I highly recommend 'Self Organization in Biological Systems' by Camazine et. al.

Each chapter describes a single mechanism found in biology: e.g., ant foraging, termite nest building, etc. For each such mechanism they first provide an accessible, well-written description of the process from a biological perspective, and then go on to simulate it using numerical analysis and computer simulation.

http://www.amazon.com/Self-Organization-Biological-Systems-P...

A great book on all of this stuff, if anyone is interested: http://www.amazon.co.uk/Self-Organization-Biological-Systems...