What is the mathematical theory at the heart of evolutionary biology?
You tell me. You're the one who thinks "laying eyes" on prime numbers is akin to observing a 4.5 billion year old earth.
I'm not an expert on it, but I think it is referred to as the neo-Dawninian synthesis and was developed in the early 1900's. Fisher and Haldane are names that come to mind. It's a mathematics of inheritance, variation and natural selection on populations.