Just-a-ponderin; not trying to reconvene the evolution v creation dialectic.

I wonder why (other than the flagellum bacteria) there is not a life form that uses rotary motion.

Why hasn't nature made more use of rotation? Rolling is a more efficient way of moving over smoothe ground than is walking. Why aren't there critters with wheels?

("Hoop snakes" don't count)

-- Lars (lars@indy.net), September 10, 2001

Answers

Well, I just thought of one, sort of. Those helicopter-like seed pods that are shed by maple trees.

-- Lars (lars@indy.net), September 10, 2001.

Lars,

I love to view the spinning phalaropes nourishing themselves off the skin of the Pacific.

"A shorebird, the phalarope, creates a vortex in order to feed. In shallow water the bird spins rapidly around, pushing with her feet. As she spins, her feet and legs create an upward welling vortex, which pulls small creatures up from the bottom. After she has spun for awhile, she stops and samples her meal."

[Above description shamelessly nicked from the following page]:

http://cgee.hamline.edu/see/crs_and_concept/see_essay_primer_4-5.htm

-- flora (***@__._), September 10, 2001.

Flora--

I see that there really is such an animal as a phalarope. At first I thought you were putting me on, much as my dad would do when he told of "hillside gophers" (gophers with forelegs and hind legs that were shorter on one side so that they could move around and around hillsides and remain level. These poor creatures came in two varieties---the short left-leggeds (CCW only) and the short right-leggeds (CW only). When they met on a trail, there was a big fight.

-- Lars (lars@indy.net), September 10, 2001.

There are several other rotary dimensions in biology---the ball-and-socket hip joint, the eye ball to cite a couple.

Still, why didn't nature evolve life-forms with wheels? I can imagine at least two reasons. First, there would be no selective advantage to a wheeled creature. Except for the Bonneville salt flats (which contains no food), there is no naturally occurring smoothe surface for a wheeled creature to inhabit. Second, it may not be possible to successfully evolve wheels in a living creature. This would reguire sealed bearings, wheel surfaces (bone?, horn?) that do not wear out quickly, etc.

Yet, considering the many extraordinary abilities that living creatures have evolved (flying for example), I have to believe that wheels could have evolved if wheels would have provided an advantage, natural selection-wise, to some creature.

The only life-form that I know of (beside the flagellum) that uses wheels and other rotary motion is the human being and the human "created" the wheel out of thin air by means of an idea.

-- Lars (lars@indy.net), September 10, 2001.

The Atom

-- Cherri (jessam6@home.com), September 10, 2001.

Lars,

There are oodles of sea creatures utilizing cylindrical, if not strictly spherical forms.

My first take on the dearth of round terrestrial critters is a probable predation disadvantage. The armadillo & pill bug come to mind, illustrating the need for additional protective adaptations to supplement their cool orbiness.

Whaddya think, huh?.

[Did you really believe I would lead you astray above? I have been known to lead a mean snipe hunt - no foolin'!]

-- flora (***@__._), September 10, 2001.

Lars,

Up your ass with a red-hot rotating railroad rivet.

-- (nemesis@awol.com), September 10, 2001.

I can also think of two reasons why this form didn't evolve.

First, evolution is a scavenger, co-opting existing structures for new purposes. I think if wheels had evolved even once, they'd have been snagged by a wide variety of life forms for a wide variety of purposes. So part of the reason is simple accident.

Second, we usually think of a wheel *and axle*. Yes, some creatures are round, and some creatures roll, but this is their entire body doing it (as with the phalarope or the pill bug). There is no mechanically effective way to get nutrients from the axle to the wheel, and still have the wheel rotate freely.

-- Flint (flintc@mindspring.com), September 10, 2001.

Well the flagellum do it and evolution is so creative surely it could have evolved organic "brushes" over a few billion years. If evolution is only a scavenger then where did so many remarkable original evolved traits come from, ie where were they scavenged from? I have to believe that wheeled creatures did not evolve simply because there was no need, ie they would not have been the "fittest".

-- Lars (lars@indy.net), September 10, 2001.

Lars:

I can't answer your question about original structures until you provide an example. The thing about evolution is, every structure evolved from a different structure. New structures have never appeared by magic.

The flagellum barely works, and only because nutrient transfer from the "axle" to the "wheel" can only happen on microscopic scales. Stephen Jay Gould discussed this at some length in one of his essays. Gould holds that the mechanical problems on larger scales are insurmountable.

As for wheels serving no sufficiently useful purpose, this is pure blue sky speculation. Certainly we have found countless uses for wheels in a boggling number of forms. It's hard to believe nature could not find any, but who could possibly say?

-- Flint (flintc@mindspring.com), September 10, 2001.

Flint--

Actually, I think a tractor tread would be far more successful an adaptation than an evolved roller skate. As they say, time will tell (a billion years or so).

Flora--

Do I think you would lead me astray? Do I think the pope is a Catholic?

"Roundness" I see (don't forget turtles), but rotary motion I don't.

IMO armadilloes have too many peccadilloes.

Cherri--

"The atom", interesting. When I studied physics, they were still diagramming atoms as solar systems. I have not kept up on nuclear matters. Do you know how atoms are portrayed nowadays? Has anyone ever "seen" an atom? I visualize a blob of pulsing light.

-- Lars (lars@indy.net), September 10, 2001.