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Wisdom Teeth and Stem Cells
Although it seems that wisdom teeth serve no purpose to modern day Homo sapiens, they could actually be the root of a new scientific revolution. Lately, there has been a lot of interest in stem cells because they can act as blank slates and help cure diseases or simply grow into which ever cells are needed. In 2006 scientists revealed that the cells in wisdom teeth can be used as stem cells and even kept frozen for later use in life. Since stem cells are a controversial topic due to the ways they need to obtain them this would be a great finding for the medical community. Considering almost every present day Homo sapiens get their wisdom teeth removed in their lifetime, they each have access to stem cells if they ever need them. This means that if a person contracts cancer or something happens to an organ they could have a supply of stem cells to their disposal. Though, third molars used to aid the ancestors of Homo sapiens as a necessity in terms of every day survival, they now have the power to aid modern day Homo sapiens in a different way. The stem cells can be another way to attempt and fight off an otherwise terminal disease or illness. Though they did not originally evolve for this purpose and had a different underlying advantage they can actually be very beneficial to their present day host. Even though wisdom teeth are no longer a necessity to the survival of Homo sapiens they have not been selected against. One reason that they may not be readily selected against is because modern Homo sapiens’ access to removal eliminates the selective pressures that are acting on the wisdom teeth.

Begin Final Draft
Homo sapiens and their early ancestors have been around for at least a million years (Howells, 1942). Over the course of time evolution has taken its toll on this species. The Homo sapiens of today have diverged from their earliest ancestors in many ways. One difference between the two is vestigial structures (ie. wisdom teeth). Vestigial structures provide evidence for the evolutionary distinctions between Homo sapiens and their predecessors. The Merriam-Webster Dictionary defines vestigial structures as, “a bodily part or organ that is small and degenerate or imperfectly developed in comparison to one more fully developed in an earlier stage of the individual, in a past generation, or in closely related forms.” This essentially means that these structures once proved to be useful and potentially advantageous for the host. However, they no longer play a crucial role and are not needed to aid in the survival of a species. These structures also help portray the many differences between Homo sapiens and to their first ancestors. Although there are several anatomical, behavioral, sensory, and molecular vestigial structures in Homo sapiens, this paper will only explore the original reason for wisdom teeth and why it has not yet been selected against in the population as a whole. The third molars are the last teeth to emerge from the jaw in Homo sapiens. They are often referred to as “wisdom teeth” because they do not normally develop until one’s late teens or early twenties. Anthropologists such as Frank Baker believe that the early ancestors of Homo sapiens evolved a third set of molars to aid in the breakdown of food (Baker, 1890). These groups lived in a time where thoroughly cooking food was not popular or accessible. Therefore, in order to accommodate a diet that was composed of mainly grains and hard food, an extra set of teeth were advantageous in helping to break down their meals. As decades passed Homo sapiens were finding new ways to adapt their diet and prepare food in order for them to consume food that were not as demanding on the jaw. One worldwide change that aided this was in the nineteenth century industrialization emerged, and with that a thriving food processing industry. Food was undergoing a process which made it a lot softer before it was made readily available for people. This led to a change in the selective forces acting on the jaw of humans. Instead of having to bite down very hard and chew aggressively to breakdown food, humans were able to relieve some of that pressure with softer foods. This was one major reason why the jaw size of humans decreased. Since they were not forced to consume such tough foods evolutionary forces started actively selecting upon the size of their jaws (Smail, 2014). The jaws of Homo sapiens changed drastically. Human’s jaws became a lot smaller. However, they still had third molars which would begin to develop when they hit their teenage years (Smail, 2014). When the third molars would develop they would not have enough room to puncture the gums behind the second set of molars. This led to the molars growing in sideways and therefore hitting the second set of molars at their roots and causing the third molars to become impacted in the jaw. If the molars were given the opportunity to continue to grow in sideways, they could potentially cause damage to the rest of the teeth in the mouth and put the host in serious pain. To prevent excessive damage, extractions were necessary to remove the teeth (Smail, 2014). This is when the removal of wisdom teeth started and became popular. Before food became softer it was advantageous for the ancestors of Homo sapiens to develop wisdom teeth. At the time, their jaw was large enough to accommodate them and they did provide many advantages. Teeth in general can be seen as one of the first evolutionary advancements to put Homo sapiens on top of the food chain (Weller, 1628). Teeth were successfully used as a weapon, a defense mechanism, a way to survive, and also a way to attract mates (Weller, 1968). As time passed and all of the animals began to develop teeth one thing was exclusive to vertebrates (Weller, 1968). Human teeth are composed of four distinct types of tissue: pulp, dentin, enamel, and cementum (Weller, 1968). These tissues made teeth nearly as hard as bone which was advantageous because it was a lot more difficult to break them. When the third molars began to develop in Homo sapiens it was a beneficial evolutionary change. Considering Homo sapiens had the means and were able to break down tough grains with the help of their strongest teeth, their molars, they were no longer in a big competition for food. Not being in a competition for food was valuable because they were able to consume more, building up strength. Subsequently, this allowed the ancestors to be reproductively superior, due to the fact that they were able to chew their food better yielding a higher survival rate (Weller, 1968). This would have led to them having a higher fitness compared to others during their time. Another reason a third set of molars were valuable to human’s earliest ancestors was that they did not have proper ways to take care of their teeth (Stevens, 1882). They did not have fluorine treatments, bi-annual trips to the dentist for teeth cleanings, or even toothbrushes and toothpaste for everyday cleaning. The lack of resources resulted in tooth loss much more easily. Once they lost their teeth they had no way to survive because they were unable to chew their food. If they developed another set of molars fifteen years after they were born, even if they had previously lost some of their teeth they were still able to breakdown their food (Stevens, 1882). Present day Homo sapiens have better means for taking care of their teeth. They do not lose them as often, making the extra set of molars unnecessary increasing selection against them. Although it seems that wisdom teeth serve no purpose to modern day Homo sapiens, they could actually be the root of a new scientific revolution. Lately, there has been a lot of interest in stem cells because they can act as blank slates and help cure diseases or simply grow into which ever cells are needed (Dybas, 2007). In 2006 scientists revealed that the cells in wisdom teeth can be used as stem cells and even kept frozen for later use in life (Shere, 2010). Since stem cells are a controversial topic due to the ways they need to obtain them this would be a great finding for the medical community. Considering almost every present day Homo sapiens get their wisdom teeth removed in their lifetime, they each have access to stem cells if they ever need them. This means that if a person contracts cancer or something happens to an organ they could have a supply of stem cells to their disposal. Though, third molars used to aid the ancestors of Homo sapiens as a necessity in terms of every day survival, they now have the power to aid modern day Homo sapiens in a different way. The stem cells can be another way to attempt and fight off an otherwise terminal disease or illness. Though they did not originally evolve for this purpose and had a different underlying advantage they can actually be very beneficial to their present day host. Even though wisdom teeth are no longer a necessity to the survival of Homo sapiens they have not been selected against. One reason that they may not be readily selected against is because modern Homo sapiens’ access to removal eliminates the selective pressures that are acting on the wisdom teeth. Wisdom teeth now seem to pose more of a nuisance. Removal requires a slightly dangerous surgery on the mouth which can lead to infection later on in life or even cause one to be facial paralysis if a nerve is hit (Henry, 1936). One of the key questions about wisdom teeth in present time is why they have not been selected against. Why are Homo sapiens still born with them if most people get them removed? It is thought by Doctor Harrison M. Berry Jr. that in another three or four generations humans may see a large decline in the number of wisdom teeth ("No Wisdom Teeth in Future,” 1951). Today many people are born without wisdom teeth or have less than four. This shows that selection is currently acting on them and researchers may see a rapid decline in wisdom teeth in the near future. However, will it be a positive evolutionary change for humans to be born without them? They do cause a lot of problems; however, with their recent linkage to stem cells and thus helping the host of the cells recover from diseases such as cancer. Would it actually be beneficial for the genes of Homo sapiens to select against wisdom teeth? All in all, yes this vestigial structure is deemed that for a reason nevertheless it may not be so useless after all. The third molar started as an advantageous evolutionary change to aid in the survival of Homo sapiens. Overtime the teeth became bothersome and caused more trouble in removing them than they did in aiding the Homo sapiens at the time. Now they could be a cure-all for many illness and diseases if they are removed and then saved. Overall, wisdom teeth help portray evolutionary selective forces amongst Homo sapiens and their earliest ancestors but they also may lead to the next scientific revolution.

History
I feel as if this article needs to go in depth more on the history of wisdom teeth especially with Homo sapiens. This page does not inform readers on the history of why we have wisdom teeth or how the first humans used them for the breakdown of grain. Secondly, it does not explain why we get them removed today. For example, the jaw of a Homo sapiens is smaller now that it was for our ancestors therefore we do not have adequate amounts of room in our mouth for them. Finally, since they are vestigial structures and evolution is slowly working on them, explain how humans may no longer have third molars in the future due to the disuse of them.

Wisdom teeth may have another function that has been researched in recent years, to be used as stem cells. The stem cells inside of a wisdom tooth recently removed from a patients mouth can be extracted and saved for a later use in brain cells, nerve cells, or to even grow another tooth.

Annotated Bibliography
Samantha Stine 15 September 2014 Evolution 3310 | Thurs 9:10 Annotated Bibliography The Evolution of Wisdom Teeth This article goes into detail about how we are starting to see the evolutionary effects on the human jaw. In recent years, when people get to the age where they need to begin thinking about getting their wisdom removed they go to the dentist and realize they don’t have any. This is a product of evolution. Due to the fact that we no longer need our wisdom teeth some people aren’t developing them.

This article reiterates the idea of the others in terms of why wisdom teeth are so commonly removed these days. However, it goes into more detail regarding how they were successful in allowing humans to reproduce and survive longer. This is why they evolved to have them in the first place. They were at the time advantageous. However, why are they still around even though we no longer use them. Especially since our jaws have transformed to be smaller.

Rachel Cooper explains the approach that anthropologists have on wisdom teeth. Anthropologists think that the reason our ancestors evolved to have wisdom teeth, or our third set of molars, was to accommodate their diet. Their diet included hard food that required extra chewing and strong teeth. This is the reason that we now have wisdom teeth. However, they are now seen as vestigial organs because they no longer serve a purpose. Furthermore, the human jaw has become smaller and therefore when wisdom teeth grow in now they become impacted and can cause numerous problems. Cooper finishes by explaining that it is best for a patient to get their wisdom teeth removed between the ages of 19 to 25 when the roots are 1/3 of the way formed. The reason behind this is it causes fewer problems to the patient and a shorter recovery time. Overall, wisdom teeth seemed as if they were a good idea for our ancestors however they only seem to cause problems for the modern Homo sapiens.

Laura Leslie also talks about our ancestors but gives a different perspective. She illustrates the fact that our ancestors were reproductively superior due to the fact that they were able to chew their food better and thus have a higher fitness compared to others during their time. She also goes into more details about the size of the modern Homo sapiens versus our ancestors jaw. For example over the years our skulls have become smaller while our brain has become larger. To accommodate for this we have a shorter and smaller jaw. Because of this we no longer have the room for the wisdom teeth.

Although it seems that wisdom teeth serve no purpose they could be the root of a new scientific revolution. Lately there has been a lot of interest in stem cells because they can act as blank slates and help cure diseases or simply grow into which ever cells are needed. In 2006 scientists revealed that the cells in wisdom teeth can be used as stem cells and even kept frozen for later use in life. Since stem cells is a controversial topic due to the ways they need to obtain them this would be a great finding for the medical community. Considering almost everyone gets their wisdom teeth out, everyone has access to stem cells if they ever need them.