Article: Human 'dental chaos' linked to evolution of cooking

From: Rich Travsky (traRvEsky_at_hotmMOVEail.com)
Date: 02/23/05 

Date: Wed, 23 Feb 2005 10:14:27 -0700

 http://www.newscientist.com/article.ns?id=dn7035

 Crooked and disordered teeth may be the result of people having evolved
 to eat relatively mushy cooked food, suggests new research.

 The disarray may have developed because evolutionary pressures affecting
 the size and shape of both the front teeth and jaw conflict with those
 influencing the back teeth. This means that there is often not enough
 space in the human jaw to accommodate all our teeth.

 By animal standards, human dentition is extraordinarily disordered, says
 anthropologist Peter Lucas of George Washington University in Washington
 DC, US.

 "The only body parts requiring regular surgery are the teeth," says Lucas.
 "It is extraordinary that the normal development of human teeth routinely
 fails to produce 'ideal' dentition," he says - and no one has yet been
 able to offer an explanation for this phenomenon.

 Human teeth are often spatially disarrayed or "maloccluded", accounting for
 the huge number of people who seek treatment from orthodontists. This
 disarray can lead to periodontal and gum disease, because it becomes more
 difficult to clear food particles from the mouth.

 Teeth can also be missing - wisdom teeth simply do not have enough space to
 fit into the jaw, and sometimes do not form at all. In contrast most other
 mammals - including our close relatives, the great apes - have very low
 frequencies of malocclusion, Lucas told New Scientist.

 Lucas's theory is that human dentition began to go haywire soon after our
 early Homo ancestors learnt to chop and process food with simple tools and,
 later, to cook it. These processes greatly decrease the size and toughness
 of food. Lucas estimates, for example, that molars can be between 56% and
 82% smaller when eating cooked potato rather than raw.

 The front teeth and jaws are primarily occupied with reducing food to a
 small enough size to consume, whereas the molars and premolars at the back
 of the mouth are used to grind down tough particles.

 Lucas, speaking on Saturday at the American Association for the Advancement of
 Science meeting in Washington, DC, US, argued that since the advent of cooking
 these two processes have fallen out of sync.

 "The size of particles has reduced more rapidly than the rate at which the
 [toughness] of food has changed," he says. In response the human jaw may have
 shrunk beyond the point where it can hold all the molars required to
 successfully chew tough food. Lucas will now test the idea by measuring the
 particle size and toughness of food eaten by different animals and correlating
 these with tooth and jaw measurements.
 ...
 Anthropologists have not been able to agree on when our earliest ancestors
 started to prepare food. Current estimates place the advent of cooking anywhere
 between 2 million and 300,000 years ago.

Relevant Pages

  • Re: Article: Human dental chaos linked to evolution of cooking
    ... horse fossils - bridling of horses changes both the jaw structure and dental ... > Crooked and disordered teeth may be the result of people having evolved ... > to eat relatively mushy cooked food, ... > anthropologist Peter Lucas of George Washington University in Washington ...
    (sci.anthropology.paleo)
  • Re: Article: Human dental chaos linked to evolution of cooking
    ... > Crooked and disordered teeth may be the result of people having evolved ... > to eat relatively mushy cooked food, ... > space in the human jaw to accommodate all our teeth. ... > anthropologist Peter Lucas of George Washington University in Washington ...
    (sci.anthropology.paleo)
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    ... The Origins of the Modern Human Diet: ... comes from examinations of their teeth. ... is looking at the mechanics of the teeth and jaw. ... > to eat relatively mushy cooked food, ...
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