The chemical basis for the color change in leaves during autumn is primarily due to the breakdown of chlorophyll. As daylight hours decrease and temperatures cool, chlorophyll production halts, allowing other pigments, such as carotenoids (yellow and orange) and anthocyanins (red), to become more visible. This process contributes to the vibrant colors seen in fall foliage and signals the transition of plants into a state of dormancy, preparing them for winter conditions.