Could Birds Re-evolve Arms?

[Dekan]

Modern birds have had their front legs, or what might be called their "arms", converted into wings.

These wings are obviously essential to those birds which need to fly.

 

But flying is not something all birds do. Some spend all their time walking about on the ground - eg, chickens.

Chickens don't seem to have much use for wings. Apart from an occasional fluttering jump, their wings are just unnecessary encumbrances.

 

Could these encumbrances be converted back into useful arms?

A pair of manipulative arms, would surely be a much better survival asset, than a pair of almost redundant wings.

 

Is there any sign that chickens, or any other flightless birds, are evolving arms again - if not, what stops them from doing it?

[Stefan-CoA]

Give it a few million years and appropriate selective pressures and I'm sure this would be possible.

 

Thing is, even if chickens have no use for their wings it's most likely only because humans prevent them from flying. I'm not sure but I think chickens can still fly to a degree. And if there is a wing/arm cross-over chicken, not much will come of it because who would want to eat their flesh/eggs and it will probably be culled. If chickens were to live free though...

 

Furthermore, I doubt there is any observable change just yet, we've only been cultivating chickens for a few thousand years at most, far too short a time for any such changes to make themselves observable.

[ydoaPs]

No. Evolution is a lie from Satan to draw you away from God.

[lemur]

If chickens don't have arms and hands, then where do chicken fingers come from?

[pwagen]

I'm not sure but I think chickens can still fly to a degree.

Having grown up with a mother who cultivated chicken, I can confirm this. They can't, for instance, fly south for the winter, but they can extend their jumps by quite a bit by flapping their wings. I once heard a rumor of a chicken who had its head chopped off, and its death-throes caused it to fly up and land on the roof of the barn.

 

But maybe that was a bit too much info.

 

As for re-evolving arms, I think it depends on which bird it is. An ostrich, for example, can't fly and really doesn't use its wings for anything as far as I know. When it comes to those, I can imagine there's pretty much no evolutionary advantage to having arms.

 

But then we have the penguin. I'm not sure if it uses its wings for swimming, but even if they don't, they're using it to shove their kids around, and keep those warm. I'm no expert, but I can see some potential there. But I guess they're as likely to evolve fins.

[Moontanman]

Having grown up with a mother who cultivated chicken, I can confirm this. They can't, for instance, fly south for the winter, but they can extend their jumps by quite a bit by flapping their wings. I once heard a rumor of a chicken who had its head chopped off, and its death-throes caused it to fly up and land on the roof of the barn.

 

I can confirm that a chicken that has it's entire set of flight feathers can fly quite well, a couple miles at least and then there was mike the headless chicken that lived 18 months with it's head cut off

 

http://www.miketheheadlesschicken.org/story.php

 

As for re-evolving arms, I think it depends on which bird it is. An ostrich, for example, can't fly and really doesn't use its wings for anything as far as I know. When it comes to those, I can imagine there's pretty much no evolutionary advantage to having arms.

 

Bipedal dinosaurs, the largest ones anyway, seemed to be heading in the evolutionary "direction" of having no arms at all, almost half of T-Rex's "arms" were inside his body... I'm not sure if a body function so throughly lost as a birds "hands" can be re-evolved, i wouldn't expect to see whales re-evolve limbs from their fins.

 

But then we have the penguin. I'm not sure if it uses its wings for swimming, but even if they don't, they're using it to shove their kids around, and keep those warm. I'm no expert, but I can see some potential there. But I guess they're as likely to evolve fins.

 

Penguins swim with their wings much like other birds fly, they do indeed fly under water and they can out swim many fishes, their wings are very fin like in appearance but are still wings.

[insane_alien]

it wouldn't be evolution working backwards (that concept is inherently false) but rather a form of convergent evolution, it would arrive at new arms from a different direction than the initial evolution.

 

the new arms would have more wing like features than arms evolved without going through wings.

Edited April 30, 2011 by insane_alien

[SMF]

Yes, a modern bird could evolve such that their wings became useful front legs or arms, but I can't think of a reasonable circumstance in which there would be selection pressure for this to be advantageous and that would also be simultaneous with an open ecological niche not already occupied by an existing critter. If one had a very wealthy family with the interest in a multigenerational project, this could be accomplished in the lab with artificial selection. You could create a pool playing chicken and charge $5 per game at the county fair. SM

[ydoaPs]

it wouldn't be evolution working backwards (that concept is inherently false) but rather a form of convergent evolution, it would arrive at new arms from a different direction than the initial evolution.

 

the new arms would have more wing like features than arms evolved without going through wings.

One could say that they're the same arms if the evolution of the arms was a transition from wings to arms since a lot of the structure is still there from the last time the wings were arms and presumably that structure would remain in the new arms.

[xxSilverPhinxx]

If chickens don't have arms and hands, then where do chicken fingers come from?

 

 

***

As for the question:

 

I don't think it would be an example of reverse evolution, or "de evolution", but a new molding of a limb they already have if there were selective pressures that favour the remolding.

Edited July 2, 2011 by xxSilverPhinxx

[raptorbrain]

birds are not reptiles. they did not evolve from dinosaurs. dinosaurs are still alive. we, as humans, killed them.

[Moontanman]

birds are not reptiles. they did not evolve from dinosaurs. dinosaurs are still alive. we, as humans, killed them.

 

 

Care to back that up with some evidence other than your raptorbrained assertion?

[questionposter]

A bird randomly develops a limb in place of wings which have two fingers on them which don't work super great, but all the other arm joints are the same. It turns out this is fine as it can still find food with its powerful sense of smell and put it in its mouth with its fingers as well as break things with its beak. Its successful, and then in a couple hundred thousand years, a bird like this one comes along only it randomly develops 3 fingers, and that works out fine. Another couple more hundred thousand years have passed and random changes in the wrist bone structure lead to a bird that can grasp things making it even more successful. Etc.

Edited September 28, 2011 by questionposter

[kitkat]

Since we have no idea what the environment will be like in the future, there is nothing in the way that birds could not grow arms or anything else for that matter, it depends on their environment if they managed to survive until then.