I agree with you Rachel. Baby's tongue use shapes the palate and teeth.  The "evolutionary" changes you see in the human genome arise from mutations that are then passed in the DNA code.  External changes (such as orthodontics) are not passed into the genome.

-----Original Message-----
From: Lactation Information and Discussion [mailto:[log in to unmask]] On Behalf Of Rachel Myr
Sent: Sunday, September 30, 2012 10:54 AM
Subject: Evolutionary changes

Heather, I think Pat is right about early feeding making its mark on anatomy. Pat, I got the impression you disagreed with the claim that this is due to evolution (as do Heather and I) but that you confirm the existence of an individual effect, as do I.
The way we use our bodies affects how they look. I noticed long ago that speakers of US English have less developed oral musculature than do speakers of French or Norwegian or Swedish or German or any other language that has hyper-rounded vowels. We use our lips, cheeks and tongues much more over here because we need to distinguish between at least a dozen diferent specific vowel sounds. In US English you can speak  correctly with a much more relaxed face :-) When you are alerted to this feature it is impossible NOT to notice it.

Our teeth stay healthier and better aligned if we bite and chew foods that offer resistance, like crusty bread, fresh produce, seeds, nuts or meat, rather than purees or that horrible squishy stuff sold sliced in sealed plastic bags that passes for bread in parts of the world. This also affects the way our orofacial muscles work.

It doesn't require genetic changes to have atrophied muscles or crooked teeth and the increasing prevalence of such problems does not suggest evolutionary change. That takes eons!
Rachel Myr
Kristiansand, Norway

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