Naked Science Forum
General Science => General Science => Topic started by: _Stefan_ on 19/05/2007 13:05:32
-
Are there wheels in nature? Or are humans the first to invent/develop them?
-
How do you define a wheel?
There are ball and socket joints which are capable of rotation, but are prohibited from continues rotation by the attached muscles.
There are things in the natural world that do continuously rotate.
The big invention for humans was not really the wheel, but the axle (i.e. a way of harnessing a continuously rotating object to a stationary object - although nature does use axles for components that can rotate in a non-continuos manner).
-
There are some lizards that bite their tail and roll down-hill when threatened. They are in a sort of circle so they may be considered a wheel. Any other examples, people?
-
Are there wheels in nature? Or are humans the first to invent/develop them?
What about Saturn's rings?
-
Nature could not "invent" the wheel because of the severe problems of ensuring a blood and nervous supply to a rotating object that can perform an undefined number of turns in the same direction the best you can get are ball and socket joints like hips and eyeballs.
-
If you look at the structure of the ATPase,(mitochondria and chloroplasts) it is a rotating wheel on a "shaft", that rotates in 1 direction for a long time... [;D]
-
There are some lizards that bite their tail and roll down-hill when threatened.
They are in a sort of circle so they may be considered a wheel.
Any other examples, people?
What about Tumbleweed ?
-
What about pangolins, armadillos, and milipedes? Can't they roll?
-
What about beating tail (flagellum) of sperm?
Doesn't the flagellum rotate, relative to the head of the sperm?
The flagellum doesn't need a blood supply or nerve connections...
-
What about beating tail (flagellum) of sperm?
Doesn't the flagellum rotate, relative to the head of the sperm?
The flagellum doesn't need a blood supply or nerve connections...
In my mind that's more like a propellor...
-
What about beating tail (flagellum) of sperm?
Doesn't the flagellum rotate, relative to the head of the sperm?
The flagellum doesn't need a blood supply or nerve connections...
In my mind that's more like a propellor...
True, but it needs a bearing, and a bearing is a lot like a wheel in terms of how to connect stuff across it.
Incidentally, a wheel isn't much use unless you also have a road. This may explain why nature hasn't bothered with many wheels.
-
Worth looking up bacterial flagella. Apparently some really do rotate, driven by what looks like a biological synchronous motor!
-
a wheel isn't much use unless you also have a road
That is true for moving large objects on a 2D surface in 1g gravity.
But in a neutral-buoyancy environment (eg water, ISS), there is no net force, so you don't need a road.
- For small objects (eg aerosols), they move very effectively in 3D, not limited to 2D, so they don't need a road either.
[a flagellum] needs a bearing
I agree. The cylindrical structure which couples the flagellum to the head of the sperm acts as a combined axle and motor, with embedded mitochondria.
The centriole at the end of the flagellum appears to be the bearing that transmits the propulsive force to the rest of the sperm.
I agree that the net result is a propeller.
See: https://en.wikipedia.org/wiki/Sperm
https://en.wikipedia.org/wiki/Centriole#Fertility
-
But in a neutral-buoyancy environment (eg water, ISS), there is no net force, so you don't need a road.
- For small objects (eg aerosols), they move very effectively in 3D, not limited to 2D, so they don't need a road either.
Things with actual wheels (rather than propellers) need a road of some sort.
-
You might consider whether the rotating cylinder rudder is acting as a wheel or a propellor.
-
Nature does look at utilizing models that increase efficiency. Wheels (balls) are good a transversing resistance so you will find examples of how various fauna and flora utilize them. Take for example the Dung beetle. To allow it to move large masses (dung) across distances, it creates a ball.
Google search video Dung beetle
-
Dung beetle
Good example, although the dung itself is not a living creature.
But what about tumbleweeds and the armadillo...