Ask A Scientist© Biology Archive

name Becky
status other
grade other
location NV

Question - So, my question is about wisdom teeth. What exactly are
they for if all we do is get them pulled? What is their signifigance and
why hasn't evolution weeded them out of our bodies? Also, why do we get
them at such a late age?
---------------------------------------
 This is a great example of structures that are in transition and that 
humans are still in the process of evolving. If you compare the skull of an 
ancient human, such as Neanderthals, with a modern human the jaw in the 
ancient human was more massive. This probably was due to the food sources 
that were available that required more force in chewing. As food sources 
changed, if the jaw started becoming smaller due to mutation it wouldn't 
affect survival. Remember, structures don't go away* because* they aren't 
used anymore. If they DO start to change AND it doesn't affect survival it 
doesn't matter. So, as the jaw became smaller, that doesn't necessarily mean 
the teeth would automatically also start to go away. These are separate 
structures under the control of separate genes. But that does mean that 
there is not as much room in the jaw for them. Some people don't have wisdom 
teeth-this would have been a disadvantage to a Neanderthal, but isn't for 
Homo sapiens. I only had 3 wisdom teeth. Why do they come in later in life? 
Not sure, but they are genetically programmed to do so.

vanhoeck
====================================================================