Evolution and Medicine: Practicing medicine with only half of biology?

August 5, 2009

evolutionMark Schwartz MD

Why do we age? Why is congestive heart failure so common? Why do so many of us wear glasses? Why is there a menopause? Why must we sleep? Why do we get febrile when infected?

Medical students, trainees, and physicians are drawn to questions of how the body works, so your likely first response to these intriguing questions is to think about pathophysiologic answers. These proximal, mechanistic explanations form the conceptual and cognitive framework for our learning, practice, and research in medicine.

However, such bodily mechanisms tell only half of the story. To fully understand the complexities of these problems, we must ask evolutionary questions as well. Based on the work of Tinbergen and Mayr, Randolph Nesse developed this Figure describing the four questions that must be answered to provide a full explanation of any biological trait.[1]

 

evolution2The aim of this new Clinical Correlations column is to share fascination with the view of health and illness through an evolutionary lens. Through this lens, the very nature of questions one can ask shifts from proximate “what” questions about mechanism and development in individuals to evolutionary “why” questions about selection forces and phylogenetic development.

 

Medicine is based on biology, and biology is based on evolution, but medical education and research rarely taps into the elegance and power of evolutionary principles. In fact, in a 2003 survey of North American medical school deans, 48% said evolution is important for physicians. However, not a single medical school teaches evolutionary biology as basic science, no medical school requires evolution as a prerequisite for admission, only 16% had PhD faculty in evolutionary biology, and schools devoted a median of 4 hours of curricular time on core topics in evolution.[2]

 

Medical Schools are complex institutions and slow to change. Jack Colwill, Professor at University of Missouri, aptly wrote, “We educate tomorrow’s physicians in today’s system while maintaining yesterday’s beliefs.”[3] Curricular time is precious and many valuable fields vie for larger roles in educating physicians. However, Dr. Nesse, Professor of Psychiatry at University of Michigan, argued, “Teaching evolution as a basic science does not add extra facts, it adds a framework on which those facts can be organized and it can make medical education more coherent. It can give students a real feel for the organism…”[4]

 

In this new series, we hope to explore humanity’s traits and vulnerabilities by asking evolutionary questions. Along the way, we hope to address some core evolutionary concepts and stimulate your interest in learning more about this core basic science. The next column will explore the mystery of aging from an evolutionary perspective.

 

For a list of web sites, conferences, videos, and books on the interface of medicine and evolution see the attached recommended reading.

Dr. Schwartz is an Associate Professor in the NYU Division of General Internal Medicine.

1. Nesse RM. Tinbergen’s Four Questions Organized, http://nesse.us, 2000.
2. Nesse RM, Schifman JD. Evolutionary Biology in the Medical School Curriculum. BioScience 2003;53:585-587.
3. Colwell J. Primary Care Medicine and the Education of Generalist Physicians. In GeneralistMedicine and the U.S. Health System. Isaacs SL and Knickman JR, Editors. Jossey-Bass, San Francisco, CA 2004.
4. Nesse RM. Evolution: Medicine’s most basic science. Lancet 2008;372:S21-27.

5 Responses to Evolution and Medicine: Practicing medicine with only half of biology?

  1. Mark Joy on August 6, 2009 at 9:48 am

    Great idea! I look forward to it.

  2. robert maslansky on August 7, 2009 at 7:30 pm

    As a recently retired faculty member from my job as the medical director of the out-patient clinics in the Division of Alcoholism & Substance Abuse I have spent some profitable time at my laptop. Curiously, it is never on my lap. But that, of course, is beside the point.

    The POINT is that I thoroughly enjoyed what appears to be a new entry in the race to steel away some of my time, the blogs under the rubric, “Clinical Correlations”. It is beautifully conceived, masterly realized and thoroughly enjoyable. Please keep those cards and letters acomin’

    Robert Maslansky MD Clinical Professor of Medicine, Depts of Medicine & Psychiatry

  3. [...] discussed in the previous column in this series [1], biological questions of causality like these are of two types. In medicine we typically ask [...]

  4. [...] As discussed in the previous column in this series [1], biological questions of causality like these are of two types. In medicine we typically ask proximate “how” questions about mechanisms (pathophysiology) or development (ontogeny) over an individual’s lifetime. We less commonly ask evolutionary “why” questions about function (adaptation) or development of a trait in species over millennia (phylogeny). [...]

  5. Fever: Friend or Foe? | Clinical Correlations on November 20, 2013 at 12:11 pm

    [...] Evolutionary principles can be helpful to explain to the patient that fever may actually be beneficial, that it could be a sign that the body is working to heal itself. Given the high metabolic cost of fever, it is unlikely that it would have evolved and been conserved so widely among animals if it did not have adaptive value, i.e., if it did not contribute to reproductive fitness. This is a good illustration of the value of considering evolutionary explanations, along with proximate explanations, in understanding disease (see this blog’s previous discussion o…).[4] [...]

Leave a Reply

Your email address will not be published. Required fields are marked *

*