What is a predator-prey arms race and how can it drive adaptation?

• A. A cycle of successive adaptations and counter-adaptations between predator and prey; leads to improved stealth, speed, or defenses.
• B. A cycle of successive adaptations and counter-adaptations between predator and prey; leads to improved stealth, speed, or defenses.
• C. A cycle of single changes with no long-term effects on either party.
• D. Predators only evolve while prey remain static.

Answer: (B)

Predator-prey arms races are back-and-forth evolutionary contests where each side’s improvements trigger countermeasures in the other. This cycle of successive adaptations and counter-adaptations pushes both predators and prey to develop traits that gain an advantage—like greater stealth, faster speed, or tougher defenses. When prey evolves better camouflage or speed, predators respond with sharper senses, quicker pursuit, or more effective tactics. That in turn pressures prey to refine defenses even further, and the cycle continues. The result is ongoing evolutionary change driven by the reciprocal pressure between the two groups, not a single, one-time adjustment. Descriptions that imply a one-off change or that the prey remains static miss this continuous, reciprocal nature.