Editing Reproductive success (section)

{{short description|Passing of genes on to the next generation in a way that they too can pass on those genes}}
[[File:Sperm-egg.jpg|thumb|right|199px|A sperm fertilizing an egg in [[sexual reproduction]] is one stage of reproductive success]]
'''Reproductive success''' is an individual's production of offspring per breeding event or lifetime.<ref name=":03">{{Cite book|date=2010|chapter=Reproductive Success |chapter-url=https://www.sciencedirect.com/science/article/abs/pii/B9780080453378001194 |pages=64–69|doi=10.1016/B978-0-08-045337-8.00119-4|title=Encyclopedia of Animal Behavior|last1=Moreno|first1=J.|isbn=978-0-08-045337-8}}</ref> This is not limited by the number of offspring produced by one individual, but also the reproductive success of these offspring themselves. 

Reproductive success is different from [[Fitness (biology)|fitness]] in that individual success is not necessarily a determinant for adaptive strength of a [[genotype]] since the effects of chance and the environment have no influence on those specific genes.<ref name=":03" /> Reproductive success turns into a part of fitness when the offspring are actually recruited into the breeding population. If offspring quantity is not correlated with quality this holds up, but if not then reproductive success must be adjusted by traits that predict juvenile survival in order to be measured effectively.<ref name=":03" /> 

Quality and quantity is about finding the right balance between reproduction and maintenance. The [[disposable soma theory of aging]] tells us that a longer lifespan will come at the cost of reproduction and thus longevity is not always correlated with high fecundity.<ref name="pmid593350">{{cite journal | vauthors = Kirkwood TB | title = Evolution of ageing | journal = Nature | volume = 270 | issue = 5635 | pages = 301–4 | date = November 1977 | pmid = 593350 | doi = 10.1038/270301a0 | bibcode = 1977Natur.270..301K | s2cid = 492012 }}</ref><ref>{{Cite journal |last1=Pierotti |first1=Raymond |last2=Clutton-Brock|first2=T. H.| name-list-style = vanc |date=August 1989 |title=Reproductive Success: Studies of Individual Variation in Contrasting Breeding Systems |journal=The Condor |volume=91 |issue=3 |pages=750 |doi=10.2307/1368138 |jstor=1368138 |hdl=1808/18030 |hdl-access=free }}</ref> 

[[Parental investment]] is a key factor in reproductive success since taking better care to offspring is what often will give them a fitness advantage later in life.<ref>{{Cite book|last=Williams|first=Tony D. | name-list-style = vanc |date=2017 |title= Physiological Adaptations for Breeding in Birds|publisher=Princeton University Press|doi=10.23943/princeton/9780691139821.003.0006|isbn=978-0-691-13982-1 |chapter=6. Parental Care: Incubation and Chick-Rearing |pages=198–246 |jstor=j.ctt7rrg2.11 |chapter-url=https://www.jstor.org/stable/j.ctt7rrg2.11 |oclc=794491917 }}</ref> This includes [[mate choice]] and [[sexual selection]] as an important factor in reproductive success, which is another reason why reproductive success is different from fitness as individual choices and outcomes are more important than genetic differences.<ref>{{cite journal | vauthors = Fisher RA | title = The evolution of sexual preference | journal = The Eugenics Review | volume = 7 | issue = 3 | pages = 184–92 | date = October 1915 | pmid = 21259607 | pmc = 2987134 }}</ref> As reproductive success is measured over generations, [[longitudinal study|longitudinal studies]] are the preferred study type as they follow a population or an individual over a longer period of time in order to monitor the progression of the individual(s). These long term studies are preferable since they negate the effects of the variation in a single year or breeding season.