Which term describes evolution in response to interactions among species?

• A. Coevolution
• B. Gradualism
• C. Punctuated equilibrium
• D. Biotic factors

Answer: (A)

Coevolution is evolution in response to interactions among species. When one species changes, for example a predator becoming better at catching prey or a plant evolving traits to attract specific pollinators, it creates new selective pressures on the other species. Over many generations, those species respond with adjustments of their own, and both lineages shift together. Classic examples include predator and prey relationships in which prey defenses and predator hunting methods escalate, plants and their pollinators evolving together, and hosts and their parasites continuously adapting to each other.

Gradualism describes a slow, steady pace of change over time, not the interaction-based cause of those changes. Punctuated equilibrium suggests long stretches of little change punctuated by brief, rapid shifts, again focusing on tempo rather than the interspecies relationship driving the change. Biotic factors refer to living components in an environment, which can influence evolution but do not define the evolutionary process itself. The term that specifically captures evolution driven by interactions among species is coevolution.