Given that the formula I had derrived for the fitness change in natural selection was so clean, I was under no delusion that I had been the first to discover it. I was hoping at some time to find out who had discovered it first, but this is a bit of a difficult task when it comes to mathematical formulas. It’s easy to do a search on some things, but formulas are not so easy. Happily, it didn’t take me long to notice a reference to Fisher’s fundamental theorem in the chapter listing of his book on After a bit of fishing, I found the relevant information at WikiPedia (and other places), so I’ve decided to write a little post about it now.

Those who are perceptive may have noticed the correspondence between our equation for natural selection and Fisher’s fundamental theorem of natural selection. Fisher defines his theorem in the following manner:

“The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time.” – R.A. Fisher, “The Genetical Theory of Natural Selection”)

This can be rewritten as:

w’ = w + StVar