In biology, co-evolution is the mutual evolutionary influence between two species. Each party in a co-evolutionary relationship exerts selective pressures on the other, thereby affecting each others' evolution. Co-evolution includes the evolution of a host species and its parasites, and examples of mutualism evolving through time. Evolution in response to abiotic factors, such as climate change, isn't coevolution (since climate isn't alive and doesn't undergo biological evolution). Evolution in… (More on Coevolution)