Editing Reproductive success (section)

==Natural selection and evolution==
To supplement a complete understanding of reproductive success or [[Fitness (biology)|biological fitness]] it is necessary to understand the theory of [[natural selection]]. Darwin's theory of natural selection explains how the change of genetic variation over time within a species allows some individuals to be better suited to their environmental pressures, finding suitable mates, and/or finding food sources than others. Over time those same individuals pass on their genetic makeup onto their offspring and therefore the frequency of this advantageous trait or gene increases within that population. 

The same may be true for the opposite as well. If an individual is born with a genetic makeup that makes them less suited for their environment, they may have less of a chance of surviving and passing on their genes and therefore may see these disadvantageous traits decrease in frequency.<ref>{{cite web|url=https://evolution.berkeley.edu/evolibrary/article/evo_25|title=Natural selection| work =  Understanding Evolution | publisher = University of California Museum of Paleontology |access-date=2018-12-11}}</ref> This is one example of how reproductive success as well as biological fitness is a main component of the theory of Natural Selection and Evolution.