Editing Reproductive success (section)

==Evolutionary trade-offs==
Throughout evolutionary history, often an advantageous trait or gene will continue to increase in frequency within a population only due to a loss or decrease in functionality of another trait. This is known as an evolutionary trade-off, and is related to the concept of [[pleiotropy]], where changes to a single gene have multiple effects. From Oxford Academic, "The resulting 'evolutionary tradeoffs' reflect necessary compromises among the functions of multiple traits".<ref>{{cite journal | vauthors = Ellison PT | title = Evolutionary Tradeoffs | journal = Evolution, Medicine, and Public Health | volume = 2014 | issue = 1 | pages = 93 | date = 2014-01-01 | pmid = 24747118 | pmc = 4204622 | doi = 10.1093/emph/eou015 }}</ref> Due to a variety of limitations like energy availability, resource allocation during [[Developmental biology|biological development]] or growth, or limitations of the genetic makeup itself means that there is a balance between traits. The increase in effectiveness in one trait may lead to a decrease in effectiveness of other traits as result. 

This is important to understand because if certain individuals within a population have a certain trait that raises their reproductive fitness, this trait may have developed at the expense of others. Changes in genetic makeup through natural selection is not necessarily changes that are either just beneficial or deleterious but are changes that may be both. For example, an evolutionary change over time that results in higher reproductive success at younger ages might ultimately result in a decrease in life expectancy for those with that particular trait.<ref>{{cite journal | vauthors = Hayward AD, Nenko I, Lummaa V | title = Early-life reproduction is associated with increased mortality risk but enhanced lifetime fitness in pre-industrial humans | journal = Proceedings. Biological Sciences | volume = 282 | issue = 1804 | pages = 20143053 | date = April 2015 | pmid = 25740893 | pmc = 4375875 | doi = 10.1098/rspb.2014.3053 | s2cid = 13283874 }}</ref>
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