Evolving the wheel

[cowiz]

Phillip Pullman came up with a creature that evolved to use a seed as a wheel.

From the Wikipedia page

The Mulefa evolved in a radically different fashion from humans. These elephant-like creatures possess an anatomy based on a diamond-framed skeleton lacking a spine, have four legs, short horns, and a prehensile trunk that functionally takes the place of hands. Signing with the trunk is an integral part of Mulefa language. They form close-knit communities, closer than most human groups met in the novel. One of the reasons for the closeness of their communities is that, lacking two hands, it usually requires two or more Mulefa trunks working together to accomplish complex tasks like tying knots.

A notable feature of the Mulefa is their use of large, disc-shaped seed pods from their world's enormous "seed-pod trees" in locomotion; the pods fit neatly onto a spur on their front and rear legs when each zalif is grown enough to use it. They propel themselves using their two side legs, like a cyclist without pedals. Ancient lava flows solidified into smooth rivers of rock running across the land serve as roads to ease transport. The Mulefa have a symbiotic relationship with the seedpod trees - their use of the pods on the "roads" allows the extremely hard exterior to crack and the seeds to emerge. These are germinated by the Mulefa, allowing the wheel-pod trees to survive. As the book notes, it is the three combined elements of seed-pod, spur, and rock formation which leads to the current Mulefa existence.

From "The Subtle Knife" - the poorest in the trilogy IMHO

[Coito ergo sum]

Only if having a wheel, rather than limbs, has a survival advantage.

Well, and only if having part of a wheel has a survival advantage. Wings evolved because having partial wings provided survival advantages until eventually gliders became wings. It's hard to envision a use for 1/2 a wheel, although there is a use for 1/2 a wing (breaking falls, gliding, etc.).

But, also, a full wheel is not all that great unless surfaces are smooth and flat. Wheels work well for humans because we modify the landscape.

[devogue]

Imagine it - "look at the wheels on her!"

And her fuckin' gearbox!

[cowiz]

Imagine it - "look at the wheels on her!"

And her fuckin' gearbox!

Meh I'm neutral

[devogue]

Imagine it - "look at the wheels on her!"

And her fuckin' gearbox!

Meh I'm neutral

I've got the horn.

[Bella Fortuna]

Imagine it - "look at the wheels on her!"

And her fuckin' gearbox!

Meh I'm neutral

I've got the horn.

And too much drive.

[owtth]

Imagine it - "look at the wheels on her!"

And her fuckin' gearbox!

Meh I'm neutral

I've got the horn.

And too much drive.

and too many spare tyres.

[Coito ergo sum]

Does that thing have a Hemi?

[Pappa]

Interesting question.
I can't think of a circumstance where it could evolve through natural selection, since it hasn't already.

It has several times. The main constrain is blood flow (or fluid transfer) to the moving part. In all cases where it has evolved, the scale was small enough that the fluid issue wasn't a problem.

Stephen J. Gould wrote a good essay on it from what I remember.

[AshtonBlack]

Interesting question.
I can't think of a circumstance where it could evolve through natural selection, since it hasn't already.

It has several times. The main constrain is blood flow (or fluid transfer) to the moving part. In all cases where it has evolved, the scale was small enough that the fluid issue wasn't a problem.

Stephen J. Gould wrote a good essay on it from what I remember.

At the macro scale?

[Rum]

Interesting question.
I can't think of a circumstance where it could evolve through natural selection, since it hasn't already.

It has several times. The main constrain is blood flow (or fluid transfer) to the moving part. In all cases where it has evolved, the scale was small enough that the fluid issue wasn't a problem.

Stephen J. Gould wrote a good essay on it from what I remember.

At the macro scale?

'Advantage' would be the key - and its hard at the macro level to see how it could be. As someone said earlier - not enough flat surfaces where proto-wheels could offer an escape - or advantage of some other kind.

[Pappa]

Interesting question.
I can't think of a circumstance where it could evolve through natural selection, since it hasn't already.

It has several times. The main constrain is blood flow (or fluid transfer) to the moving part. In all cases where it has evolved, the scale was small enough that the fluid issue wasn't a problem.

Stephen J. Gould wrote a good essay on it from what I remember.

At the macro scale?

No. I think Gould gave 2-3 examples, including the flagellum. He gives a clear account of the many things standing in the way of wheels evolving on the macro scale.

It's about 7 years since I read it though, so I don't remember the details.

[cowiz]

Interesting question.
I can't think of a circumstance where it could evolve through natural selection, since it hasn't already.

It has several times. The main constrain is blood flow (or fluid transfer) to the moving part. In all cases where it has evolved, the scale was small enough that the fluid issue wasn't a problem.

Stephen J. Gould wrote a good essay on it from what I remember.

At the macro scale?

No. I think Gould gave 2-3 examples, including the flagellum. He gives a clear account of the many things standing in the way of wheels evolving on the macro scale.

It's about 7 years since I read it though, so I don't remember the details.

I mentioned the fucking flagellum but no one took me seriously. Do I have a credibility issue?

[Pappa]

I dunno why everyone ignored you pawiz.

[cowiz]

I dunno why everyone ignored you pawiz.