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Fisherian runaway: Difference between revisions
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Base sexual preference of an entire species can make them more likely to go extinct.<ref>https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2656.12601</ref><ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691875/</ref><ref>https://www.sciencedaily.com/releases/2018/04/180411131646.htm</ref><ref>https://www.nature.com/articles/d41586-018-04059-7</ref> But the runaway selection of the most exaggerated members alone, arguably cannot cause the entire species to go extinct. However, together with environmental factors, runaway female selection has played a role in extinction, for example in the the Irish Elk.<ref>The evolution of sexual strategy in modern humans: an interdisciplinary approach by Collins, Kendra Marie, https://studyres.com/doc/2550939/--california-state-university</ref><ref>Moen et al., 1999</ref> There are scientific models that show under a stable environment, a feedback loop can develop where male intrasexual competition leads to a linear increase in size dimorphism, outstripping the ability of the environment to to support this increased size.<ref>http://www.jstor.org/stable/2410506</ref>The name Fisherian runaway derives from the originator of the concept, Ronald Fisher, the 20th century British statistician, geneticist, eugenicist and racialist. | Base sexual preference of an entire species can make them more likely to go extinct.<ref>https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2656.12601</ref><ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691875/</ref><ref>https://www.sciencedaily.com/releases/2018/04/180411131646.htm</ref><ref>https://www.nature.com/articles/d41586-018-04059-7</ref> But the runaway selection of the most exaggerated members alone, arguably cannot cause the entire species to go extinct. However, together with environmental factors, runaway female selection has played a role in extinction, for example in the the Irish Elk.<ref>The evolution of sexual strategy in modern humans: an interdisciplinary approach by Collins, Kendra Marie, https://studyres.com/doc/2550939/--california-state-university</ref><ref>Moen et al., 1999</ref> There are scientific models that show under a stable environment, a feedback loop can develop where male intrasexual competition leads to a linear increase in size dimorphism, outstripping the ability of the environment to to support this increased size.<ref>http://www.jstor.org/stable/2410506</ref>The name Fisherian runaway derives from the originator of the concept, Ronald Fisher, the 20th century British statistician, geneticist, eugenicist and racialist. | ||
== Animal examples == | |||
Despite there being debate on the role of sexual selection causing extinction without other factors present, everyone agrees that, combined with environmental factors, sexual selection can and does cause "evolutionary suicide" or extinction due to runaway selection.<ref>https://biology.stackexchange.com/questions/239/is-there-any-evidence-that-sexual-selection-may-lead-to-extinction-of-species</ref> | |||
Theoretic models suggest extinction cannot happen due to sexual selection without sudden environmental changes and as long the ornamented individual bears the cost.<ref>"Sexy to die for? Sexual selection and risk of extinction" by Hanna Kokko and Robert Brooks, Ann. Zool. Fennici 40: 207-219. [[https://www.jstor.org/stable/23736526 Abstract]]</ref> | |||
===Irish Elk=== | |||
Certain species have been theorized to go extinct partly due to runaway female sexual selection. The Irish elk’s extinction was at least in part, due to runaway sexual selection. Female Irish elk selected male elk with larger bodies as well as increasingly larger antlers. Some recovered antlers measure nine feet across and weigh over 90 pounds. The extreme nutritious cost to grow such huge antlers, coupled with the burden of such a heavy load, were more than the males could handle, particularly as their food source density decreased during environmental changes.<ref>The evolution of sexual strategy in modern humans: an interdisciplinary approach by Collins, Kendra Marie, https://studyres.com/doc/2550939/--california-state-university</ref> In this case, natural selection would have favored males with smaller bodies and antlers needing fewer nutritional resources, however the sexual selection pressures were so strong, and had become so fixed in a positive feedback loop, that it ultimately cost the loss of the entire species.<ref>Moen et al., 1999</ref> | |||
<gallery mode="packed" widths="400" heights="200"> | |||
File:1920px-Male Peafowl (Peacock) at China National GeneBank, Shenzhen.jpg|A male Peafowl with completely useless plumage | |||
File:Skull of Sabre-Toothed Tiger - Museum of Anthropology - La Paz - Baja California Sur - Mexico (23835305595).jpg|Skull of the Sabre-Toothed Tiger | |||
File:Irish Elk Side.jpg|Skeleton of the Irish Elk | |||
</gallery> | |||
== Mechanism == | == Mechanism == | ||
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Also called the ''good genes hypothesis'', this claims the exaggerated ornament is a costly and hence a reliable signal of other desirable traits. For example, a peacock with a very large tail would be easy prey (which is costly), and thus would most likely have other good traits that make up for this handicap (good genes). There is, however, little supporting scientific evidence. In humans in particular, beauty is not strongly correlated with health at all (those it is weakly), and even less with cognitive ability.<ref>https://incels.wiki/w/Scientific_Blackpill#Attractive_people_are_perceived_much_more_positively_than_they_really_are</ref> | Also called the ''good genes hypothesis'', this claims the exaggerated ornament is a costly and hence a reliable signal of other desirable traits. For example, a peacock with a very large tail would be easy prey (which is costly), and thus would most likely have other good traits that make up for this handicap (good genes). There is, however, little supporting scientific evidence. In humans in particular, beauty is not strongly correlated with health at all (those it is weakly), and even less with cognitive ability.<ref>https://incels.wiki/w/Scientific_Blackpill#Attractive_people_are_perceived_much_more_positively_than_they_really_are</ref> | ||
== Humans == | == Humans == | ||