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.

Review: The life after death of celebrity fossils

Review of: Seven Skeletons: The Evolution of the World’s Most Famous Human Fossils

Author: Lydia Pyne

Publisher: Viking

Source: Library

Grade: A

What does it take to turn a handful of anonymous bones into a personality? And not just any personality, but a celebrity with a worldwide following and century-long notoriety? A great discovery story helps. So does a catchy nickname. Add being in the right place at the right time, stir in a whole lot of luck, and those bones may rock the world, as science historian Lydia Pyne explains in Seven Skeletons, an examination of the after-lives of famous (and sometimes infamous) fossils that have changed our thinking about the course of human evolution.

The story opens with a jaw-dropping (literally) introduction to the Taung Child, who (or rather, whose skull) Pyne met on a winter morning in a human paleontology classroom in South Africa.

“(The professor) had pulled out several well-known fossil specimens from the university’s fossil vault,” Pyne writes, “setting them on flat wooden trays atop red velvet, showing them off like rare gems awaiting our appraisal as we filed into the room to take our seats. As students, we all had seen casts of these fossils before, but these were The Real Thing.”

Then, to the students’ amazement, the professor, one who had long been the Taung Child’s advocate in the face of paleontological skeptics of the 1920’s, “moved the little mandible up and down, clicking the fossil’s tiny front teeth together, and launched into a well-rehearsed comedy act of sorts that had the Taung Child telling a few jokes, commenting on the weather, and offering some insights about the early days of paleoanthropology. . . ” to its audience.

It was as if the bones of a hominin child, dead for millions of years, had a life of their own. As in a way, they did.

And they had a story to tell, as do the other bones in Pyne’s celebrity fossil ensemble – the Old Man of La Chapelle, representing the Neanderthals; Australopithecus Lucy, the show’s acknowledged diva; “hobbit” hominin Flo; the mysteriously absent Peking Man; and ingénue newcomer Sediba, also from South Africa, discovered in almost Hollywood style by a young boy and his dog.

The story even has a villain, the piece of fakery known as Piltdown Man, whose finding in the early 20^th century initially upstaged the Taung Child. Although no less a figure than Charles Darwin had suggested Africa as the original home of humanity, European chauvinism rejected the possibility of ancestors from the dark continent. By the end of the 19^th century, France and Germany could lay claim to a near-missing link between apes and humans in the form of Neanderthals. But Great Britain longed for a missing link of its own – an “earliest Englishman,” as newspapers would proclaim.

Paleologists expected a large brain to be the first indication of pre-human origins. The discovery of an apparently big-brained near-human fossil in an English gravel pit in 1912 fit expectations as if made to order. As in fact, it was.

Piltdown image: wikipedia

How could the Taung Child, a “moppet” of a bipedal but small-brained hominin discovered in South Africa in 1924, compete? Not until scientific work in the 1950’s revealed Piltdown to be a hoax did the Child take its proper place in prehistory as a human ancestor on a par with Lucy and her like.

(One of the illustrations of this post is a 1915 painting of Piltdown's finder and proponents. On the wall behind them, a portrait of Charles Darwin looks on, perhaps in horror.)

“The story of the Taung Child is practically apocryphal in paleoanthropology,” Pyne writes. “These stories function as part of the science’s own identify and values (‘good science wins out over detractors’), but the stories also serve to create a heroic persona around (the discoverer) and the fossil itself. . . Just as sagas and epic journeys are ways for audiences to become invested in the hero’s quest, the journey of the Taung Child was embraced into a cultural narrative.”

As significant as the fossils’ stories is the trend begun by the Taung Child’s discoverer, Dr. Raymond Dart, of making fossils and knowledge about them, more accessible. The change only accelerates as the newest South African fossils, including Sediba, are made available through new methodologies such as 3-D scanning and printing, as well as timely publication of results and more open access to the fossils themselves. It’s becoming a whole new way of doing science.

I’ve been a fan of Pyne and her writing since I read her first book, The Last Lost World, co-written with her science journalist father, Stephen J. Pyne. Seven Skeletons is a smaller and more accessible volume, but it lives up to the stature of its sibling book with an equally thought-provoking look at the nature of science, history, culture, and, yes, celebrity.