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Fisherian runaway: Difference between revisions
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=== Irish Elk === | === Irish Elk === | ||
The Irish elk has been proposed to have gone extinct from female selection giving way to Fisherian runaway. The female Irish elk preferred male Irish elk with large horns. Eventually this preference created a feedback loop that resulted in Irish elk eventually evolving to carry 12 ft (3.6 m) wide horns, which is 3.3 ft (1 m) longer than its height. Energy requirements for Irish elk antler growth were 75% as large as the energy requirements for fat and protein deposition. The enormous amount of calcium required to grow the antlers resulted the calcium being depleted from most of the body causing a state like similar to osteoporosis.<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> | The Irish elk has been proposed to have gone extinct from female selection giving way to Fisherian runaway. The female Irish elk preferred male Irish elk with large horns. Eventually this preference created a feedback loop that resulted in Irish elk eventually evolving to carry 12 ft (3.6 m) wide horns, which is 3.3 ft (1 m) longer than its height. Energy requirements for Irish elk antler growth were 75% as large as the energy requirements for fat and protein deposition. The enormous amount of calcium required to grow the antlers resulted the calcium being depleted from most of the body causing a state like similar to osteoporosis.<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> | ||
=== Guppies === | |||
Biologist John Endler conducted an experiment with Guppies (''Poecilia'') in a tank without predators. The female fish selected males who had strong contrast to the background as they stood out during mate selection. This then made the fish more visible to predators later reintroduced into the same tank.<ref>https://link.springer.com/chapter/10.1007/978-94-015-7682-6_7</ref><ref>http://www.dartmouth.edu/~robertcox/Teaching_files/lecture9.ppt</ref> | |||
This example is not neccessarily related to feedback loops, but clearly demonstrates that sexual selection does not necessarily further and can even ''reduce'' survival. Related to this, one study showed men who have lots of sex were not healthier than others by various metrics.<ref>http://rsos.royalsocietypublishing.org/content/4/1/160603</ref> | |||
<gallery mode="packed" widths="400" heights="200"> | <gallery mode="packed" widths="400" heights="200"> | ||
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File:Irish Elk Side.jpg|Skeleton of the Irish Elk | File:Irish Elk Side.jpg|Skeleton of the Irish Elk | ||
</gallery> | </gallery> | ||
== Humans == | == Humans == | ||