From the frozen tundra of the northern Arctic to the arid deserts of sub-Saharan Africa: humans not only survive, but thrive in some of the most extreme and remote environments on the planet. This is a testimony to the remarkable adaptive capacity possessed by our species. Each habitat places different stressors on human populations and they must adapt to mitigate them. That is, adaptation is the process by which humans and other organisms become better adapted to their environments. These adaptations include not only physical changes such as the increased lung capacities seen in high-altitude natives, but also cultural and behavioral adjustments such as traditional Inuit clothing styles, which retain heat very effectively but discourage the deadly sweat that induces hyperthermia in climates arctic. Indeed, it appears that this later adaptive mechanism is often far more responsible for allowing humans to populate such a wide variety of habitats, spanning all seven continents, than biological mechanisms. Of course, not all adaptations are entirely beneficial, and in fact can be maladaptive, particularly behavioral adaptations and highly specialized physical adaptations in times of environmental change. Because people rely heavily on social learning, maladaptive behaviors such as sedentarization and overeating – both of which contribute to obesity – are easily transmitted from person to person and culture to culture, as seen in the adoption by part of the Inuit of American cultural elements. The relationship between man and his environment has long been the subject of academic debate. Many scholars, from Greco-Roman times to the late 18th century, believed that one's environment was predominantly dete...... middle of paper...... increases the body's surface area for optimal cooling, and the ASIAN FOLD EYE possessed by Asian and Inuit populations of Mongolian origin effectively helps protect the eyes from freezing winds and strongly reflected solar radiation found in arctic climates. This last example demonstrates the other side of evolutionary adaptations: that they are gradually lost as they are acquired, and could in fact become maladaptive if the climate warms or people migrate to warmer environments. The next type of adaptation is also genetic, but it does not involve changing the genes themselves, but rather the way they are expressed. Because humans possess a significant amount of “genetic plasticity,” developmental adjustments can occur by turning particular genes on or off to adapt to current environmental conditions at birth and during adolescence..