[thaumasiotes]

> An interesting theory as to why we never evolved with wheels is the idea that an evolutionary improvement requires a viable intermediate state

Not really; wheels aren't an improvement in the first place so there is no need to explain why they didn't develop. Note that it's easy to make robots that use wheels, and difficult to make robots that use legs, but we make legged robots anyway so that they'll be able to handle environments other than dedicated roads.

(More recently, we make flying robots, sidestepping the issue that we don't really know how to do legs well.)

[darksaints]

Okay, but evolution has given us some pretty expansive diversity in traits across the biological world. No single trait is pareto optimal, but relatively superior/inferior depending on context. Wheels have some pretty extreme efficiency advantages, useful for both speed as well as endurance. They come with disadvantages too, but there are plenty of animals who never need to leave environments where legs are optimal or even necessary for survival. There are some animals that will never leave grassy plains, for example. Yet none of them have evolved wheels either. We don't have marine animals that have evolved propellers, despite an edge in efficiency.

[XorNot]

Evolution is content with a very long iteration cycle and a very high failure rate.

Human engineering is much more efficient - building things we understand, we accomplish in decades what takes nature millions of years or is straight up not viable.

[codetrotter]

I sometimes think about evolution and its relation to human engineering, and I don’t know if it is a useful thought but, evolution created humans, and therefore, human creation is also in fact a product of evolution in nature itself.

In that way, evolution evolved itself by creating humans, and through us evolution is now happening at an accelerated rate in some aspects.

I try not to get all philosophical, because I know that other people, who are actual philosophers, have thought about these things already and I can’t compete with them but I can’t help but think about such things anyway.

[modo_mario]

Have you considered how these elements essentially detached from the body (it's why they'd be able to spin around) would grow and the like?

[drewbug]

"Many bacteria are equipped with a flagellum, a helical propeller that allows bacteria to travel."