Darwin's theory of evolution is explicitly competitive, yet co-operation between individuals is a common phenomenon. The Prisoner's Dilemma model is central to the teaching of the evolution of co-operation. The best-known explorations of the Prisoner's Dilemma are the tournaments run by Robert Axelrod in the 1980s. Aimed at students of biological…

This exercise demonstrates the principle of parsimony in constructing cladograms. Although it is designed using mammalian cranial characters, the activity could be adapted for characters from any group of organisms. Students score categorical traits on skulls and record the data in a spreadsheet. Using the Mesquite software package, students…