Fisherian runaway: Difference between revisions

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===Animals===
===Animals===
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>
Some animal species have been theorized to have gone extinct partly due to runaway selection. A prominent example is the Irish elk.  Female Irish elk may have selected male elk with increasingly larger antlers.  Some recovered antlers measure 9 ft (2.7 m) across and weigh over 90 pounds (40 kg). The extreme nutritious cost to grow such huge antlers, coupled with the burden of such a heavy load, were possibly 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> Natural selection would have favored males with smaller bodies and antlers for their lower nutritional needs and superior mobility, however the sexual selection pressures were strong and the ornament has become so fixed in a positive feedback loop, that it may have ultimately caused extinction.<ref name="moen1999" />
Certain species have been theorized to have gone extinct partly due to runaway female sexual selection. A prominent example is the Irish elk.  Female Irish elk selected male elk with larger bodies as well as increasingly larger antlers.  Some recovered antlers measure 9 ft (2.7 m) across and weigh over 90 pounds (40 kg). 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> Natural selection would have favored males with smaller bodies and antlers for their lower nutritional needs and superior mobility, however the sexual selection pressures were strong and the ornament has become so fixed in a positive feedback loop, that it ultimately caused extinction.<ref name="moen1999" />
 
Theoretic models suggest extinction can only occur in combination with sudden environmental changes rather than by runaway selection alone, that is, 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><ref>https://biology.stackexchange.com/questions/239/is-there-any-evidence-that-sexual-selection-may-lead-to-extinction-of-species</ref>


===Humans===
===Humans===
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