-down" origin of flight. The show was about the use of the leg feathers on "microraptor." The conclusion was that the legs held straight back gave a good lift to drag ratio and that the splayed out leg position was a mistake.

I still belive the the origin of flight was "bank jumping" because the trial and error failure of diving is not harmful and explains the fisrt exaptation, the aerodynamic use of the tail. This theory is also not mutually exclusive to what was demonstrated on the show.

[Robert Byers]

First timer here. I am a biblical creationist.

I saw the Nova show and recommend it to creationists and all free thinkers.

It showed how on bare details frozen in rock great conclusions of living flight are made. It showed how when evolutionists disagree they have no problem questioning the motives and "science" of the others. In fact in the whole show no "scientific method" was shown to be applied. Just guessing. This is a good example of how the whole concept of evolution is held up. Hypothesis without testing.

The creature found is probably just a variety of something else and not a missing link. All this jump, jump, jump, till you stay aloft is unlikely and even on the surface impossible. Flight is a original state created by God.

Robert Byers

Toronto,Ontario

[iNow]

Flight is a original state created by God.

 

Robert,

 

You have to know how silly you sound when you say such a thing.

[Edtharan]

In fact in the whole show no "scientific method" was shown to be applied.

What you must remember is that a TV show has only around 1 hour, but the scientists involved in these theories have spent lifetimes gathering data, analising it, and developing their explainations. Trying to condense all thiat into a 60 munite show that is intended to entertain the watchers first is going to have to leave something out.

 

Just because a TV show can't explain an extremely complex and involved idea along with centruies of collected data in 60 minutes does not mean that the concepts the show was trying to get across is necessarily wrong or incomplete (or just geussed at).

 

It showed how on bare details frozen in rock great conclusions of living flight are made.

If there is a fossilised feather, then you can conclude that there were feathers around. The scientists, when they look at the "bare details frozen in rock", the are doing no more than this. Of course they are looking at much more than just "feathers".

 

If a fossil has a bone structure (with feathers) that is the same (or similar) to the wing and other flight structures (the keel bone and the wish bone) of flighted birds, then you can conclude that flight was possible (as the keel bone is large because that is where the muscles that power the wings are attached to).

 

So if you find a fossil that has a large keel bone, wish bone and feathers, but has a reptilian head and tail, then this would be something that is not quite a bird (it has feathers) and is not quite a reptile. It would infact be something inbetween. A missing link if you will.

 

Well they have several fossils like this (Archaeopteryx is one). Remember, even if all they had was a single fossil, it is absolute proof that that organism actually existsed. And they have several of them covering several differnet species (some closer to being a reptile and some closer to being a bird).

 

This is a good example of how the whole concept of evolution is held up. Hypothesis without testing.

This is just a barely disguised "God of the Gaps" argument (actually it is just an attempt to create support for it). When scientist showed that the skeletal structure of several dinosaur species (the Therapods) were very similar to that of Birds, creationists jumped up and said: "But where is the fossil that is half way between Dinosaurs and Birds!".

 

Scientists agreed and said that if their theories are correct then there will be a species that existed that is not quite a dinosaur and not quite a bird.

 

Well a few years later the Archaeopteryx fossil was discovered and this Observation supported the scientits theories (and gave the answer tha tthe creationists were asking for).

 

But now the creationists are asking for fossils somewhere between Archaeopteryx and Dinosaurs (or Birds). It is the same God of the Gaps argument all over again. Where will the God of the Gaps stop?

 

The fossil record is incomplete. Not all animals get fossilised. In fact fossilisation is extremely rare, so not all species get even 1 fossil to their name.

 

The original arguemnt by creationists has been answered. We have fossils that show a link between Dinosaurs and Birds.

 

What we don't have is the set of fossils that allow us to create a flip book showing exactly how dinosaurs actually achieved flight. But we do know it occured because of Archaeopteryx.

 

When the creationists ask: "But show us the fossil of the creature that shows how Dinosaurs achieved flight", what they are really asking is: "Show us the fossil that lies exactly halfway between Dinosurs and Archaeopteryx". Inother words there is a gap, so God must have filled it.

 

Now that was the God of the Gaps dismissed on Scietific ground, how about Religious grounds?

 

Well, for you to claim that God did or Did not do something is skirting around blasphemy. In effect, you are passing Judgement on God.

 

Doesn't it say in the Bible: "Judge not least you will be Judged yourself?" And passing that judgement on God would be seen as blasphemy.

 

But, let us assume that you are right and that God did create everything as it is. Why then did God decide to place fossil that would make us doubt His word. It can't be because he is testing our faith, He is supposed to be all knowing so he already knows our faith and so he would not need to test it.

 

God is also supposed to be benevolent and love us. But by placing fossils it casts doubt on His existance and leads many to reject Him as false. But He punishes us for this rejection (with ETERNAL torture ).

 

Does that sound like someone who loves you? What if this was another person that did this to you. What if they deliberatly planted evidence that would lead you into one action, and then when you took that action they tortured you for taking that action?

 

Would you considder that person to love you, would you considder them benevolent?

[CDarwin]

I saw the Nova show and recommend it to creationists and all free thinkers.

 

Every free-thinker I know makes a habit of denying wholesale scientific knowledge on the basis of the blind acceptance of unsubstantiated, ancient texts written for a different purpose.

 

Now that was the God of the Gaps dismissed on Scietific ground, how about Religious grounds?

 

Well, for you to claim that God did or Did not do something is skirting around blasphemy. In effect, you are passing Judgement on God.

 

Doesn't it say in the Bible: "Judge not least you will be Judged yourself?" And passing that judgement on God would be seen as blasphemy.[/Quote]

 

Perhaps a better way to address this would be to point out that a God of the Gaps is just another word for "The Incredible Shrinking God." If your belief in God is based on the assumption that he is necessary to fill some or another gap in our knowledge, then you set yourself on a very precarious ledge, What happens if that gap is filled? Well then you can either A)accept that and move on to another gap, which just puts you on the same ledge as before, B)suffer a diminished perception of God or a lose of faith, or C)reject that the gap has been filled at all and turn your back on science. Your faith, if it continues at all, becomes one of fleeting foundations or out-right denial. Just my take on the matter.

 

But, let us assume that you are right and that God did create everything as it is. [...] Would you considder that person to love you, would you considder them benevolent?

 

I don't think that's going to win our Creationist friend over. What he's more likely to say is that the transitional bird fossils are all genetically distinct and immutable "kinds." What I would like to ask him is to provide any evidence that such "kinds" genuinely exist in nature.

 

 

Anyway, as to the topic of bird evolution, my gut says that Microraptor might turn out to be a collateral ancestor of birds outside the actual line of descent. Adaptive radiations tend to result in a proliferation of lineages. But now that's just a guess.

[Robert Byers]

Thank you to both posters. However I was not addresing the creatures place.

I was pointing out the most pregnant fact here. The lack of the scientific method being used to draw conclusions. With that also two gangs of evolutionists attacking each other as not doing science while both claiming to do it. They questioned each others motives and how these motives were making them wrong. Their conclusions were not testable and so both sides stayed stubborn in their positions. As a creationist I always find this in evolution. Guessing masquerading as science. When two or more groups disagree the reality of this guessing is revealed. This nova episode is case in point. In fact its amazing that evolutionists making the show don't realize the blunder.

Robert Byers