Posts tagged National Science Foundation
ANCIENT BIPEDAL HOMINID DUBBED ‘NUTCRACKER MAN’ PREFERRED GRASS TO NUTS, NEW STUDY FINDS
May 2nd
The hominid, known as Paranthropus boisei, ranged across the African landscape more than 1 million years ago and lived side-by-side with direct ancestors of humans, said University of Colorado Boulder anthropology Professor Matt Sponheimer, a study co-author. It was long assumed Paranthropus boisei favored nuts, seeds and hard fruit because of its huge jaws, powerful jaw muscles and the biggest and flattest molars of any known hominid in the anthropological record, he said.
In the last several years, research on the wear marks of teeth from Paranthropus boisei by other research teams has indicated it likely was eating items like soft fruit and grasses, said Sponheimer. That evidence, combined with the new study that measured the carbon isotopes embedded in fossil teeth to infer diet, indicates the rugged jaw and large, flat tooth structure may have been just the ticket for Paranthropus boisei to mow down and swallow huge amounts of grasses or sedges at a single sitting, he said.
“Frankly, we didn’t expect to find the primate equivalent of a cow dangling from a remote twig of our family tree,” said Sponheimer.
Published in the May 2 issue of the Proceedings of the National Academy of Sciences, the study was led by University of Utah Professor Thure Cerling. Other authors included Emma Mbua, Frances Kirera, Fredrick Manthi and Meave Leakey from the National Museums of Kenya, Fredrick Grine from Stony Brook University in New York and Kevin Uno from the University of Utah.
“Fortunately for us, the work of several research groups over the last several years has begun to soften prevailing notions of early hominid diets,” said Sponheimer. “If we had presented our new results at a scientific meeting 20 years ago, we would have been laughed out of the room.”
For the new study, the researchers removed tiny amounts of enamel from 22 Paranthropus boisei teeth collected in central and northern Kenya, each of which contained carbon isotopes absorbed from the types of food eaten during the lifetime of each individual. In tropical environments, virtually all trees and bushes — including fruits and leaves — use the so-called C3 photosynthetic pathway to convert sunlight into energy, while savannah grasses and some sedges use the C4 photosynthetic pathway.
The isotope analysis indicated Paranthropus boisei individuals were much bigger fans of C4 grasses and sedges than C3 trees, shrubs and bushes. The results indicated the collective diet of the 22 individuals averaged about 77 percent grasses and sedges for a period lasting at least 500,000 years, said Sponheimer.
The research team also compared the carbon isotope ratios of Paranthropus teeth with the teeth of other grazing mammals living at the same time and in the same area, including ancestral zebras, hippos, warthogs and pigs. The results indicated those mammals were eating primarily C4 grasses, virtually identical to Paranthropus boisei. “They were eating at the same table,” said Cerling.
Paranthropus was part of a line of close human relatives known as australopithecines that includes the famous 3-million-year-old Ethiopian fossil Lucy, seen by some as the matriarch of modern humans. Roughly 2.5 million years ago, the australopithecines are thought to have split into the genus Homo — which produced modern Homo sapiens — and the genus Paranthropus, that dead-ended, said Sponheimer.
“One key result is that this hominid had a diet fundamentally different from that of all living apes, and, by extension, favored very different environments,” he said. “And having a good idea of where these ancient creatures lived and what they ate helps us understand why some early hominids left descendants and others did not.”
The first skull of a Paranthropus boisei individual was discovered by co-author Meave Leakey’s in-laws, Mary and Louis Leaky, in 1959 in Tanzania.
In 2006, a team led by Sponheimer found that a cousin of Paranthropus boisei known as Paranthropus robustus had a far more diverse diet than once believed, clouding the notion that it was driven to extinction by its picky eating habits. Published in Science magazine, the study showed that Paranthropus robustus had a diverse diet ranging from fruits and nuts to sedges, grasses, seeds and perhaps even animals.
So what led to the end of the line for Paranthropus? It could well have been direct competition with Homo — which was becoming skilled in extensive bone and stone technology — or it could have been a variety of other issues, including a slower reproductive rate for Paranthropus than for Homo, he said.
The new study was funded by the National Science Foundation and the CU-Boulder Dean’s Fund for Excellence.
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WHO WANTS TO DELIBERATE WITH POLITICIANS? MORE THAN SOME EXPECTED, STUDY FINDS
Apr 4th
Given that, the thinking goes, it’s reasonable to conclude that citizens want less, not more, involvement in politics.
But that widely accepted theory does not survive empirical scrutiny, a team of researchers that includes a University of Colorado Boulder political scientist found.
Rather than rejecting political discourse, most people express strong interest in deliberating with real politicians, the team found. Further, when citizens are offered the chance to discuss political issues with their legislators, significant numbers do.
The view of the American public as desperate to avoid politics is “deeply misleading,” the team wrote in a recent edition of American Political Science Review. The work joins a growing number of studies applying empirical analysis to political theories of deliberative democracy.
The team was led by Michael Neblo of Ohio State University and included Kevin Esterling of the University of California, Riverside, Ryan Kennedy at the University of Houston, David Lazer of Northeastern University and Harvard University, and Anand Sokhey of CU-Boulder.
Sokhey and his colleagues suggest that some political theorists reached an erroneous conclusion because they started with the wrong question, namely, “Who actually deliberates?”
The answer, of course, is that few people engage in deliberative democracy.
But Sokhey’s team essentially posed a different question: “Who is willing to deliberate?” The team found that large majorities of citizens, even those disgusted by politics, are willing to participate—and, when given the chance, many do.
Sokhey puts it this way: “If people perceive politicians to be more responsive and less corrupt … would people be more willing to be involved?” The answer is yes. “They’re happy to be involved.”
That was surprising, he says, adding that the kinds of people who wanted to participate also was unexpected. The traditional view is that people who are older, wealthier, well-educated and white are more likely to become engaged in politics.
“We don’t find that a lot of that holds here,” Sokhey says.
The team found that younger people and non-whites were willing to join political deliberations.
The researchers set out to test two competing theories of political involvement. One theory, dubbed “stealth democracy,” holds that people are often disgusted by politics, believe politicians are generally corrupt, and that when they do join the political process, they do so largely to thwart political corruption.
If politics were less corrupt, the theory holds, citizens would happily retreat to their private lives and let government run quietly and efficiently in the background.
But the theory of stealth democracy contradicts one of the deliberative theory’s central claims: that citizen apathy is actually caused by frustration and disempowerment in the system. “If the political process could be rendered more rational and responsive in their eyes, then they would be moreinclined to engage in it robustly,” the authors write, adding:
“The disagreement between the stealth thesis and the deliberative thesis could hardly be clearer, and the stakes on which is right could hardly be higher.”
The research team began with hypothetical questions posed to 404 subjects.
For instance, they asked the following: “If politics were [less/more] influenced by self-serving officials and powerful special interests, do you think that you would be more or less interested in getting involved in politics?” Respondents indicated their interest on a 1-5 scale.
Those who would participate less if politics were less corrupt fit the stealth-democracy thesis. Those who would participate more fit the deliberative thesis.
The results were significant. Eight times more people fit the deliberative profile than the stealth profile, suggesting that the “stealth” view is not widely held.
But that was just the response to items about stealth vs. deliberative attitudes. When the researchers made a real offer to deliberate with a real member of Congress, 65 percent agreed.
The study’s participants were offered the chance to deliberate online with their congressional representative. The members of Congress came from 12 congressional districts spread across four major geographic regions. The politicians included five Republicans and seven Democrats who were ideologically diverse.
Most surprisingly, the authors note, both those holding “stealth” and “deliberative” views were eager to discuss politics with real politicians. But according to the stealth thesis, such eagerness should have been found mostly among deliberative democrats.
The explanation, the authors conclude, is that “People do not really hold stealth democracy as their first preference. Instead, they will settle for stealth democracy if the civics-textbook version of deliberative representative democracy is not achievable.”
The work of Neblo, Sokhey and the rest of the team was funded by a grant from the Digital Government Program of the National Science Foundation.
Read more on this story soon in Colorado Arts & Sciences Magazine at http://artsandsciences.colorado.edu/magazine/.
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