# Ratio of Beneficial Mutations to Others

**URL:** <https://discourse.peacefulscience.org/t/ratio-of-beneficial-mutations-to-others/6179>\
**Category:** Conversation\
**Tags:** Science\
**Created:** [May 9, 2019, 8:41pm UTC](https://discourse.peacefulscience.org/t/ratio-of-beneficial-mutations-to-others/6179 "2019-05-09T20:41:58Z")\
**Posts on this page:** 1\
**Showing post:** 71

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**Author:** ![Giltil](https://avatars.discourse-cdn.com/v4/letter/g/5f8ce5/32.png) [@Giltil](https://discourse.peacefulscience.org/u/Giltil)\
**Post date:** [May 12, 2019, 7:51am UTC](https://discourse.peacefulscience.org/t/ratio-of-beneficial-mutations-to-others/6179/71 "2019-05-12T07:51:11Z")

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> [@Rumraket](#):
>
> > An exponential decay curve
> 
> Yeah I saw the equation, what I mean is what is the model that predicts that genetic entropy should cause exponential decay in lifespans? It’s not clear why that would be the case even if there really is genetic entropy going on. Why exponential decay in _lifespan_ ? Why exponential?

Genetic Entropy results from the constant accumulation of mutations over generations, like rust in car. This mean that each generation will accumulate the same number of new mutations, which will translate to the same degree of fitness decline at each generation. IOW, fitness will decline at a rate proportional to its current value. Hence the exponential decay curve when you plot fitness against the generations.

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