Rotating locomotion in living systems – the use of wheels and propellers by organisms – has long been pondered among biologists and writers of speculative fiction. Rolling and wheeled creatures have appeared in the legends of many cultures. While other human technologies, like wings and lenses, have common analogues in the natural world, and several species are able to roll, structures that propel by rotating relative to a fixed body are represented only by the corkscrew-like bacterial flagella. Macroscopic organisms have apparently never evolved wheels, and this is attributed to two main factors: limitations of evolutionary and developmental biology, and disadvantages of wheels, when compared with limbs, in many natural environments. Wheels, beyond the molecular scale, may not be within the reach of natural evolution, and may be infeasible to grow and maintain with biological processes. Compared with limbs, they are often less energy- efficient, less versatile, and less capable of traversing or avoiding obstacles. These environment-specific disadvantages of wheels also explain why some historical civilizations abandoned them.
Read more: https://en.wikipedia.org/wiki/Rotating_locomotion_in_living_systems
_______________________________ Today's selected anniversaries:
447:
A powerful earthquake destroyed large portions of the Walls of Constantinople, including 57 towers. https://en.wikipedia.org/wiki/Walls_of_Constantinople
1856:
Scenes of Clerical Life, the first work by English author George Eliot, was submitted for publication. https://en.wikipedia.org/wiki/Scenes_of_Clerical_Life
1935:
The Hawker Hurricane, the aircraft responsible for 60% of the Royal Air Force's air victories in the Battle of Britain, made its first flight. https://en.wikipedia.org/wiki/Hawker_Hurricane
1977:
The Kelly Barnes Dam in Stephens County, Georgia, U.S., collapsed, and the resulting flood killed 39 people and caused $2.8 million in damages. https://en.wikipedia.org/wiki/Kelly_Barnes_Dam
1995:
Madagascar's Rova of Antananarivo, which served as the royal palace from the 17th to 19th centuries, was destroyed by fire. https://en.wikipedia.org/wiki/Rova_of_Antananarivo
_____________________________ Wiktionary's word of the day:
Bolshevism: 1. The strategy used by the Bolsheviks in attempting to gain power in Russia. 2. The Communist totalitarian political ideology adopted by the Russian Soviet Federative Socialist Republic and the Union of Soviet Socialist Republics; Marxism-Leninism. https://en.wiktionary.org/wiki/Bolshevism
___________________________ Wikiquote quote of the day:
Where words prevail not, violence prevails; But gold doth more than either of them both. --Thomas Kyd https://en.wikiquote.org/wiki/Thomas_Kyd