Microevolution Making Macro-changes: a Bite-Sized Analysis

Written by Alexis Bienne Montaller

Illustrated by Ma. Pia Therese Paat

Another win for Tiktok addicts! I was letting time pass by on Tiktok (…as one does) and there was this particular video that caught my eye. Apparently, there are babies now being born without wisdom teeth. Fun fact: I just recently found out I am actually one of those babies. I found it so strange because I always thought it comes around when you get older and that everybody has them. Well, everybody used to but we’ll get to that later.

Third molars or wisdom teeth are teeth that are in the posterior part of the oral cavity. They are the very last set of teeth to erupt into the mouth and often come around young adulthood. This is why they were named ‘wisdom teeth’ because you acquire more wisdom in the late teens and early adulthood. However, with wisdom comes severe pain. As third molars emerge, discomforting pressure is put into the gums and the adjacent teeth, potentially leading to dental decay and difficult cleaning conditions.  

Thus, it’s time to pay a visit to the dentist! Because of the increased likelihood of inflammation or an already-existing infection within the oral cavity, it is common to have them extracted prophylactically or therapeutically as a preventative or treatment measure. 

The loss of wisdom teeth has a pretty big impact on our everyday lifestyle. In order to properly assess its importance, it is necessary to first understand the science of it. 

Genetics Drive Microevolution

Recent generations of humans not possessing the third molars is a good example of microevolution. Microevolution is the adaptive modifications that occur in the frequencies of genetic makeup within a particular species over a relatively short period of time.1 This usually involves changes in the mean value or allele frequency and phenotypes used to describe the passing over of genes. 

Microevolution is supported by Charles Darwin’s theory of natural selection which states that organisms’ traits adapt to their environment in order to increase their chances of survival.2 In essence, microevolution is the adaptation of natural populations to their environment but on a smaller scale and a shorter amount of time. 

Natural selection also acts as a factor in the process of microevolution. There are other factors that also contribute to this phenomenon. Some of these include mutation, migration, and genetic drift.

Mutation3 is characterized as the random changes in the genetic makeup of an organism. This can be caused by the natural consequence of an error in genetic replication during cell division where new copies of a gene are produced. These mutations are then passed on to the next generation which can either be beneficial to the next generation and increase their survival chance or on the contrary, not. It should be noted, however, that by itself, this process cannot explain a significant shift in allele frequency throughout a generation due to the rarity of any given mutation. More often than not, microevolution is a culmination of a sequence of random evolutionary events that lead to a single great event of mutation.

Migration, also known as gene flow, can be defined as the introduction of new alleles from a new population to the gene pool. Migration and microevolution are linked because migration may impact microevolution by bringing new genes into a population or deleting existing ones. It is also theorized that the absence of third molars was caused by migration.4 Humans met diverse climatic circumstances and nutritional patterns when they traveled from one region to another. In other cases, these modifications caused the jaw to shrink, making it more difficult for the third molars to erupt. There are still a lot of studies to be done on this subject but the primary argument that seems to be made in the correlation between mandibles and evolution is the effect of differing environments.

Genetic Drift may be linked to migration as migration can act as a cause for genetic drift. Genetic drift can be defined as the unpredictability that influences the frequency of alleles in a population. This process happens when random occurrences, such as natural catastrophes or migrations, force organisms to leave or die in a population. As a result, the genetic composition of the remaining individuals becomes more prominent in the population, resulting in changes in allele frequencies. 

Hunters to Farms to Foodies: The Modern Human Diet

Considering all of these factors that affect microevolution as a whole, we then apply these concepts to the evolution of molars in humans. There are many factors that may have contributed to this progressive loss. The modern human diet has transitioned from a hunter-gatherer type to a more sedentary agricultural lifestyle since the development of agriculture.5

Before the discovery of fire, our human ancestors had to eat rough, fibrous foods that required a lot of chewing, which resulted in the development of bigger jaws and teeth. Cooking food over fire, on the other hand, softens the texture of difficult meals, making them simpler to chew and digest, and reducing the mechanical strains exerted on the jaw and teeth.6 This resulted in a steady decrease in jaw size and the loss of wisdom teeth over time, which may still be seen in modern humans.

From there, urbanization has moved people towards a more refined and processed diet that is rich in soft foods. This has led to a reduction in the need for more robust teeth, including wisdom teeth. As a result, over time, the human jaw has evolved to become smaller, and the loss of wisdom teeth has become more common. 

Survival of the Toothless

Microevolution is essential for the survival of species. It enables organisms with favorable genetic traits to pass those traits on to their children, resulting in a progressive shift in a population’s gene pool. Microevolution has resulted in a variety of adaptations in humans, one of them being the loss of molar teeth. 

One sure benefit of this is preventing the pain and discomfort associated with infected molars which will also save you money and a painful few weeks. This would also eliminate more possible dental problems in the future. Furthermore, humans are able to consume a wider variety of foods,7 and because of this, It would no longer have a detrimental effect on our ability to get the nutrients we need from our diets. This is because modern humans have already adapted to consuming processed foods that are easier to chew and digest. 

Lastly, the build-up we have been waiting for, this is a good sign that humans are well-adapted to their environment. While wisdom teeth were once important, they may no longer give an evolutionary advantage in the present day. If humans developed without the need for wisdom teeth, it may be viewed as a good adaptation to changing environmental and dietary conditions.8 The notion of an evolutionary advantage offers an intriguing viewpoint on the potential benefits of humans developing to be toothless.

So there you have it! I found it exceptionally fascinating that this evolutionary event is currently taking place at a speed fast enough for it to be noticeable in only just a few generations. We are literally seeing it happen in real-time! 

And yea… I didn’t know that until a Tiktok ago.


Carmody RN, Wrangham RW. 2009. The energetic significance of cooking. Journal of Human Evolution. 57(4):379–391. doi:10.1016/j.jhevol.2009.02.011.

Daegling DJ. 2012. The human mandible and the origins of speech. Journal of Anthropology. 2012. doi:https://doi.org/10.1155/2012/201502.

Dunbar R. 2020. Evolution: What everyone needs to know®. Oxford University Press.

Hawks J, Wang ET, Cochran GM, Harpending HC, Moyzis RK. 2007. Recent acceleration of human adaptive evolution. Proceedings of the National Academy of Sciences. 104(52):20753–20758. doi:10.1073/pnas.0707650104.

Levin S. 2009. The princeton guide to ecology. Princeton University Press. [accessed 2023 Apr 17]. https://www.degruyter.com/document/doi/10.1515/9781400833023/html.

Lieberman D. 2011. The evolution of the human head. Harvard University Press. https://www.hup.harvard.edu/catalog.php?isbn=9780674046368.

Nesse RM, Williams GC. 2012. Why we get sick: The new science of darwinian medicine. Vintage.

Reznick, Ricklefs R. 2009. Darwin’s bridge between microevolution and macroevolution. Nature. 457(7231):837–842. doi:10.1038/nature07894.


Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s