Fisherian runaway: Difference between revisions

== Mechanism ==

[[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 over many generations, in which the one sex (either male or female) becomes more choosy about a heritable trait for the simple reason that it will make the offspring more attractive. As the the choosiness for the trait increases, the selective pressure to prefer the trait increases too, forming a [https://en.wikipedia.org/wiki/Positive_feedback_loop positive feedback loop]. In response to the increased choosiness, the other sex evolves to enlarge, overcomplicate or beautify that trait in efforts of becoming more attractive. The exponential nature of positive feedback loops exerts a strong selection pressure that can, in theory, even overcome the selective pressure for survival itself and hence lead to extinction. For example, exaggerated traits may reduce mobility and increase vulnerability to predators and to sudden environmental changes.