It used to be that there were few good introductory texts to helps students in evolutionary biology (and human sociobiology) learn about the construction and analysis of mathematical models. Thankfully, there are several now. Each has its strengths and emphasizes different sorts of biological problems.

This is the best book I've found for teaching nervous biologists the techniques of projection matrices and analyzing stability in multi-dimensional systems. It's patient, clear, and biologically motivated (as opposed to mathematically motivated). Nice clear treatment of limit cycles.

My and Rob Boyd's book focuses on sociobiological problems, game theory, and population modeling that involves frequency dependence. We typically show more steps in derivations than the other books. You might say we assume the reader is fairly nervous about calculus.

Nice treatment of stochastic modeling, sustainability and bio-economic analysis. Has a nice chapter on probability that many students will find helpful.

Very approachable and example-motivated presentation. This may be the best first book for the math-phobic biologist. Also says more about solving problems through computer programming (very common among professional theorists) than other texts in the list.

Troy Day has made an informative page about this book.