Grade 9 Ecology Practice Exam

Coevolution happens when two species push each other to adapt through their interactions. In a predator–prey arms race, the prey evolves traits that help it escape—like greater speed or agile maneuvers—while the predator evolves traits that improve its ability to catch prey—such as faster sprinting or stealth. This back-and-forth creates a cycle of reciprocal adaptations in both species, which is the essence of coevolution. The gazelle and cheetah example fits best because each species’ evolution is directly driven by the other. The other scenarios don’t show this reciprocal evolution. A plant growing in shade due to light, regardless of pollinators, is an adaptation to an abiotic factor, not a back-and-forth with another species. A herbivore feeding on a non-native plant with no adaptations reflects little to no reciprocal evolution. Evolution occurring only in plants misses the partner in the interaction, so it isn’t coevolution.