Review: Here’s an evolutionary tale to chew on

Review of: Evolution’s Bite: A Story of Teeth, Diet, and Human Origin
Author: Peter S. Ungar
Publisher: Princeton University Press
Source: Dallas Public Library
Grade: A

Some sagas of human origins tell readers what scientists discovered. Peter S. Ungar tells how they discovered it, in Evolution’s Bite: A Story of Teeth, Diet, and Human Origins, his tale of the most common of human fossil remains – our teeth.

Less sexy than artistic reconstructions, or even iconic photographs of skeletons arranged against a black velvet background, teeth nevertheless have a lot of stories to tell. “They allow us to track changes from one species to the next to trace our evolutions,” Ungar writes. “We look to tooth size, shape, pattern of wear, and chemistry to work out details of the foods eaten by long-gone species. . . (and) the key to unlocking an extinct species’ place in nature.”

That’s the story Ungar has been chewing on for three decades, in travels around the world. From observations of the diets and ecology of modern primates – from monkeys to gorillas to present-day hunter-gatherers. From engineering analyses of the wear patterns of both fossil and modern teeth, to records of long term climate change embedded in the Greenland ice cap, to chemical signatures in the structure of teeth themselves, Evolution’s Bite ranges widely.

Along the way, Ungar touches on the history of the journey, on the famous names (Mary and Louis Leakey of fossil “Lucy” fame) and the lesser knowns (the “Forrest Gump meets Indian Jones” story of swashbuckling geologist/explorer Raphael Pumpelly).  

Some information upsets common assumptions. Mountain gorillas noted for the ability to utilize the tough plant foods for which they seem so well adapted will prefer to gobble soft, sugary fruits when those are available. Could the same phenomenon apply to fossil hominins?

Did early human guts compete with brains for the greater share of the energy available from our foods? Did we become dependent on the greater energy available from meat and cooked foods to make digestion less energy-expensive? (Ungar touches on this “expensive tissue” hypothesis while noting that it also has been called into question.)

Most intriguing of all, Ungar touches on the dietary changes – and accompanying social changes – that finally made our species truly human. Was it hunting? Gathering? New tools to collect and process food? Cooking? The sharing of meals? Our diets – and the teeth that chew them – were intimately involved in all facets of the process.

Finally, what pushed now fully-human beings to free themselves from the constraints of the “biosphere buffet” spread by nature, taking charge of our evolution by planting crops and raising animals for our food.

“Humans had earned a living by hunting and gathering wild foods for 10,000 generations,” Ungar writes, “but in a just a few, brief millennia, food production sprung up across the globe. . . (beginning) a cascade of events that gave humanity its greatest accomplishments, from the peanut butter sandwich to the deep-space probe.”

Yes, Ungar does have a sense of humor. But listing peanut butter sandwiches as a major milestone effectively compresses thousands of years of plant breeding and food processing technology into a few words. It’s an accomplishment well worth digesting. 

And, by the way, how do our dietary adaptions affect our current health, dental and otherwise? Ungar’s advice is something to savor.