What will likely occur if a critical environmental change happens that affects the selective pressures on a species?

When a critical environmental change occurs, it can significantly alter the selective pressures acting on a species. Rapid evolution is a likely outcome because organisms may possess existing genetic variation that allows some individuals to survive and reproduce under the new conditions. This selection of advantageous traits can lead to noticeable changes in the population over relatively short periods.

The process of natural selection plays a critical role in this scenario. Given sufficient genetic variability within a population and the right conditions for reproduction, the traits that enhance survival and reproductive success in the changed environment can become more prevalent in subsequent generations. This can result in adaptations that help the species cope with the new challenges posed by the environmental shift.

The other options suggest outcomes that are less consistent with the principles of evolution and natural selection under changing environmental conditions. For instance, remaining unchanged is unlikely in a dynamic environment, as most species will need to adapt to survive. Extinction without any adaptations overlooks the potential resilience and adaptation capabilities of many species. Lastly, while adaptation can occur slowly, it is more likely to be rapid in response to significant and immediate environmental pressures, provided there is sufficient genetic variation and a favorable reproductive environment.