Your Inner Fish

Your Inner Fish: A Review of Chapter 4 In Your Inner Fish, a book about the study of evolution in mammals, chapter four is dedicated to the study of teeth. Neil Shubin is explicit in his insistence that teeth are extremely important when studying evolution of the human body. He uses three main points to explain this to the reader. First, through the function of teeth. Then by revealing the anatomy of teeth. And finally by discussing tooth-to-tooth occlusion. Teeth are used to manipulate larger objects so that they may fit into a smaller mouth.

Shubin writes ”Mouths are only so big, and teeth enable creatures to eat things that are bigger than their mouths” (Shubin 60). Without teeth creatures would have a smaller variety of options when it came to food choices. Bigger fish could only eat smaller fish and so on. As explained by Shubin “… teeth can be the great equalizer: smaller fish can munch on bigger fish if they have good teeth” (Shubin 60). So we derive from this that teeth can play an important role in the food chain and thus in evolution. However, teeth play a more important part than this.

By studying theanatomy of teeth many secrets can be revealed about ancient reptiles and mammals. For instance, Shubin relates that “The bumps, pits and ridges on teeth often reflect the diet” (Shubin 60). By knowing the diet of an ancient creature, it is reasonable to see how a paleontologist and evolutionist can follow the emergence of the omnivore over the carnivore and herbivore. And the hardness of teeth make it the “best-preserved animal we find in the fossil record for many time periods” (Shubin 61).

This clue to these ancient animal’s diets can “give us a good window on how different ways of feeding came about” (Shubin 61). So, the shape of the teeth and the general mineral make-up both contribute to the usefulness of teeth to the scientist. Still it remains that the tooth-to tooth occlusion is an imperative discovery when shaping the history of the human body. Reptiles do not have an upper and lower jaw that meet precisely. They rip and tear their food. On the other hand, mammals have an upper and lower jaw that meet in a precise position (Shubin 60-61).

Shubin discusses that in lower rock forms, thus earlier years, fossil records show only reptilian-like mouths that do not have occlusion. As the paleontologist moves up into higher rock formations, he finds more mammalian like tooth formations and smaller jaws. “Go higher in the rocks and we see something utterly different: the appearance of mammalness. The bones of the jaw get smaller and move to the ear. We can see the first evidence of upper and lower teeth coming together in precise ways” (Shubin 62).

From Shubin’s portrayal of the evolution of the mouth and teeth and teeth’s usefulness, it stands to reason that teeth are an important part of the study of ancient mammals and the evolution of the human body. Your Inner Fish:Chapter 4 A Review In his book, Your Inner Fish, Neil Shubin mentions the fact that although the study of teeth are highly important to the study of ancient mammalian history, it is often overlooked or only briefly discussed in anatomy. However, Shubin successfully shows how extremely serious evolutionists and paleontologists take the study of tooth fossils.

In the beginning of chapter 4: Teeth Everywhere, he states that “the tooth gets short shrift in anatomy class: we spend all of five minutes on it” (Shubin 60). But because he fills the chapter with relative stories of paleontologists and himself searching solely for tooth fossils, he reveals that teeth are vital in the study of ancient mammals. Entire expeditions for tooth hunting are explored. Shubin even states that “teeth have a special significance for me, because it is in searching for them that I first learned how to find fossils and how to run a fossil expedition” (Shubin 60).

Thus, implying he had gone on an expedition with the sole purpose of hunting for ancient teeth.. From his references to paleontologists’ search for teeth it seems that teeth are a prominent study in evolution, even if touched on only briefly in anatomy classes. Shubin narrates a story of his first leading expedition where a tiny ancient mammal was discovered in rock and the most significant finding was the revelation of tooth occlusion. He even reports that he was “…being treated like a conquering hero…” (Shubin 70) back on campus following the return from the expedition.

This is a definite sign that the importance of tooth and tooth occlusion are extremely recognized in the world of evolutionary studies. Time, money, and energy are offered to tooth expeditions, and findings are celebrated amongst paleontologists and evolutionists alike. Therefore, it can be concluded from Shubin’s examples that teeth are an important study among scientists who study the history of the human body. Your Inner Fish: A study of Chapter 4 In his book Your Inner Fish, Shubin dedicates an entire chapter to the importance of studying the evolution of teeth when figuring the evolution of the human body.

In order to study ancient teeth and jaws, however, fossil hunting for tooth fossils is imperative. In chapter 4, Shubin reveals just how difficult this expedition for teeth can be. Discovering bones in rock took experience. The work demanded the naked eye notice the signs of bone in rock. This is a difficult feat. According to Shubin, “I’d set off looking for fossils, systematically inspecting every rock I saw for a scrap of bone at the surface. At the end of the day…. I had nothing, my empty bag a sign of how much I had to learn. (Shubin 63) But even after days walking and looking with an expert fossil finder who gave advice, it took time for Shubin to “see” the bones in rock. For days he asked questions and looked at the same rocks as the expert who found many and still came back emptyhanded each evening. Then finally, one day he discovered his first piece of bone, and it was only this discovery that made him actually understand what he was looking for. “The difference was this time I finally saw it, saw the distinction between rock and bone” (Shubin 64-65).

After this, it was much easier for Shubin to discover fossilized bones, but still the search is tedious and difficult. Even after a haul of some promising rock during his first self-led expedition, Shubin was not hopeful. To his great surprise, he was hailed as a hero once the fossils were delicately revealed in the rock formation, and it was discovered that he had found a skeleton of a tiny ancient reptile, tritheledont. From the teeth and jaws on this fossil it could be derived that this was a breakthrough for the reptile as there was tooth-on-tooth occlusion.

But once again, Shubin learned a greater lesson from this discovery that happened not in the field but in the lab where the rock had been carefully manipulated to reveal the fossil within. “…I learned that some of the biggest discoveries happen in the hands of fossil preparators, not in the field” (Shubin 70). Fossil preparators are important and perform a very tedious job. In fact, this is one of the reasons fossil hunting is so difficult. Difficult to find, and difficult to prepare for study and viewing. The key point is that the early mammals were small. Very small…. If the tooth was covered by a crumb of rock or even by a few grains of sand, you might never see it” (Shubin 66). Thus, it is easy to see how fossil, especially tooth fossil, hunting is extremely difficult. It takes patience and experience and an eye for tiny details. As Shubin reveals, it takes a team of hunters and preparators to discover the most important findings. Without both, evolution would be missing an imperative study, the study of teeth and jaws.