Evolution And History

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CHAPTER 13

Human Adaptation

to a Changing World

Chapter Preview

What Is Evolutionary Medicine?

Evolutionary medicine, a branch of medical anthropology, uses the principles of evolutionary

theory to contribute to human health. Basic to this approach is framing health issues in terms

of the relationship between biological change and cultural change. Biological evolution shaped

humans slowly over millions of years while cultural change occurs relatively quickly. The resulting

dissociation between human biology and current cultural practices may lead to disease. Also,

because culture shapes even scientific interpretations of the human body, evolutionary medicine

acknowledges that some physiological phenomena regarded as symptoms of disease can also be

understood as naturally evolving defense mechanisms.

How Have Humans Adapted

Biologically to Naturally Occurring

Environmental Stressors?

When faced with an environmental stressor, the human spe-

cies has responded biologically at three distinct levels: genetic,

developmental, and physiological. Some genetic adaptations

are expressed in terms of phenotypic variation of continuous

traits. Even when the genetic bases to these adaptations are

not precisely known, scientists can study them through com-

parative measurement of the associated phenotypic variation.

In addition, the long period of human growth and devel-

opment allows the environment to interact with genes and

shape the human body. Short-term changes or physiological

adaptations occur in response to a particular environmental

stimulus. Today, the rapid rates at which cultural processes

change human environments pose new biological challenges

with important consequences for our species.

How Are Humans Adapting

in the Face of Globalization?

The interconnectedness of humans to one another and

to the environment is critical for understanding human

adaptation and disease. Today, because local human environ-

ments are shaped by global political and economic systems,

these features directly impact the distribution of health and

disease. Simply describing disease in terms of biological

processes, such as those associated with infection or malnu-

trition, leaves out the ultimate reasons that some individuals

are likelier than others to become sick. Examination of the

impact of political processes on disease can reveal its social

causes, bringing us closer to finding long-lasting cures.

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