Human Adaptation

From the frozen tundra of the arctic north to the arid deserts of sub-Saharan Africa – humans not only survive, but even thrive in some of the most extreme and remote environments on the planet. This is a testament to the remarkable capacity for adaptation possessed by our species. Each habitat places different stressors on human populations, and they must adapt in order to mitigate them. That is, adaptation is the process by which man and other organisms become better suited to their environments. These adaptations include not only physical changes like the larger lung capacities observed in high altitude natives but also cultural and behavioral adjustments such as traditional Inuit clothing styles, which very effectively retain heat but discourage deadly hyperthermia-inducing sweat in Arctic climates. Indeed, it seems this later mechanism of adaptation is often much more responsible for allowing humans to populate such a wide variety of habitats, spanning all seven continents, rather than biological mechanisms. Of course, not all adaptations are entirely beneficial, and in fact may be maladaptive, particularly behavior adaptations and highly specialized physical adaptations in periods of environmental change. Because people rely heavily on social learning, maladaptaptive behaviors such as sedentarization and over-eating – both contributing to obesity – are easily transmitted from person to person and culture to culture, as seen in the Inuit’s adoption of American cultural elements.

The nature of this relationship between humans and their environments has long been the subject of academic debate. Many scholars, from the Greco-Roman era until the late eighteenth century, believed one’s environment predominantly dete...

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... increases the surface area of the body for optimal cooling, and the ASIAN EYE FOLD possessed by Asian and Inuit peoples of Mongolian descent effectively helps protect the eyes from the freezing winds and strongly reflected solar radiation found in Arctic climates. This later example demonstrates the other side of evolutionary adaptations – that they are just as gradually lost as they are acquired, and may in fact become maladaptive if the climate warms or the people migrate to warmer environments.

The next type of adaptation is also genetic, but does not involve the changing of the genes themselves, but rather how they are expressed. Because humans possess a remarkable amount of ‘genetic plasticity’, developmental adjustments can occur by turning particular genes on or off to adapt to the current environmental conditions at birth and through adolescence.