FRAGMENT FROM NATURE for the next two weekends is on coevolution. All creatures have predators; but predation is on a spectrum of relationships that is very wide, including parasitism and symbiosis. It is probably fairer to say that all creatures have other creatures with which they interact to greater or lesser degrees. Being eaten by a lion is rather different than having athlete’s foot. But the common feature within this spectrum is how these interacting creatures coevolve.