Practice question

Predator–prey coevolution involves reciprocal genetic change: adaptation in one species alters selection acting on the other. Improved prey escape traits, such as faster acceleration, vigilance, armor, toxins, or better camouflage, can reduce capture success. Predators may then be favored to evolve greater speed, enhanced sensory systems, detoxification, cooperative hunting, or altered tactics. This reciprocal escalation or counteradaptation is often called an evolutionary arms race, although trade-offs and ecological context can prevent indefinite improvement. Prey change alone demonstrates adaptation to predation; it becomes evidence of coevolution when predator populations subsequently evolve in response and the relevant traits are heritable. Predator extinction ends reciprocal interaction, constant prey growth ignores predation, and unchanged predator behavior provides no counterresponse. Coevolution can also be diffuse when several predator and prey species shape selection. Rigorous evidence compares traits and fitness across populations, uses common-garden or genomic approaches, and shows reciprocal selection rather than assuming it from correlated phenotypes. Better escape is therefore the clearest first step toward a coevolutionary dynamic.