Paul Andersen explains the concept of coevolution. He begins with an analogy comparing the relationship of humans to technology with those of coevolving species. He then discriminates between coevolution and convergent evolution. He finishes by describing many symbiotic relationships that formed through coevolution. The rough skinned newt and the garter snake, the acacia tree and the acacia ant, and finally all the symbiotic relationships utilized by leaf cutter ants.