In the wake of a mass extinction like the one that occurred 445 million years ago, a common assumption is that surviving species tend to proliferate quickly into new forms, having outlived many of their competitors.
But new research shows that tiny marine organisms called graptoloids did not begin to rapidly develop new physical traits until about 2 million years after competing species became extinct. (more…)
*Climate changes profoundly influenced the rise and fall of six distinct, successive waves of mammal species diversity in North America over the last 65 million years, shows a novel statistical analysis led by Brown University evolutionary biologists. Warming and cooling periods, in two cases confounded by species migrations, marked the transition from one dominant grouping to the next.*
PROVIDENCE, R.I. [Brown University] — History often seems to happen in waves — fashion and musical tastes turn over every decade and empires give way to new ones over centuries. A similar pattern characterizes the last 65 million years of natural history in North America, where a novel quantitative analysis has identified six distinct, consecutive waves of mammal species diversity or “evolutionary faunas.” What force of history determined the destiny of these groupings? The numbers say it was typically climate change.
“Although we’ve always known in a general way that mammals respond to climatic change over time, there has been controversy as to whether this can be demonstrated in a quantitative fashion,” said Christine Janis, professor of evolutionary biology at Brown University. “We show that the rise and fall of these faunas is indeed correlated with climatic change — the rise or fall of global paleotemperatures — and also influenced by other more local perturbations such as immigration events.” (more…)
*Rats free trapped companions, even when given choice of chocolate instead*
The first evidence of empathy-driven helping behavior in rodents has been observed in laboratory rats that repeatedly free companions from a restraint, according to a new study by University of Chicago neuroscientists.
The observation, published today in Science, places the origin of pro-social helping behavior earlier in the evolutionary tree than previously thought. Though empathetic behavior has been observed anecdotally in non-human primates and other wild species, the concept had not previously been observed in rodents in a laboratory setting. (more…)
The political outlook of blacks in America has undergone dramatic swings in the last ten years — from the depths of powerlessness during the aftermath of Hurricane Katrina, to the zenith with the election of the first black president, Barack Obama.
Now, with another presidential election looming, blacks are again confronting new issues as they judge and sometimes question the impact of Obama’s election, contends UChicago political scientist Michael Dawson, whose work finds sharp contrasts between how African Americans and whites feel about their country. (more…)
An international research team has discovered that a pervasive human RNA modification provides the physiological underpinning of the genetic regulatory process that contributes to obesity and type II diabetes.
European researchers showed in 2007 that the FTO gene was the major gene associated with obesity and type II diabetes, but the details of its physiological and cellular functioning remained unknown. (more…)
Birds may have a more highly developed sense of smell than researchers previously thought, contend scholars who have found that penguins may use smell to determine if they are related to a potential mate.
The research by the University of Chicago and the Chicago Zoological Society, which manages Brookfield Zoo, shows how related birds are able to recognize each other. The study, published Wednesday, Sept. 21 in the article, “Odor-based Recognition of Familiar and Related Conspecifics: A First Test Conducted on Captive Humboldt Penguins (Spheniscus humboldti),” in the journal PLoS ONE, could help conservationists design programs to help preserve endangered species.
“Smell is likely the primary mechanism for kin recognition to avoid inbreeding within the colony,” said Heather Coffin, lead author of the paper. (more…)
Pegloticase, a modified porcine enzyme, can produce significant and sustained clinical improvements in two out of five patients with chronic gout that is resistant to conventional therapies, researchers report in the Aug. 17 issue of JAMA.
In two controlled clinical trials, pegloticase rapidly lowered high levels of uric acid, the biochemical abnormality in gout, and kept it in the normal range for six months or more in 42 percent of patients receiving the drug every two weeks. Forty percent of patients had complete resolution of at least one of the painful swollen joint nodules, known as tophi, a hallmark of severe gout. (more…)
*Study finds stress boosts performance for confident students, but holds back those with more anxiety*
Knowing the right way to handle stress in the classroom and on the sports field can make the difference between success and failure for the millions of students going back to school this fall, new University of Chicago research shows.
“We found that cortisol, a hormone released in response to stress, can either be tied to a student’s poor performance on a math test or contribute to success, depending on the frame of mind of the student going into the test,” said Sian Beilock, associate professor in psychology and one of the nation’s leading experts on poor performance by otherwise talented people. (more…)
