##  [Fisher's Fundamental Theorem of Natural Selection](/fishers-fundamental-theorem-natural-selection) 

  ##  [Fisher's Fundamental Theorem of Natural Selection](https://natural.quantumdictionary.io/fishers-fundamental-theorem-natural-selection-0) 

  

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**Natural & Formal Sciences Dictionary**

 







 

 

 

 



 

 

 

 

Definition

A population‑genetic principle stating that, under a set of idealized assumptions, the instantaneous rate of increase in mean fitness of a population due to natural selection equals the additive genetic variance in fitness.