Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: paul.fr on 03/05/2008 17:10:54

Title: Where do teeth come from?
Post by: paul.fr on 03/05/2008 17:10:54

Are we born with all our teeth, just sitting there waiting to move up/down? If not, how are they made and on what signal?

Title: Where do teeth come from?
Post by: ukmicky on 04/05/2008 03:18:25

Dont know but changing the subject ever so slightly (sorry paul).

I wonder if it would be possible in the future to inject stems cells into your gums which would then grow and replace your missing teeth. I said your gums Paul as i know you like to experiment.

Title: Where do teeth come from?
Post by: JimBob on 04/05/2008 03:59:21

The latter would be ideal for me Michael, I am going for implants soon.

As for the origin - have you ever heard of evolution? Somewhere during the Devonian sharks were the first fish to developed teeth. The teleosts (bony fish) developed teeth independently (?????) in parallel evolution - unless there is ... (creepy music) ... a missing link to a previous chordate form of life that already had teeth. This is a more probable scenario as parallel evolution of such a fundamental chordate characteristic is rather unlikely.

Class Agnatha or jawless fish, the most primitive type of toothed fish known, occur very early in the fossil record - the Ordovician. Lampreys and hag fish are jawless fish.

But even before that, in the Cambrian, there are little fossil called "Conodonts" that could very well be teeth. They exist almost until the Triassic and are used extensively as time markers for the geologic time scale. Only within the last 20 years have the fossils of fish that had teeth of known conodonts been found. So the tooth has been around for at least 550 Million years. Conodonts are important fossils for the Paleozoic and geology in general.

For example, the International Commission on Stratigraphy defines the base of the Changhsingian Stage of the Permian System of the Lopingian Series AS (253.8 MA + or - 0.7 M years as a being based on a Conodont, near lowest occurrence of conodont Clarkina wangi, Base of Bed 4a-2, 88 cm above base of Changxing Limestone, Meishan D section (Zhejiang province, E. China) - Ratified 2005 - Episodes article in preparation. This represents just 6.6 million years of geology - that is + or - 1.4 million years.

(These guys are just anal. Can't stand discussing geology with a stratigrapher.)

Happy now, paul, or would you like to insult me some more? (I use the lower case as this guy doesn't deserve the upper case appellation.) Go ahead, everyone else does, even though I am the most erudite and cogent of the contributers to this forum.

 [;D] (sh1t eating grin)