How can mathematical modeling help illuminate biological processes? This freshman seminar examines major topics in biology through the lens of mathematics, focusing on the role of models in scientific discovery. Students will learn how to build and analyze models using a variety of mathematical tools. Topics will be organized under three modules: I. Evolution and Behavior (major transitions; evolution of cooperation from bacteria to humans; self-organization and collective behavior; evolutionary game theory); II. Ecology (species interactions; networks; regular patterns); III. Virus Dynamics (spread and contagion; immune system; vaccination).