To Lose A Tooth

NCSE's latest outreach activity examines the evolution of human teeth.

To lose a tooth activity cards

Teeth are an important indicator of the health and habits of a person. From the enamel stains of a coffee lover to dental fillings from cavities, we can glimpse into aspects of someone's lived experience. As the hardest tissue within the human body, our teeth often outlast our own lifespan and their hardiness has made them more likely to be preserved in the fossil record of our human ancestors. As a result, teeth are an extremely valuable material for studying the evolutionary history of modern humans, and through analyzing the fossilized teeth of our ancestors we can get a sense of what kinds of food they ate, how their teeth developed, and the prevalence of dental disease in their populations.

The adult human mouth has 32 teeth including incisors, canines, premolars, and molars. Our third molars, also called "wisdom" teeth, not only are our last set of teeth to erupt but are also very susceptible to impaction, a disorder where the tooth does not fully erupt from the gum. Impacted third molars have health implications such as infection and gum disease, yet the surgical removal of wisdom teeth has its own dangers and complications. Interestingly, the problem of third-molar impaction is a modern one. In fact, third-molar impaction is ten times more common in people who eat an Industrial Age diet compared to a diet consistent with foraging.

To Lose a Tooth is an evolutionary board game in which participants explore how natural selection, sexual selection, gene flow, and isolation result in genetic diversity within populations.

So why has third-molar impaction become a problem for modern humans? As mentioned before, diet plays a substantial role in the prevalence of third-molar impaction today. It is theorized that our softer, modern diets (along with the emergence of tool use) has resulted in a reduction of human jaw size. Consequently, our jaws can no longer accommodate all our molars, leading to third-molar impaction as they are the last teeth to erupt. Third-molar impaction is an interesting case study of how technological advances interact with adaptation; though the advent of agriculture and other subsistence strategies allowed us to increase our population size, it was not without consequences on our evolutionary fitness and anatomy.

Focusing on the evolution of human teeth, the Breaking Down Barriers team has created its newest science outreach activity, To Lose a Tooth. To Lose a Tooth is an evolutionary board game in which participants explore how natural selection, sexual selection, gene flow, and isolation result in genetic diversity within populations. Using wooden jaw pieces and teeth of various sizes, participants aim to keep their population alive as food production technologies change and events such as migration, tooth impaction, and conflict come into play. While doing research during the development of this activity, some interesting questions came up for me regarding the relationship between human technological advancement and our evolution: How has human choice transformed the course of our evolution? To what extent has technology altered the impact of evolutionary forces?

It's my hope that this activity also raises thought-provoking questions for its participants, allowing them to interact with evolutionary theory in a fun and engaging way. Human evolution is a topic that can be fraught with tension and conflict, so focusing on a process that we all undergo — the experience of losing a tooth — can help create the common ground needed to make outreach participants comfortable and open to learning.

NCSE intern Anna Ginther
Short Bio

Anna Ginther is a volunteer with NCSE.

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