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[[File:Buff.jpg|thumb|right|One popular sex icon for men: Zyzz, died young of sudden cardiac arrest from too much steroid use to make himself look hyper-masculine]] | [[File:Buff.jpg|thumb|right|One popular sex icon for men: Zyzz, died young of sudden cardiac arrest from too much steroid use to make himself look hyper-masculine]] | ||
'''Fisherian runaway''' is a hypothesized mechanism by which sexual selection can lead to exaggerated and sometimes even maladaptive ornamentation. There is evidence that entire species have become extinct due to runaway sexual selection. The name derives from the originator of the concept, Ronald Fisher, the 20th century British statistician, geneticist, eugenicist and racialist. | '''Fisherian runaway''' is a hypothesized mechanism by which sexual selection can lead to exaggerated and sometimes even maladaptive ornamentation and constitutes an important mechanism in the evolution of [[beauty]]. There is evidence that entire species have become extinct due to runaway sexual selection. The name derives from the originator of the concept, Ronald Fisher, the 20th century British statistician, geneticist, eugenicist and racialist. | ||
==Mechanism== | ==Mechanism== | ||
[[File:Peacock courting peahen.jpg|alt=|thumb|"The females may be dull looking, but they're very picky." | [[File:Peacock courting peahen.jpg|alt=|thumb|"The females may be dull looking, but they're very picky." A peacock courting a peahen]] | ||
Fisherian runaway is a feedback loop occurring across many generations, in which the one sex becomes more choosy about a heritable trait for the simple reason that others find the trait attractive. Members of this sex are not necessarily consciously aware of other's preferences, rather mutations that lead to preferring traits preferred by others are favored by selection due to the offspring more likely exhibiting traits that are preferred by others. In response to the greater choosiness, the other sex enlarges, overcomplicates or beautifies that trait in efforts of becoming more attractive. The exponential nature of feedback loops exerts a strong selection pressure that can even overcome the selective pressure for survival itself and hence lead to extinction. Such feedback loops can be initiated by arbitrary aesthetic selection, but also when a trait has a similar appearance to attractive or otherwise valuable objects or body parts. For example, women's breasts may have evolved to mimic their buttocks because the latter was already a sexually attractive body part before humans developed upright posture, and then Fisherian runaway may have lead to breasts becoming increasingly larger and rounder. | Fisherian runaway is a feedback loop occurring across many generations, in which the one sex becomes more choosy about a heritable trait for the simple reason that others find the trait attractive. Members of this sex are not necessarily consciously aware of other's preferences, rather mutations that lead to preferring traits preferred by others are favored by selection due to the offspring more likely exhibiting traits that are preferred by others. In response to the greater choosiness, the other sex enlarges, overcomplicates or beautifies that trait in efforts of becoming more attractive. The exponential nature of feedback loops exerts a strong selection pressure that can even overcome the selective pressure for survival itself and hence lead to extinction. Such feedback loops can be initiated by arbitrary aesthetic selection, but also when a trait has a similar appearance to attractive or otherwise valuable objects or body parts. For example, women's breasts may have evolved to mimic their buttocks because the latter was already a sexually attractive body part before humans developed upright posture, and then Fisherian runaway may have lead to breasts becoming increasingly larger and rounder. | ||