Let me begin this post by defining some terms that some of you might not be familiar with. First is the term “Atavism.” In biology an atavism is an evolutionary throwback. What this means is that traits sometimes reappear in some people or some species that had disappeared generations ago. For example, a newborn human infant covered in somewhat thick hair would be considered an atavism as such an infant would be deemed an “evolutionary throwback” and might look like something akin to, say, Homo habilis.
Second is the term “Vestigial” which can be defined as small remnant of something that once was much larger or maybe even more noticeable. In biology, it is defined as an organ or body part that degenerates or which has become rudimentary or even atrophied and which has become basically functionless in the course of evolution. For example, the appendix in humans is usually considered a “vestigial organ.” or structure. A vestigial structure has lost its original ancestral function. It can refer to either structures (organs) or attributes that have lost some or all of their ancestral function in a species. However, these structures or attributes have been retained during the course of evolution for whatever reason.
That said let’s talk about wisdom teeth in humans!
Wisdom teeth in modern humans are considered to be “vestigial structures.” That is, they aided our ancient human ancestors in grinding plant foods in such species as Australopithecus or H. habilis but they are really no longer needed in modern humans, Homo sapiens. In terms of dentition it’s believed that earlier species of ancient humans had larger jaws with more teeth than we have today. Many of our ancient ancestors were dependent on tough plant foods so they needed a large chewing, crushing apparatus like more teeth and larger jaws.
However, with the advent of agriculture about 10 kya (thousand years ago) soft diets became the norm for our species. It’s postulated that the result of these soft diets with the advent of farming resulted in our jaws growing in such a way as they were less protruding than our ancestors and one result of this was there was no room for our wisdom teeth. If this theory is true, and I believe it is, then it is NOT an evolutionary change. Rather, this is an ENVIRONMENTAL CHANGE! Thus, it is HIGHLY important that we realize that our environment DOES have an impact on our bodies sometimes more and sometimes less. In the case of wisdom teeth it appears our environment had a rather HUGE impact on our ancestors. It is because of this change in our teeth and jaw brought about by soft diets, and by extension farming, that our wisdom teeth today are basically useless. The changes in jaw size or protrusion and the fact that wisdom teeth remain is due to environmental not evolutionary changes and that is why our wisdom teeth have not disappeared along with our heavy brow ridges! But wait! Some modern humans don’t have wisdom teeth!!……………..
That’s right! You read that right! SOME people alive today do not have wisdom teeth! In fact, wisdom teeth differ by population. For example, Tasmanian Aborigines have NO wisdom teeth and almost 100% of indigenous Mexicans all have wisdom teeth according to statistics. And the difference seems to be related to the PAX9 gene and other genes.
Formally, our wisdom teeth are known as “third molars.” They are commonly called “wisdom teeth” because they appear later than our other teeth typically around ages 17 to 25. Presumably we are wiser at these ages than we are in childhood which, of course, is debatable.
So there you have it. Now you know all about wisdom teeth and thanks to our ancient human ancestors they cause many of us BIG problems today. And now you know who to blame! 🙂