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By Peter S. Ungar

Most of us only think about teeth when something’s wrong with them — when they come in crooked, break, or begin to rot. But take a minute to consider your teeth as the extraordinary feat of engineering they are. They concentrate and transmit the forces needed to break food, again and again, up to millions of times over a lifetime. And they do it without themselves being broken in the process — with the very same raw materials used to make the plants and animals being eaten.

Chewing is like a perpetual death match in the mouth, with plants and animals developing tough or hard tissues for protection, and teeth evolving ways to sharpen or strengthen themselves to overcome those defenses. Most living things don’t want to be eaten. They often protect themselves by reinforcing their parts to stop eaters from breaking them into small enough bits to swallow or digest. It could be a hard shell to keep a crack from starting, or tough fibers to keep one from spreading. Either way, the eater still has to eat. And that’s where teeth come in. The variety of tooth types, especially across the mammals, is extraordinary. It’s a testament to what evolution can accomplish given time, motive, and opportunity.

Lots of animals have “teeth”; sea urchins, spiders, and slugs all have hardened tissues used for food acquisition and processing. But real teeth, like yours and mine, are special. They first appeared half a billion years ago, and Nature has spent the whole time since tinkering with ways to make them better. It’s a story written in stone – the fossil record. We see the appearance of a hard, protective coating of enamel, better ways of attaching tooth to jaw, differentiation of front and back teeth, tighter fit between opposing surfaces, and a new joint for precise movements of the jaw.

The motive is endothermy; we mammals heat our bodies from within. And chewing allows us to squeeze the energy we need to fuel our furnaces. The opportunity is evolvability; very slight genetic tweaks can have dramatic effects on tooth form and function. Consider the incredible variety of different tooth types in mammals, matched so well to the foods individual species eat. A lion has sharp-crested chewing teeth, with blades opposing one another like a pair of scissors, for slicing flesh. A cow has broad, flat ones broken by thin, curved ridges, like a cheese grater, for milling grass. You and I have thick molars with rounded cusps that fit neatly into opposing basins, like a mortar and pestle, for crushing and grinding whatever it is we eat.

There can be little doubt that the diversity, abundance, and success of mammals, including us, are due, in no small measure, to our teeth. Look in a mirror, smile, and think about it.

Peter S. Ungar received his PhD in Anthropological Sciences from Stony Brook University and taught Gross Anatomy in the medical schools at Johns Hopkins and Duke before moving to the University of Arkansas, where he now serves as Distinguished Professor and Chairman of the Department of Anthropology. He has written or co-authored more than 125 scientific papers on ecology and evolution for books and journals and is the author of Teeth: A Very Short Introduction.

The Very Short Introductions (VSI) series combines a small format with authoritative analysis and big ideas for hundreds of topic areas. Written by our expert authors, these books can change the way you think about the things that interest you and are the perfect introduction to subjects you previously knew nothing about. Grow your knowledge with OUPblog and the VSI series every Friday, subscribe to Very Short Introductions articles on the OUPblog via email or RSS, and like Very Short Introductions on Facebook.

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Image credit: Gebitsdiagram Chart created with Open Dental By Jordan Sparks. CC-BY-SA-3.0 via Wikimedia Commons

The post Thinking more about our teeth appeared first on OUPblog.

        

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Well this one is a bit vague. Most people will argue that it depends on what you do with the apple. If you throw the apple at any approaching doctors, it should do the trick. However, if you eat it, most scientists would say, not much will happen. However recent studies have shown that eating apples can prevent the risk of breast and colon cancer.

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“Don’t go outside without a coat. Its Freezing! You’ll Catch A Cold!”

This is untrue. The Common Cold is a virus that is passed from human to human. It can be spread in hot and cold weather. What is true is that being cold lowers your resistance against viruses, but this doesn’t by any means suggest you will automatically catch a cold from being outside without a cold when it gets a bit nippy.

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This is also completely untrue. Believe it or not, there has been studies carried out on this. In a study carried out on 300 “knuckle crackers”, results found no evidence that this leads to arthritis. The strain put on your joints when you crack them are nothing compared to the normal strain put on them during everyday activities. In essence, it doesn’t do any damage at all, its just generally a very annoying habit.

“Eat up your carrots, you’ll be able to see in the dark!”

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“Dont swallow Chewing Gum! It doesn’t get digested. It will stay in your body forever!

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Well this one is a bit vague. Most people will argue that it depends on what you do with the apple. If you throw the apple at any approaching doctors, it should do the trick. However, if you eat it, most scientists would say, not much will happen. However recent studies have shown that eating apples can prevent the risk of breast and colon cancer.

“Eat up your crusts, they are good for you!”

Finally a proven, true fact. Although on the surface, this appears to be another tale told by your gran, crusts contain eight times as many antioxidents as any part of the bread. Interesting eh? So if you are that bothered, eat up your crusts!

“If you keep pulling faces, one day the wind will change and you’ll get stuck that way.

“

This one doesn’t even justify me wasting my time explaining why it is so proposterous. So I won’t.

“You only use 10% of your brain”

Wrong, Wrong, Wrong! The only people who only use 10% of their brain are the people who made up this myth. In many cases, it is hard to believe that some people are even using 10% of their brain. However, scientifically speaking, this is not true. Hi-tech studies have proven this. What may be true is that only 10% - or a figure around this - would be used at any one time, but all of the brain is used for different things at different times.

“Eating Low Fat foods help you lose weight”

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“I dare you to sneeze with your eyes open. I bet your eyes fly out our head!”

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Meanwhile check out my other articles -
* * *

Who was the best test batsman of all time? - http://sportales.com/cricket/best-test-batsmen-of-all-time/

Which is the best lottery game to play? Is there any skill involved at all? -

Premier League Statistics. The guide to win every sports pub quiz! - http://sportales.com/soccer/premier-league-statistics-you-never-needed-to-know-and-never-cared-that-existed/
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