Teeth: The Great Evolutionary Debate

Greetings everyone and welcome to the Shadow’s Lair. In this episode of “Koraki’s Vlog” I will discuss where teeth come from. First let me introduce myself to those who might be new to the channel. I am Koraki, a fantasy author, disability advocate and geology enthusiast. Today I am going to talk about teeth.

You probably have teeth, or had them at some point in your life, but have you ever wondered how teeth evolved? There are two main hypotheses I will discuss on the evolution of teeth. Before that though I want to touch on another favourite subject of mine- etymology.

The Etymology of the word tooth comes from the old English tōth. This is from the Proto-Germanic tanthu. This from the Proto-Indo-European dent which (I must clarify according to Wikipedia) means “that which eats.” (While I am not keen to cite it as a source, I found this tidbit in the wiki on teeth interesting.) (2,4, and 5)

There are two theories to the evolution of teeth. The “outside in” and the “inside out” theory. In simple terms, they describe how teeth evolved in concurrence with our skin and jaw. The outside in states that teeth evolved from our skin as outer denticles (dermal armor). The inside out theory states teeth evolved from the endoderm (internal skin) of the throat (as pharyngeal teeth) in jawless fish. (1.3.)

There is a third hypothesis which I am not as familiar with. This theory states that the neural crest gene regulatory network and ectomesenchyme are important to tooth generation regardless of the endo-ectoderm (inside or out) theories. I deduced this to mean that teeth didn’t evolve as either or the other, but from both mechanisms. (1.5.)

I was inspired to write this because a friend of mine referred to teeth as mouth bones and this is inaccurate. No matter the hypothesis on how teeth evolved the only conclusion on what teeth are (in my opinion) is: They are hardened mouth skin. Anyway, I hope you found this interesting. As always, there will be links to my sources in a document linked below. Thank you for watching and please don’t forget to like and subscribe.

Citations and Resources Used

  1. Jheon, A. H., Seidel, K., Biehs, B., & Klein, O. D. (2013). From molecules to mastication: the development and evolution of teeth. Wiley interdisciplinary reviews. Developmental biology2(2), 165–182. https://doi.org/10.1002/wdev.63
  2. Merriam-Webster. (n.d.). Tooth. In Merriam-Webster.com dictionary. Retrieved January 31, 2023, from https://www.merriam-webster.com/dictionary/tooth
  3.  McCollum, M., & Sharpe, P. T. (2001, April 6). Evolution and development of teeth. Journal of anatomy. Retrieved January 31, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1594990/
  4. Online Etymology Dictionary. (2019, March 12). Tooth (n.). Etymology. Retrieved January 23, 2023, from https://www.etymonline.com/word/tooth#etymonline_v_15372
  5. Wikimedia Foundation. (2023, January 30). Tooth. Wikipedia. Retrieved January 31, 2023, from https://en.wikipedia.org/wiki/Tooth#:~:text=Teeth%20are%20assumed%20to%20have,inside%E2%80%93out%22%20theory).    

Grand Canyon Karst Seminar

By Damien Knight

Ben Tobin gave this seminar over the karst regions of the Grand Canyon. I arrived late to the seminar, but it was very interesting. When I entered Ben was talking about the morphology of the caves. They are following the fractures into the canyons itself. They mapped the caves from faults and fractures traced in the groundwater. To do that, they had to do dye traces of the different cave entrances.

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Mammoth Cave Connections Seminar Summary

By Damien Knight

On October 19th Chuck Decroix gave a seminar on Mammoth Caves history. His talk summarized the cave history and the connections with WKU. First, he discussed the new visitor center dedicated in 2012. In 2012 Mammoth Cave was 400 miles long. Today Mammoth Cave is 412 miles and is the longest cave in the world.

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Industrial Regulatory Term Asbestos and Minerals It Involves

By Damien Knight

Asbestos has become a common household name. Its hazards a concern blared across our TVs during lawsuit commercials. We all have heard of it, but what is it? Why was it mined? To understand asbestos, we first must define it. Here we will describe the minerals defined, talk about its use, mining, and health effects.

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New Age of Morphology: Presentation Outline

New Age of Morphology: Presentation

By Damien Knight

Traditional Paleontology Is Changing

A. Traditional Paleontology required digging fossils from their matrix and destroying samples to study them.

B. New techniques in tomography are changing the study of morphology in paleontology.

C. CT Scanners and other techniques are aiding our understanding of fossils in greater detail.

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Freedom over Fate: How the Underground Man is Not Free

By Damien Knight

I shall start with a quote from The Underground man himself. “Ha! Ha! Ha! But after all, if you like, in reality, there is such thing as choice.” (Dostoevsky, p.24), In the readings a major theme was free will and morals. Is the good life a free life or are we controlled by fate? To what limits are these freedoms?

In Fear and Trembling freedom is limited by morals or by faith. For Abraham he is both free and bound. He must, due to duty, serve God even if God orders his son’s death. Still this faith left him free. Free of ethics we become bound by faith. “A tragic hero can become a human being by his own strength, but not the knight of faith. When a person sets out on the tragic hero’s admittedly hard path, there are many who can lend him advice; but he who walks the narrow path of faith no one can advise, no one understands.” (K. p.95) This states how even Abraham who seeks freedom from ethics through the duty of faith is not free from being alone. Freedom is fickle.

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Two Weeks Until the Mojave

by Damien Knight

March 9th I leave for my geology trip to the Mojave Desert. I am responsible for talking to my classmates about folds, faults and strike and dip measurements. I will also make sure to take a lot of photos and post on the blog daily (if I manage internet access) about the trip. My next post will be posted today or tomorrow and will be a summary of what will go in my power point concerning faults and folds. I will also post a quick tutorial on taking strike and dip measurements. As you can see, I was very busy this last month preparing for this trip. See ya’ll soon out in the Mojave!


New Year’s Resolutions: A Tradition

By : Damien Knight

Before I list my New Year’s resolutions for this year, I want to give you this post. Another one of my holiday histories.

New Year’s resolutions are nearly as old as New Year itself. It dates back to almost 4000 years back to the kingdom of Babylon. Babylonian New Year was celebrated during the feast time Akitu. It was during Akitu new kings would be crowned or oaths to old kings were sworn. They also would swear oaths to their gods. These oaths often included promises to pay debts.

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