This story is meant to be a small and easy introduction to the very basic requirements of evolution: variation, heritability, and selection. Evolution is often perceived as something complicated, but it can be boiled down to a few processes. Evolution simply describes how the genetic composition of populations changes over time. The Hopfs are basically a pretty normal animal population with some differences between the individuals that are transmitted from parents to children. Sometimes the environment influences who is able to survive and reproduce and this brings about a change in the distribution of their genes (or in case of the Hopfs the information in their Hepps). Of course, the Hopfs are not real animals, but the basic principles are the same as in real nature. I am grateful to Katrina Lythgoe for copyediting the English version of the Hopfs.