There are 4 Mutation Cards for each trait, 3 of which are neutral or bad, and one which is good. (Nature has usually found a pretty good way of doing things, so mutations are generally not good.) A bad mutation is recorded in various colors, and a good mutation is recorded in red, so the class can see when mutations occur, and how they affect the critter's fit- ness. Mention that mutations are often not percepti- ble (they affect genotype but may not affect pheno- type), so we have used a special coloring scheme to
make it obvious when a mutation has occurred. In the real world, mutations do not occur with a proba- bility of 1 in 6 chances, but if we used realistic proba- bilities, we would not see any mutations during the short course of play.