The pattern of evolution demonstrated in the scenario between the Rough-skinned newt and garter snakes is **co-evolution**.
1. **Co-evolution**: This occurs when two or more species reciprocally affect each other's evolution. In this case, the newt has evolved to produce a potent neurotoxin as a defense mechanism, while the garter snakes have developed resistance to this toxin through genetic mutations to continue preying on the newts.
2. **Example**: As the newts increase their toxin levels to deter predators like the garter snakes, the snakes, in turn, evolve mechanisms to resist the toxin, leading to an ongoing evolutionary arms race between the two species.
This continuous cycle of adaptation and counter-adaptation is a hallmark of co-evolution, highlighting how the interactions between species can drive their evolutionary paths in response to each other's traits and behaviors.
