Reddit mentions of Mathematical Models in Biology (Classics in Applied Mathematics)

Depends entirely on your background.

1. Are you a high school student or freshman college student who's thinking of an academic career in this area? If yes, then pick the regular biology major and take as much math courses as is permitted by your curriculum. It's essential to have the entire calculus sequence, differential equations, and 1-2 calculus-based courses in probability and stats before seriously tackling math biology. A couple of game theory courses from economics will also help. Then, in any typical American university you should be able to find specialized advanced courses in evolutionary biology and complex systems - typically from the biology department but occasionally from math, comp-sci, econ and sociology departments. They may be undergrad or grad-level, but you would be well qualified for them regardless.
   
2. Are you a 3th/4th year college student? Chances are it's too hard to formally switch into the field of evolutionary biology at this point, but there will still be self-contained topical courses of interest offered at the above-mentioned departments, and you'll have to figure out on a case-by-case basis if you'll be allowed to take them and then further develop your interest by yourself.
   
3. Are you out of college and trying to study this subject as an amateur? Depending on the extent of your math background, these self-contained books might be suitable for you:
   
   (from the math side of modeling)
   
   https://www.amazon.com/Mathematical-Biology-Classics-Applied-Mathematics/dp/0898715547/
   
   (from the application side of modeling)
   
   https://www.amazon.com/Cooperative-Species-Human-Reciprocity-Evolution-ebook/dp/B0050PADW0/
   
   https://www.amazon.com/Complex-Adaptive-Systems-Introduction-Computational-ebook/dp/B00CTLFPNK/
   
   Note that these recommendations are tailored for someone specifically interested in the "modelling" side of evolutionary dynamics. All three books above are written by active academics with a strong background in math.
   
   For someone who's rather interested in the broad subject of evolutionary biology as a whole, the answer would be very different, but I'm not qualified to answer that question because, as mentioned, I have virtually no knowledge of the empirical/scientific side.

I've been fairly happy with Edelstein-Keshet's Mathematical Models in Biology, which (if memory serves) derives a lot of the equations so you can see for yourself what kind of thinking is going on. I'd definitely get it from your local library for a quick gander.