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
Parallel computation provides deeper insight into brain function
27.03.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University
Big data approach to predict protein structure
27.03.2017 | Karlsruher Institut für Technologie (KIT)
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
27.03.2017 | Life Sciences
27.03.2017 | Life Sciences
27.03.2017 | Earth Sciences