  Biological systems are characterized by the ubiquitous roles of weak, that
is, non-covalent molecular interactions, small, often very small, numbers of
specific molecules per cell, and Brownian motion. These combine to produce
stochastic behaviors at all levels from the molecular and cellular to the
behavioral. That said, students are rarely introduced to the ubiquitous role of
stochastic processes in biological systems, and how they produce unpredictable
behaviors. Here I present the case that they need to be and provide some
suggestions as to how it might be approached.
