Electron cryotomography scan of a Treponema primitia flagellar motor (Image: Gavin Murphy / Nature / SPL)
Wheels are a pretty effective method of getting around. Is there any reason why they never evolved in nature?
• 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”…
