It is not true to say that nature hasn’t invented the wheel.
Bacteria have been using it to get around for millions of years. It is the basis of the bacterial flagellum, which looks a bit like a corkscrew and which rotates continuously to drive the organism along.
About half of all known bacteria have at least one flagellum.
Each is attached to a “wheel” embedded in the cell membrane that rotates hundreds of times per second, driven by a tiny electric motor. Electricity is generated by rapidly changing charges in a ring of proteins that is attached to the surrounding membrane.
Positively charged hydrogen ions are pumped out from the cell surface using chemical energy. These then flow back in, completing the circuit and providing the power for the wheel to rotate.
The only nutrients that the flagellum needs are protein building blocks to allow it to grow longer. These are forced up through the hollow center of the flagellum and are assembled into new flagellar material when they reach the end.
It is a very sophisticated piece of nanotechnology and even has a reverse gear that helps the organism find food. So, far from nature not having invented the wheel, given the very large number of bacteria in existence, there are probably more wheels in the world than any other form of locomotion.
There is one form of macroscopic life that rolls like a wheel: tumbleweed. The above-ground part of the plant detaches from the stem and rolls in the wind, dispersing its seeds.
So nature has created a wheel and exploits rotation. Why don’t creatures make more use of them?
Wheels are only effective because we have modified so much of our habitat to accommodate them, though not quite enough, as wheelchair-users will tell us.
Once you move off the roads and paths and try to traverse the rough, wet, muddy, boggy, rocky, sandy, snowy, icy, steep, or fissured terrains that cover most of the world’s land masses, our brilliant invention becomes little better than useless.
Every single part of our body, and those of most other developed organisms, is attached to, or communicates with, the systems that regulate our body, the main ones being the nervous system and the blood system. The same would need to be true of any wheel developed by an organism.
But wheels have to be free to rotate. If they were attached to an organism, they would wrap blood and nerves around the axle.
Wheeled machines such as cars and trains rely on an engine that generates torque.
In the case of wheelbarrows and buggies, leg power is required. Most animal locomotion is produced by muscles which are good at converting chemical energy into work, but can only contract.
To use wheels, nature would need to do one of three things: replace the muscle with a different source of thrust which would be a complex evolutionary process; combine wheels with legs which rather defeats the purpose; or arrive at something improbable such as a bionic bicycle.
Evolution is not a process that “thinks ahead.” It is merely the cumulative effect of natural selection acting on the results of chance mutations. Hence any new forms of life or locomotion only emerge if every single intermediate step conveys some sort of competitive advantage to the organism, or at the very least does not convey any disadvantage.
Therefore wings can evolve because a partial wing conveys some aerodynamic benefit to an animal leaping between tree branches. Similarly a hard shell can evolve because a partial shell conveys at least some protection.
However, it is difficult to think of an intermediate stage to a wheel that would offer any competitive advantage instead of being an unwanted burden.
Of course, in reality wheels have evolved.
Evolution resulted in the emergence of human beings, who have been clever enough to make wheels, and to subsequently alter the environment around them to be suitable for their use.
