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Logical thought

  1. Jan 13, 2005 #1

    DaveC426913

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    Why did nature never invent the wheel?
     
  2. jcsd
  3. Jan 13, 2005 #2
    Hooking up nerves, blood vessels, etc. to a spinning disk is very difficult, as they would tend to twist and break. If the disk were dead matter, then the question of how to grow it and actuate it is difficult. Finally, the benefit is not so great, because natural ground is usually bumpy and legs are more suited to that.
     
  4. Jan 13, 2005 #3
    Bacteria such as E. coli swim through liquid using a rotating 'propellor'. So nature has invented a rotary motor, if not quite a wheel.
     
  5. Jan 13, 2005 #4
    because God told her not to.
     
  6. Jan 14, 2005 #5
    i thought man invented wheel??

    OR, do you mean to say, that wheel was already existed on earth before apes evolved into humans.
     
  7. Jan 14, 2005 #6

    Gokul43201

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    He means to ask : "If the wheel is such an efficient means of transport, why is it that no form of animal life has evolved with wheel-like appendages ?"
     
  8. Jan 14, 2005 #7

    Curious3141

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    Well, Nature has exploited circular objects and surfaces in many of its designs. Many mammalian joints follow the classic ball-and-socket design that allows circumduction (full 360 degree range of movement).

    More explicitly, on a microscopic level, the movement of ova down the Fallopian tubes is nothing if not wheel-like. Ditto for the rolling motion of leucocytes along the vascular wall prior to integrin/selectin mediated interactions leading to diapedesis in the process of acute inflammation.

    Macroscopically : tumbleweed (Russian thistle) uses the principle of a wheel (or rather a ball) in dispersion.
     
  9. Jan 14, 2005 #8
    Last edited: Jan 14, 2005
  10. Jan 14, 2005 #9

    DaveC426913

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    Bart got the right answer. The wheel requires an axle - a physically separate component. How does a living body create a component that it can't nourish?

    Ceptimus figured out that it is a trick question. Bacteria have indeed invented the wheel (or at least the propellor).


    The trick is that on a bacterial scale, the square-cube* law is not so restrictive. You can transfer nourishment across the boundary between the two components.

    *The square-cube law: a doubling of an organism along one dimension creates an area through any component of the organism that is four times, and a mass/volume of eight times.

    It limits the sizes of living creatures in many ways,
    - one of which is where nutrients to feed a volume of tissue are, by geometry, forced to pass through a surface defined by an area. Common examples are: the lungs, the placenta,
    - another of which is supporting bones (a femur on a 12 foot man is 4x the area, but a 12 foot man weighs 8x as much.)

    The law works in reverse: smaller creatures have more surface per unit volume.
     
  11. Jan 15, 2005 #10
    Maybe just a little larger than Bacteria is one half of the first of us all.
    Sperm also moves by rotating its tail.
     
  12. Jan 15, 2005 #11

    DaveC426913

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    I believe that sperm do not use an axle mechanism. I believe that sperm send a circular pulse down the shaft for their tail, which does not require actual rotation.

    You can simulate this by holding a towel or whip or string, and rotating your hand as if you were drawing a circle on a blackboard with a piece of chalk.
     
  13. Jan 16, 2005 #12

    matthyaouw

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    You know, an armadillo on an incline can act in a wheel like manner if given a little shove in the appropriate direction. :biggrin:
     
  14. Jan 16, 2005 #13
    Matt
    The armadillo (and hedgehog) is creating a ball not a wheel.

    Dave
    I'm sure the text I'd read discribed it as rotation, and I'm sure they would describe medical items acuratly.
    However in thier circles they may not see a differance between "rotation" and "circular flexing".

    With control of the DNA - combining maybe Shellfish for a hard 'wheel' and Crab for exoskelaton and molting do you think you could design a "living wheel that might work for the adult. Power from some other limb so only nourishment need go through the axial and maybe not all the time.

    It'd be wierd for sure.
     
  15. Jan 17, 2005 #14
    Probably legs where more likely to develop, considering the chemistry and physics of spontaneous mutations to the first replicating chemicals.

    However, there does exist some wheel-like motion in the animals kingdom:
    http://www.blueboard.com/mantis/bio/wheel.htm
     
    Last edited: Jan 17, 2005
  16. Jan 17, 2005 #15
    Nice link - Wheel like is the key I'm sure. Using the entire body is more like making a section of a ball though. I'm sure Dave refers to a wheel with axle to connect to the body.

    To evolve something (or force it if you could control the DNA) would maybe start with something like a smooth solid oblong ball, requiring no nourishment at all, enclosed in a 'socket' much like the ball in the mouse or trac-ball used with our PC's.
     
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