Last to post wins

[Creeperopolis]

Several organisms are capable of rolling locomotion. However, true wheels and propellers—despite their utility in human vehicles—do not seem to play a significant role in the movement of living things (with the exception of certain flagella, which work like corkscrews). Biologists have offered several explanations for the apparent absence of biological wheels, and wheeled creatures have appeared often in speculative fiction.

Given the ubiquity of the wheel in human technology, and the existence of biological analogues of many other technologies (such as wings and lenses), the lack of wheels in the natural world would seem to demand explanation—and the phenomenon is broadly explained by two main factors. First, there are several developmental and evolutionary obstacles to the advent of a wheel by natural selection, addressing the question "Why can't life evolve wheels?" Secondly, wheels are often at a competitive disadvantage when compared with other means of propulsion (such as walking, running, or slithering) in natural environments, addressing the question "If wheels could evolve, why might they be rare nonetheless?" This environment-specific disadvantage also explains why at least one historical civilization abandoned the wheel as a mode of transport.