antagonistic coevolution

Antagonistic coevolution is a process where two species evolve in response to each other, often leading to an "evolutionary arms race". This occurs when the interaction between species enhances their antagonism, meaning they develop increasingly sophisticated methods of attack and defense.123

For example, in predator-prey relationships, faster prey may drive the evolution of faster predators, and vice versa. Similarly, the thick shells of some mollusks and the powerful claws of their crab predators are believed to have coevolved through this escalating cycle of defense and counter-defense. This reciprocal evolution is a key factor in organizing biological communities and can even lead to the formation of new species.132