You can study whatever you want, I am questioning if you can be considered "expert" if you profoundly fail at the topic of your field.
In the end, those are 2 different domains. Knowing a certain theory and overcoming all the limitations of applying those are very different.
Let me give you another example: Formula 1 or MotoGP. The engineers are not driving the thing, and the drivers are not engineering it. Claiming that one needs to be able to be a master in the other is weird.
You are confusing the person with the field of study.
This confusion is more obvious if you think about the superconductor/ expert on superconduction example.
A superconductor is a material which conducts direct current with near zero resistance. You can test if something is a superconductor by aligator clipping a voltage source on it and measuring the resistance.
An expert on superconductors is a person who is knowledgeable about the phenomenon of superconduction. You can test if someone is such an expert by asking them questions about what materials are superconducting, under what circumstances they are, what phenomena can be observed during super conducting and etc etc.
If you get confused and clip the aligator clips on the expert you will measure a larger than zero resistance. If you start asking quiz questions from a superconductive material about superconductivity you will observe that it does not answer any of them.
These two things are fundamentally different. You can be good at one while miserably failing the other, or vice versa.
Similarly someone who studies evolutionary biology is someone who studies the effect of evolution on different kind of living things. They are good at predicting things which they can prove later either experimentally, or with observations about creatures and their circumstances. It has nothing to do with the act of procreation. A disembodied AI can be an expert at evolutionary biology as long as it has good theories on the topic which it can support with relevant evidence.
Through two practical examples. Someone who is good at surviving at evolutionary timescales is for example a person with a handfull of healthy, and fit children. Each of them carrying a mutation which makes their female offspring (daughters, grand-daughters and so on) have a tiny bit wider hips thus increasing their chances of having uncomplicated births, thus increasing the chances of having lots of lots of offspring a tiny bit.
Someone who is good at studying evolutionary biology for example might be able to explain why animals trapped on an island all over the world seem to change in a way that their offspring becomes smaller in stature.
Mixing up these two is as silly as measuring the resistance of your superconductivity experts.
"I have a doctorate, and equally important, 3 kids - that's how you know I am a real expert".