Ungar will be part of a seminar that includes a panel of experts addressing different aspects of the evolution of human diet. The seminar is part of the American Association for the Advancement of Science meeting on Friday, Feb. 13, in Chicago.
“Teeth are perfect for testing diet hypotheses, because they are the best preserved items in the fossil record and are part of the digestive system,” said Ungar. “But until now, we haven’t had the technology to pull much information out of them.”
His work has found anatomical evidence to support some long-standing hypotheses – and in other cases has found evidence that suggests the current models are wrong.
“The models are fine in and of themselves, but we need to go further,” Ungar said. “We need to test them as hypotheses.” With his pioneering techniques, he has found a way to do just that.
Until recently, scientists counted the pits and scratches on teeth by looking at images from high-resolution electron microscopes. But such counts depended upon the expertise of the observer and often proved difficult to reproduce.
“The problem then is that you have to count and measure those features by hand, which introduces a high likelihood of human error. That's a very subjective process, and you're going to get variability between the measurements of any two researchers” Ungar said. “We needed an objective, automated, repeatable way to quantify wear on teeth.”
Ungar sought a more objective way to look at the wear and tear on teeth. He first developed a way of using software for geographic information systems to create a different kind of map – he used the software for dental topography, to show the mountains and valleys formed by the wear patterns on teeth. Just as GIS can be used to measure topographical features on a landscape, such as slope, elevation and aspect, Ungar found it could analyze dental features that are important to chewing and processing foods. In particular, Ungar and his colleagues used GIS to calculate slope and angularity values for each tooth; slope refers to the steepness of a tooth cusp, whereas angularity is a measure of overall jaggedness.
In 2003, Ungar increased the resolution of his measurements by using a white light scanning confocal microscope. The length, width and even depth information about specific features is automatically and objectively recorded by the instrument.
The detailed, three-dimensional information allows researchers to determine characteristics of the surface, such as roughness and directionality of the wear using fractal analyses borrowed from mechanical engineering.
Ungar combines his high-tech work with old-fashioned fieldwork. He has logged thousands of hours in forests in Central and South America as well as Indonesia observing the diets of different apes and monkeys. Researchers can then tranquilize or examine museum specimens of the animals and use the same dental techniques employed to make crowns to create high-resolution molds of primate teeth using epoxy. Ungar also has created dental impressions of some of the world’s most famous fossil ancestors, including AL-288-1, better known as “Lucy,” the famed Taung child, and OH-5, known as “Nutcracker Man.”
This work has resulted in a repository of hundreds of tooth impressions. Using this library of teeth, he can compare what modern-day primates eat and the wear patterns on their teeth to the wear patterns on fossil teeth to get direct evidence of what types of foods they were eating.CONTACTS:
Melissa Lutz Blouin | Newswise Science News
Further reports about: > Dental Analytics > Evolution > Human > dental topography > diet hypotheses > digestive system > electron microscope > geographic information systems > high-resolution electron microscopes > molds of teeth > monkeys > steepness of a tooth cusp > white light scanning confocal microscope
First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife
Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering