Study: Evolution may not save some species
DAVIS, Calif., June 8 (UPI) -- U.S. researchers studying a tiny seashore creature say animals and plants may not be able to evolve their way out of the threat posed by climate change.
Scientists at the University of California, Davis, said the tide pool copepod Tigriopus californicus -- found from Alaska to Baja California -- showed little ability to evolve heat tolerance in a lab study.
"This is a question a lot of scientists have been talking about," said study co-author Eric Sanford, an associate professor of evolution and ecology at UC Davis. "Do organisms have the ability to adapt to climate change on a timescale of decades?"
UC Davis graduate student Morgan Kelly, the first author of the paper, collected copepods from eight locations between Oregon and Baja California in Mexico and grew the short-lived shrimp-like copepods in the lab for 10 generations, subjecting them to increased heat stress to select for more heat-tolerant animals, a UC Davis release issued Wednesday said.
Kelly was able to coax only about 1 degree Fahrenheit of increased heat tolerance over the 10 generations, and in most groups the increase in heat tolerance had hit a plateau before that point.
Individual populations of the copepods are very isolated, the researchers said, meaning there is very little flow of new genes for evolutionary flexibility across the population as a whole.
"It's been assumed that widespread species have a lot of genetic capacity to work with, but this study shows that may not be so," said co-author Rick Grosberg, professor of evolution and ecology at UC Davis.
"The critical point is that many organisms are already at their environmental limits, and natural selection won't necessarily rescue them," Grosberg said.
Study: Minorities bigger media consumers
EVANSTON, Ill., June 8 (UPI) -- Minorities ages 8 to 18 consume an average of 13 hours of media content a day, much more than their white counterparts, U.S. researchers say.
In the first national study to focus exclusively on children's media use by race and ethnicity, researchers at Northwestern University found minority children spend an average 4 1/2 more hours a day consuming media.
"In the past decade, the gap between minority and white youth's daily media use has doubled for blacks and quadrupled for Hispanics," said Ellen Wartella, who directed the study and heads the Center on Media and Human Development in the School of Communication.
"The big question is what these disparities mean for our children's health and education."
The study found minority children spend 1 to 2 additional hours each day watching TV and videos, about an hour more listening to music, up to an hour and a half more on computers, and 30 to 40 minutes more playing video games than their white counterparts, a Northwestern release said Wednesday.
"Our study is not meant to blame parents," says Wartella. "We hope to help parents, educators and policymakers better understand how children's media use may influence health and educational disparities."
U.N. marks World Oceans Day
UNITED NATIONS, June 8 (UPI) -- The U.N. secretary-general marked World Oceans Day Wednesday by urging all governments and peoples to protect the world's oceans for future generations.
In a statement issued to mark World Oceans Day being celebrated around the globe, Secretary-General Ban Ki-moon outlined what he called "many severe challenges" related to oceans.
"These range from depleted fishery resources, the impacts of climate change and the deterioration of the marine environment to maritime safety and security, labor conditions for seafarers and the increasingly important issue of migration by sea," Ban said.
"All activities and policies related to oceans and the marine environment need to acknowledge and incorporate the three pillars of sustainable development: environmental, social and economic.
"Only then can we achieve the development objectives set by the international community.
"I urge governments and all sectors of society to embrace our individual and collective responsibility to protect the marine environment and manage its resources in a sustainable manner for present and future generations," Ban said.
To mark the day, U.N. agencies would "join hundreds of aquariums, zoos, museums, conservation organizations, and thousands of individuals around the world celebrating the day by participating in fun, inspirational, and educational events," the release said.
Late diagnosis of HIV said a threat
ATLANTA, June 8 (UPI) -- A fifth of people with HIV don't know it, and a third of them are diagnosed so late in their infection they develop AIDS within one year, U.S. officials say.
Some states with the largest incidence of the human immunodeficiency virus also have large numbers of infected people who aren't diagnosed, USA Today reported Wednesday.
The states with the greatest number of late diagnoses are Florida, New York, Texas, Georgia and New Jersey, the newspaper said.
"There are tens of thousands of people in the U.S. who are diagnosed late, sometimes too late to save their lives, and certainly too late to help them avoid transmission to others," Jim Curran, dean of Emory University's Rollins School of Public Health in Atlanta, said.
The large number of undiagnosed cases still exists 30 years after the first cases of HIV/AIDS were reported by the Centers for Disease Control in 1981, two decades after the creation of the first HIV test and 15 years after the introduction of effective therapies.
About 236,400 of the 1.1 million people infected with HIV have not been diagnosed, but late diagnoses have declined 5 percent from 2001 to 2007, the CDC said.
"It's not where we'd like to be, but we're moving in the right direction," Kevin Fenton, the CDC's director of HIV/AIDS prevention, said.