ABSTRACT
From our humble beginnings in the African tropics during the Pleistocene, Homo sapiens has spread to all of the world’s continents and today successfully colonizes a range of habitats and environments that is unprecedented among living mammals. From the Saharan desert to the rain forests of the Congo and the Amazon, from the highlands of the Himalayas and the Andes to the frozen Arctic, humans have proved to be among the most adaptable creatures on our planet. While we obviously owe much of this success to cultural variation and technological expertise, anthropologists are very interested in understanding how human biology contributes to our amazing ability to live and even to prosper in extreme habitats across the globe. Anthropologists are also keen to understand the ways in which life in different habitats has led to some of the morphological and physiological differences we see in human populations. These differences include such traits as the color of our skin, hair, and eyes; the size and shape of our bodies and limbs; the size of our lungs and hearts and the efficiency of our cardiovascular systems; and our ability to stay warm when it is cold and to cool down when it is hot. Morphological differences between people in different populations are known as polytypic differences, and they comprise the raw material that forms the basis of all racial classifications. From our evolutionary perspective, we seek to determine whether these traits contribute to the survival and reproduction of their bearers in the habitats in which they are found. In other words, we seek to understand the adaptive significance of the polytypic variations in human morphology that underlie racial classifications.
