Among Ronald Fisher’s many contributions to statistics, genetics, and evolutionary theory at large was his “fundamental theorem of natural selection”:
“The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time.”
See:
In plain language (with llm help):
“The rate at which a population becomes better adapted (its average fitness increases) is directly proportional to the amount of genetic variation for fitness it already has.”
In other words:
- If there’s lots of genetic diversity that affects survival and reproduction, natural selection has more “raw material” to work with.
- The more variation in who leaves more offspring, the faster the population improves in fitness (adaptation).
- If there’s no variation, evolution has nothing to act on, so fitness won’t increase through selection.
Great stuff, and limited to a description of a model evolutionary process.
Online, e.g. in e/acc, I am seeing it used as justification for diversity of methods/approaches.
Something like:
diversity fuels progress
I think this has weak justification.
I’d prefer an analogy from portfolio theory.
Something like:
spread the bets
or
variance is the price of adaptability