How can a change in the environment initiate a change in a population?

A change in the environment, such as a shift in climate, availability of resources, or the introduction of new predators, can drive natural selection within a population. Species that possess traits better suited to the new conditions are more likely to survive and reproduce, leading to a gradual shift in the population's genetic makeup. This can result in adaptation to the new environment, speciation, or even population decline if the changes are too drastic for survival. Ultimately, environmental changes act as catalysts for evolutionary processes.