Why didn't animals evolve wheels?

[pErvinalia]

We've already dealt with this. It's not impossible.

[mistermack]

We've already dealt with this. It's not impossible.

Working on the principle that nothing is impossible, who could argue?
If possibility is a progression, from black to white, then somewhere in that fuzzy line, you will always be able to argue that something is possible, It's just a question of how unlikely, in the end.

Animals evolving wheels is so far along the line towards impossible, that you might just as well call it impossible. It was never going to happen.

The problem of blood supply wouldn't matter to an internal wheel. Like a rotary heart. If anything was going to evolve a spinning mechanism, you would think that a rotary blood pump would be it. But nothing like it has happened as far as I know. Mainly because what is already there is better anyway.

The same goes for an external wheel. It's only going to happen for a land animal. Fishes etc don't need a load-bearing axel anyway. Their weight is pretty much neutralised by bouyancy.

On land, where would a wheel actually be of benefit? To make the wheel useful, we had to make roads, or rails. Animals don't do that kind of stuff.
Small animals have no need of wheels anyway. A wheel is great for carrying a heavy load, but small animals are much stronger for their size, that they have no need of it.

Bigger animals would have the same problem as we had. They would need a road or rail, to make the wheel useful. And a big brain to work around the problems that wheels encounter.

[pErvinalia]

Nothing in that refutes anything I've said. The simple fact is, legs appear to be a highly functional and useful way of getting around.

[Brian Peacock]

As for countering the possible misapprehension that no such evolutionary process would or could take place because of the bio-mechanical impossibility of maintaining circulatory and nervous systems, yes, someone might possibly entertain such a misapprehension, but so far nobody seems to in this thread, and I certainly don't either. You keep repeating yourself as if someone has.

The reason being the inherent difficulty in creating a biological system involving a wheel that doesn't get the mechanisms for feeding and getting rid of waste product, and nervous system, all tangled up when the wheel spins.

[Hermit]

As for countering the possible misapprehension that no such evolutionary process would or could take place because of the bio-mechanical impossibility of maintaining circulatory and nervous systems, yes, someone might possibly entertain such a misapprehension, but so far nobody seems to in this thread, and I certainly don't either. You keep repeating yourself as if someone has.

The reason being the inherent difficulty in creating a biological system involving a wheel that doesn't get the mechanisms for feeding and getting rid of waste product, and nervous system, all tangled up when the wheel spins.

"no such evolutionary process would or could take place" I was focusing on the bolded word when I wrote the post. Since then JimC got pretty close to saying just that.

[JimC]

As for countering the possible misapprehension that no such evolutionary process would or could take place because of the bio-mechanical impossibility of maintaining circulatory and nervous systems, yes, someone might possibly entertain such a misapprehension, but so far nobody seems to in this thread, and I certainly don't either. You keep repeating yourself as if someone has.

The reason being the inherent difficulty in creating a biological system involving a wheel that doesn't get the mechanisms for feeding and getting rid of waste product, and nervous system, all tangled up when the wheel spins.

"no such evolutionary process would or could take place" I was focusing on the bolded word when I wrote the post. Since then JimC got pretty close to saying just that.

My extremely important proviso when I stated that it simply could not happen, was that it could not happen as an evolutionary branch deriving from quadruped land vertebrates. Starting from a very different body plan on an alien planet would be another kettle of fish, although still highly unlikely, IMO...

[Hermit]

Yes, Jim. That is why I wrote you "got pretty close to saying just that."

Besides, you did say "that it could not happen as an evolutionary branch deriving from quadruped land vertebrates." Your reasoning is based on the "because it never happened in the past it can never happen in the future" fallacy. Did you forget about the Problem of Induction? Though in reality massively unlikely, I would not in principle exclude the possibility of a quadruped evolving with wheels.

[JimC]

Yes, Jim. That is why I wrote you "got pretty close to saying just that."

Besides, you did say "that it could not happen as an evolutionary branch deriving from quadruped land vertebrates." Your reasoning is based on the "because it never happened in the past it can never happen in the future" fallacy. Did you forget about the Problem of Induction? Though in reality massively unlikely, I would not in principle exclude the possibility of a quadruped evolving with wheels.

I stand by my contention that a powered wheel organ is a physical impossibility for an organism based on the vertebrate bauplan.

[Brian Peacock]

I actually agree with you Jim, and your provisos are important ones, and relevant ones. From what we know about our own biosphere an organism developing a wheelish appendage seems highly unlikely - perhaps unlikely enough to be indistinguishable from impossible. Nonetheless, the reason I embarked upon this massive quibble was to reinforce evolution as seen in the wild and in the lab, as a an unguided, goal-less process without 'design constraints', beyond those placed on any generational iteration of an organism by their genome and/or their environmental circumstances. The possibilities of evolution are limited by our capacities to imagine. After all, who would've imagined that fish would develop fins into legs, gills into lungs eh, scales to plates to hide to fur to skin, and after all that invent Country music (and by so doing sow the seeds of their own destruction)?


I rest my case.

[Brian Peacock]

-- correction...

The possibilities of evolution are not limited by our capacities to imagine.

[JimC]

-- correction...

The possibilities of evolution are not limited by our capacities to imagine.

Yes, but that does not mean that there are no limitations to the evolutionary trajectories available to the descendants of any given branch of the Tree of Life...

[Brian Peacock]

-- correction...

The possibilities of evolution are not limited by our capacities to imagine.

Yes, but that does not mean that there are no limitations to the evolutionary trajectories available to the descendants of any given branch of the Tree of Life...

Well, yes and no. As you said before, 'we can't get to there from here' - but we might get to there from somewhere else we can get to.

Not saying that you are, but we shouldn't necessarily regard evolution as a process of development and/or refinement from relatively unsophisticated to relatively sophisticated states, that evolution only has one direction as it were, from the simple to the increasingly complex, even if what we know of our own genetic history and the genetic history of our biosphere might suggest that kind of narrative arc.

This might be the story at the level of the biosphere, so far, but we should remember that the evolutionary drivers are the genome and the environment, and traits which ultimately don't directly benefit the propagation of the genome, that are ultimately detrimental to the survivability of the species as a whole, may be dropped over time. Evolution is the genome's solution to the challenges of the environment and therefore it's a process constrained by genomic and environmental circumstance. So if that environment changes either the organism has the genomic resources to evolve and meet that challenge or it doesn't and goes extinct. There's no reason then that an organism can't or won't 'devolve' as it were, from a relatively sophisticated to a relatively simpler form, and then perhaps, after sliding back down the tree of life a bit, find a new kind of stasis point or another branch to follow.

But besides the environment and the genome the ultimate constraints are physical laws and the availability of fundamental resources - chemical elements etc - and the rather deterministic interplay of the two, so evolution is not a unconstrained process by any means. All we can say is that once evolutionary processes are under way this is how we've observed them operating on Earth. This is why I find the idea of the possibility of life on Titan or passing comets or in other solar systems so exciting and tantalising, because as yet we have no firm conclusions about the conditions which resulted in our biosphere or the possible ubiquity, or otherwise, of evolutionary process in the wider cosmological environment. In effect, we only have one data point, Earth, and as rich as that data point is it is still only one data point.

More data, we need more data!!

[mistermack]

Anyway, the thread question has been well answered.

The primitive wheel has no advantage for any animal that ever existed, without adding higher technology.
And the route to developing one is prohibitively difficult anyway.

[Jason]

But, related to the wheel, is the rotor which, when combined with blades (or 'wings'), would surely provide a more efficient means of propulsion through the air for the likes of insects and birds which have a 'hovering' flight mode. A hummingbird with a pair of rotating wings would be far more energy efficient in flight than our current model with its extremely complex, and therefore wasteful, rapid 'beating' motion - at best the current mode for the hummingbird is 50% energy efficient as the upstroke of the wing serves no purpose other than resetting the position of the limb in its socket so it may deliver thrust once again.

[Brian Peacock]

I think jet engines are a better idea.

http://m.phys.org/news/2015-04-analysis ... nsive.html