Skeptics often point to human wisdom teeth as an example of a useless human body part. But a new study challenges this evolutionary account.
An impacted wisdom tooth is painful. The agony it causes, however, is not confined to the poor person destined for oral surgery. It also creates discomfort for Christian apologists.
Skeptics often point to human wisdom teeth as an example of a useless human body part. They claim the human body is beleaguered with bad designs (such as the appendix, tonsils, adenoids, the coccyx, body hair), asserting that these structures evince human evolution. Skeptics view these features as vestiges of biological evolution—structures that at one time had use, but lost it as humans descended from evolutionary ancestors.1
When it comes to wisdom teeth many people believe that they serve no useful purpose today. These “third molars” become impacted because of the relatively small size of the human jaw. When the teeth erupt (usually in young adulthood), there is no room for them. In contrast, the Neanderthal jaw was larger and could handle the onset of wisdom teeth. Evolutionary biologists interpret this characteristic to mean that wisdom teeth are leftovers (vestiges) from when humans were another hominid species.2
But a new study challenges this evolutionary account.3 A scientist from the UK studied the size and shape of the human jaw of eleven different people groups around the globe––six were agriculturalists and five engaged in a hunter-gatherer lifestyle.
The food that comprises the diet of these two broad categories varies significantly in consistency. Hunter-gatherers eat food that is raw, requiring longer and more intense bouts of chewing. Agriculturalists eat much softer food.
Research reveals that the jaw shape and size differs, depending on the means of subsistence. People who consume a soft diet (typified by an agriculturalist lifestyle) have shorter, broader jaws. Those who consume a hunter-gatherer diet exhibit longer, narrower jaws. The longer, narrower jaws of hunter-gatherers readily accommodate wisdom teeth. Conversely, wisdom teeth don’t easily fit into the mouths of people with shorter, broader jaws.
This result indicates that, fundamentally, the human jaw is designed to house wisdom teeth. For most of human history people employed a hunter-gatherer lifestyle, and impacted wisdom teeth and associated ailments were likely not present. It was only when humans implemented wide-scale agricultural practices that wisdom teeth caused problems. Still, shorter, broader jaws weren’t inevitably a problem. Without dental care until very recently, people throughout human history lost teeth. This tooth loss would provide room for wisdom teeth. And, of course, having replacement molars was welcome at a time when tooth loss was common.
Such advances take the teeth out of another evolutionary argument while sharpening the case for purposeful design.
1. For a detailed discussion of vestigial structures in the human body and my response to this challenge, see the October 17, 2011 edition of Science News Flash.
2. For example, see “Wisdom Teeth as an Argument for Evolution,” accessed December 9, 2011.
3. Noreen von Cramon-Taubadel, “Global Human Mandibular Variation Reflects Difference in Agricultural and Hunter-Gatherer Subsistence Strategies,” Proceedings of the National Academy of Sciences, USA 108 (2011): 19546–51.