Early humans had 'jaws of steel'

February 3, 2009

Computer simulation shows early humans had jaws to eat diet of hard seeds and nuts

Your mother always told you not to use your teeth as tools to open something hard, and she was right. Human skulls have small faces and teeth and are not well-equipped to bite down forcefully on hard objects. Not so of our earliest ancestors, say scientists. New research published in the February 2009 issue of Proceedings of the National Academy of Sciences reveals nut-cracking abilities in our 2.5-million-year-old relatives that enabled them to alter their diet to adapt to changes in food sources in their environment. Compressive stress in the cranium of Australopithecus africanus Download Full Image

Mark Spencer, an Arizona State University assistant professor, and doctoral student Caitlin Schrein in ASU's School of Human Evolution and Social Change, are part of the international team of researchers who devised the study featured in the article "The feeding biomechanics and dietary ecology of Australopithecus africanus." Using state-of-the-art computer modeling and simulation technology - the same kind engineers use to simulate how a car reacts to forces in a front-end collision - evolutionary scientists built a virtual model of the A. africanus skull and were able to see just how the jaw operated and what forces it could produce.

"We started with a CT scan of a skull that is one of the most complete specimens of A. africanus that we have," said Spencer, researcher in ASU's Institute of Human Origins and a lead investigator on the project, which was funded by the National Science Foundation and European Union. This would be a later ancestor of Lucy - STS5 - who is affectionately known as "Mrs. Ples." The skull, discovered in 1947, has struts on the side of the nose, but no teeth. "We meshed those data with another specimen with teeth to make the virtual model of the bone and tooth structure.

"Then we looked at chimpanzees, who share common features with Australopithecus, and took measurements of how their muscles work and added that to the model. We were able to validate this model by comparing it to a similar model built for a species of monkey called macaques," Spencer explained.

The result - a rainbow colored virtual skull that illustrates forces absorbed by the cranial structure in simulated bite scenarios and how their unusual facial features were ideally suited to support the heavy loads of cracking hard nuts.

"It was like watching ‘Mrs. Ples' come to life," Spencer said.

"This reinforces the body of research indicating that facial specializations in species of early humans are adaptations due to a specialized diet," said Spencer. "The enlargement of the premolars, the heavy tooth enamel and the evidence now that they were loading forcefully on the premolars suggest the size of the objects were larger than the previously hypothesized small seeds and nuts.

"These ‘fall back' foods - hard nuts and seeds - were important survival strategies during a period of changing climates and food scarcity," he added. "Our research shows that early, pre-stone tool human ancestors solved problems with their jaws that modern humans would have solved with tools."

The Institute of Human Origins in ASU's College of Liberal Arts and Sciences is renowned for its ground-breaking research on our earliest human ancestors. Don Johanson, the institute's founding director and discoverer of "Lucy," recently completed a new book co-authored with Kate Wong, writer and editor at Scientific American. Due to hit the shelves in March, the book "Lucy's Legacy: The quest for human origins" picks up where Johanson's previous work, "Lucy: The beginnings of humankind," left off, exploring the latest thinking on human species evolution and the current state of paleoanthropology.

Writing faculty to read from work at ASU

February 4, 2009

Six writers, who are on the faculty of the 2009 Desert Nights, Rising Stars writing conference at Arizona State University, will read from their work on four evenings, beginning Feb. 18.

The readings will be held at 7:30 p.m. in Old Main’s Carson Ballroom on the Tempe campus. Admission is $10, payable at the door. Advance sale tickets are available online until Feb. 10 and by phone until Feb. 17.

The schedule includes:

Wednesday, Feb. 18 – Poet Nancy Mairs.

Thursday, Feb. 19 – Novelist Percival Everett and poet Mary Ruefle.

Friday, Feb. 20 – Nonfiction writer Meredith Hall and poet Natasha Trethewey.

Saturday, Feb. 21 – Novelist Alice Sebold.

Desert Nights, Rising Stars, is sponsored by the Virginia G. Piper Center for Creative Writing at ASU. For more information about the conference or readings, call (480) 965-6018 or go to www.asu.edu/piper.http://www.asu.edu/piper">www.asu.edu/piper. />

Writer Bios:

Nancy Mairs grew up north of Boston and received the A.B. cum laude from Wheaton College. She earned her doctorate from the University of Arizona and has taught at the University of Arizona and University of California, Los Angeles. She is a poet and essayist. Her most recent works includes a memoir, “Remembering the Bone House”; a spiritual autobiography, “Ordinary Time: Cycles in Marriage, Faith, and Renewal”; and three more books of essays: “Carnal Acts,”  “Voice Lessons: On Becoming a (Woman) Writer,” and “Waist-High in the World: A Life Among the Nondisabled.”

Percival Everett is the author of 15 novels, three collections of short fiction, and one volume of poetry. Among his novels are “Wounded,” “Glyph,” “Erasure,” “American Desert,” “For Her Dark Skin,” “Zulus” and “God’s Country.” His stories have been included in the Pushcart Prize Anthology and Best American Short Stories. He currently teaches at the University of Southern California.

Mary Ruefle is the author of 20 poetry collections; her most recent work is a book of prose, “The Most of It” (Wave Books, 2008). She also makes one-of-a-kind erasure books, using discarded nineteenth century texts, many of which have been exhibited in galleries and museums and sold into private collections. She is the recipient of NEA and Guggenheim fellowships, a Whiting Award, and an Award in Literature from The American Academy of Arts and Letters. She lives in southern Vermont.

Meredith Hall graduated from Bowdoin College at the age of 44. She wrote her first essay, “Killing Chickens,” in 2002. Two years later, she won the $50,000 Gift of Freedom Award from A Room of Her Own Foundation, which gave her the financial freedom to devote time to “Without a Map,” her first book. Her other honors include a Pushcart Prize and notable essay recognition in Best American Essays. She teaches writing at the University of New Hampshire and lives in Maine.

Natasha Trethewey is author of “Native Guard,” for which she won the 2007 Pulitzer Prize; “Bellocq’s Ophelia,” which was named a Notable Book for 2003 by the American Library Association; and “Domestic Work.” She is the recipient of fellowships from the Guggenheim Foundation, the Rockefeller Foundation Bellagio Study Center and other sponsors. Currently, she is Phillis Wheatley Distinguished Chair in Poetry at Emory University. Her first collection of poetry, Domestic Work (2000), was selected by Rita Dove as the winner of the inaugural Cave Canem Poetry Prize for the best first book by an African American poet.

Alice Sebold’s first book, “The Lovely Bones,” had an international impact, which is a rarely attained achievement – particularly for a book that focuses on subjects of rape, child murder, and the dissolution of families. Three months after the publication of “The Lovely Bones,” Sebold’s 1999 memoir “Lucky,” an account of her rape at the age of 18 and the trial that followed, was issued in paperback. Born in Madison, Wisconsin, Sebold grew up in the suburbs of Philadelphia and attended Syracuse University as well as the University of Houston and UC Irvine. Download Full Image