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It is close to evolutionarily impossible to do a wheel and axle biologically. If the whole animal rolls, sure, but not a full wheel and axle (macroscopically).

It is close to evolutionarily impossible to do a wheel and axle biologically. If the whole animal rolls, sure, but not a full wheel and axle (macroscopically). That is probably the main reason we see zero macroscopic animals with that configuration.

clairity 6y ago
biology on an evolutionary timescale is exceedingly clever, more ingenious than us humans. you don't need an axle, just something roundish (eyeballs or even pearls, for example).
- thombat 6y ago
  The organism will need something like a fluid rotary union so the nervous and circulatory system can reach the rotating part, or that part will be limited to very low metabolic levels (basically diffusion). That will certainly be ingenious.
  - clairity 6y ago
    certainly, but biology is amazing. our muscles are basically chemical ratchets interconnected throughout a mosaic of levers (ignoring the complex control and feedback mechanisms, as well as the energy and waste systems, for a moment). also, your point is why i mentioned pearls--not all tissue needs to be activated or enervated similarly, or at all. we should have no doubt that biology would find a way given enough time.
    - Robotbeat 6y ago
      It has found a way! Through engineering. We invented wheels, and we’re a result of evolution. Dung beetles have engineered something similar, although no axle (yet).
- Robotbeat 6y ago
  And yet it hasn’t happened! So I think that means there are fundamental reasons why it’s difficult for evolutionary processes.
- squarefoot 6y ago
  That would be really really hard to achieve in nature. What about a millipede? To me they're the closest thing to a legged and a tracked-like creature. https://www.youtube.com/watch?v=xysbNbvUDZA https://www.youtube.com/watch?v=xysbNbvUDZA
ggm 6y ago
Not to invoke fiction as proof, but Philip Pullman hypothesized animals with a shiny claw which co-evolves with a tree making wheels. The claw evolves to be the axle and the tree evolves to make the wheels for co-benefit.

clairity 6y ago

biology on an evolutionary timescale is exceedingly clever, more ingenious than us humans. you don't need an axle, just something roundish (eyeballs or even pearls, for example).

thombat 6y ago
The organism will need something like a fluid rotary union so the nervous and circulatory system can reach the rotating part, or that part will be limited to very low metabolic levels (basically diffusion). That will certainly be ingenious.
- clairity 6y ago
  certainly, but biology is amazing. our muscles are basically chemical ratchets interconnected throughout a mosaic of levers (ignoring the complex control and feedback mechanisms, as well as the energy and waste systems, for a moment). also, your point is why i mentioned pearls--not all tissue needs to be activated or enervated similarly, or at all. we should have no doubt that biology would find a way given enough time.
  - Robotbeat 6y ago
    It has found a way! Through engineering. We invented wheels, and we’re a result of evolution. Dung beetles have engineered something similar, although no axle (yet).
Robotbeat 6y ago
And yet it hasn’t happened! So I think that means there are fundamental reasons why it’s difficult for evolutionary processes.
squarefoot 6y ago
That would be really really hard to achieve in nature. What about a millipede? To me they're the closest thing to a legged and a tracked-like creature. https://www.youtube.com/watch?v=xysbNbvUDZA https://www.youtube.com/watch?v=xysbNbvUDZA

ggm 6y ago

Not to invoke fiction as proof, but Philip Pullman hypothesized animals with a shiny claw which co-evolves with a tree making wheels. The claw evolves to be the axle and the tree evolves to make the wheels for co-benefit.