Coevolution

Coevolution involves reciprocal evolutionary change in interacting species. This means that as one species evolves (e.g. predator) another species with which it regularly interacts (e.g. prey) also evolves in response, and vice-a-versa. So we might imagine that:

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Cats stalk their prey..mice spend time looking for cats....cats that are better stalkers catch more mice, have more offspring and become more common in the next generation....mice that can see cats further away escape, reproduce , and become more common in the next generation ....cats that are even better stalkers catch more mice, have more offspring and become more common in the next generation....mice that can see cats even further away escape, reproduce , and become more common in the next generation....and so on and so forth.

You can also think of coevolution as a change in the genetic composition of one species (or group) in response to a genetic change in another

What are some other general categories of ceovolutionary relationships besides predator-prey? A good web-based explanation is provided by Prof. David Rand at Brown University. The link is also found on the Out of the Rainforest Study Guide Page.

Organisms affected by other species' toxins may coevolve tolerance or may simply avoid (where possible) the toxic species.