Light's Role in Biological Rhythms: Light has been a crucial factor in the development of circadian rhythms, which regulate sleep patterns and other physiological processes in humans.

Adaptation to Different Light Environments: Human populations have adapted to varying levels of sunlight, influencing skin pigmentation and vitamin D synthesis.

Impact of Artificial Light: The introduction of artificial light has disrupted natural sleep cycles and has been linked to various health issues such as sleep disorders and obesity.

Cultural and Technological Implications: The use of artificial light has enabled cultural and technological advancements by extending productive hours beyond daylight.