14: Human Variation - An Adaptive Significance Approach

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Leslie E. Fitzpatrick
Society for Anthropology in Community Colleges

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Learning Objectives

Distinguish between adaptations and adjustments as ways of coping with environmental stressors.
Provide examples of adjustments humans use to cope with thermal stressors.
Describe how specific patterns of human adaptations and adjustments are correlated to natural selection processes.
Summarize the role of solar radiation in variations of human skin tone, and explain why reduced pigmentation is advantageous in northern latitudes.
Compare and contrast the various genetic mutations present in Tibetan and Ethiopian populations that allow them to survive at high altitudes.
Define the relationship between specific genetic mutations in some human populations and certain infectious diseases, such as the sickle-cell trait mutation and malarial infection.

As early humans left Africa and spread across the globe, they faced numerous challenges related to their new environments. Beyond genetically influenced changes in physiology as a result of evolution, humans have developed lifestyle strategies to cope with and even thrive in a wide range of habitats. The ways populations of humans met such challenges, coupled with their geographic separation throughout the majority of the last two hundred thousand years, have led to the many forms of adaptation in our species. This chapter focuses on the complexities of modern human variation through the lens of human evolutionary history.

Thumbnail: These animals are representative of Allen’s rule. Credit: Allen’s Rule (Figure 14.16b) original to Explorations: An Open Invitation to Biological Anthropology by Mary Nelson is under a CC BY-NC 4.0 License.

This chapter is a revision from “ Chapter 14: Human Variation: An Adaptive Significance Approach ” by Leslie E. Fitzpatrick. In Explorations: An Open Invitation to Biological Anthropology, first edition , edited by Beth Shook, Katie Nelson, Kelsie Aguilera, and Lara Braff, which is licensed under CC BY-NC 4.0 .