Editing Sexual selection (section)

=== Reproductive success ===

{{Further|Bateman's principle}}

[[File:Irish Elk front.jpg|thumb|The enormous sexually selected antlers of the [[Irish elk]] might have helped it on its way to extinction.<ref name="Gould 1974"/>|alt=Photograph of a museum specimen of an Irish elk skull with large antlers]]

The [[reproductive success]] of an organism is measured by the number of [[offspring]] left behind, and by their quality or probable [[fitness (biology)|fitness]].<ref>{{cite journal |last=Orr |first=H. A. |title=Fitness and its role in evolutionary genetics |journal=Nature Reviews Genetics |volume=10 |issue=8 |pages=531–9 |date=August 2009 |pmid=19546856 |doi=10.1038/nrg2603 |pmc=2753274}}</ref><ref>{{cite book |last=Starr |first=Cecie |title=Biology: The Unity & Diversity of Life |year=2013 |publisher=Cengage Learning |page=281}}</ref><ref name="PHYS-20140129">{{cite news |last=Vogt |first=Yngve |title=Large testicles are linked to infidelity |url=http://phys.org/news/2014-01-large-testicles-linked-infidelity.html |date=January 29, 2014 |work=[[Phys.org]] |access-date=January 31, 2014 |url-status=live |archive-url=https://web.archive.org/web/20140131114327/http://phys.org/news/2014-01-large-testicles-linked-infidelity.html |archive-date=January 31, 2014 }}</ref> Sexual preference creates a tendency towards [[assortative mating]] or [[homogamy (biology)|homogamy]]. The general conditions of sexual discrimination appear to be (1) the acceptance of one mate precludes the effective acceptance of alternative mates, and (2) the rejection of an offer is followed by other offers, either certainly or at such high chance that the risk of non-occurrence is smaller than the chance advantage to be gained by selecting a mate. [[Bateman's principle]] states that the sex which invests the most in producing offspring becomes a limiting resource for which the other sex competes, illustrated by the greater [[parental investment|nutritional investment]] of an egg in a [[zygote]], and the limited capacity of females to reproduce; for example, in humans, a woman can only give birth every ten months, whereas a male can become a father numerous times in the same period.<ref>{{Cite journal |last=Bateman |first=Angus J. |author-link=Angus John Bateman |title=Intra-sexual selection in Drosophila |journal=Heredity |volume=2 |pages=349–368 |year=1948 |doi=10.1038/hdy.1948.21 |pmid=18103134 |issue=Pt. 3 |doi-access=free }}</ref> More recently, researchers have doubted whether Bateman was correct.<ref name="Newcomer">{{Cite journal |last1=Newcomer |first1=Scott D. |last2=Zeh |first2=Jeanne A. |last3=Zeh |first3=David W. |date=31 August 1999 |title=Genetic benefits enhance the reproductive success of polyandrous females |journal=Proceedings of the National Academy of Sciences |volume=96 |issue=18 |pages=10236–10241 |doi=10.1073/pnas.96.18.10236 |pmid=10468592 |pmc=17872 |bibcode=1999PNAS...9610236N |doi-access=free }}</ref>