MIAMI — The mass extinction that obliterated three-fourths of life on Earth due to the strike of massive asteroid millions of years ago, including non-avian dinosaurs, set the stage for the swift rise of frogs, said a study that shows how frogs became among the most diverse vertebrates in the world.
According to a study published this week in the Proceedings of the National Academy of Sciences, the slimy amphibians exploded in numbers and diversified in the millions of years after a massive asteroid wiped out the dinosaurs, taking advantage of the huge holes in the ecosystem that extinct creatures left behind.
An international team of researchers presented a new tree of life for frogs that helps solve longstanding riddles about relationships and sheds light on the history and pace of frog evolution.
As many as 10 types of frogs are believed to have survived the mass extinction some 66 million years ago, which erased three-quarters of life on Earth, said the report.
Unexpectedly, their analyses showed three major lineages of modern frogs — about 88 percent of living species — appeared simultaneously, evolving on the heels of the extinction event that marked the end of the Cretaceous Period and the beginning of the Paleogene.
Previous research suggested a more ancient origin of many of these modern frog groups.
“Frogs have been around for well over 200 million years, but this study shows it wasn’t until the extinction of the dinosaurs that we had this burst of frog diversity that resulted in the vast majority of frogs we see today,” said study co-author David Blackburn, associate curator of amphibians and reptiles at the Florida Museum of Natural History on the University of Florida campus.
“This finding was totally unexpected.”
Scientists, until now, believed that most modern frog species emerged at a steady pace between 66 million and 150 million years ago. But the latest research shows frogs burst onto the scene more like an “explosion,” as the tiny amphibians swept into habitats left vacant by other creatures.
The speed at which frogs diversified after the asteroid or comet impact that triggered a massive die-off of most plant and animal life suggests that the survivors were probably filling up new niches on Earth, Blackburn said.
“We think there were massive alterations of ecosystems at that time, including widespread destruction of forests,” he said.
“But frogs are pretty good at eking out a living in microhabitats, and as forests and tropical ecosystems rebounded, they quickly took advantage of those new ecological opportunities.”
Frogs rose to become one of the most diverse groups of vertebrates, with more than 6,700 described species. But sparse genetic data has hindered scientists from reliably tracing their evolutionary history and the links between frog families.Follow @gorkhapost
Android apps may be illegally tracking children, study finds
Over 3300 free and popular children’s Android apps available on the Google Play Store could be violating child privacy laws, according to a new, large-scale study, highlighting growing criticism of Silicon Valley’s data collection efforts.
Researchers using an automated testing process have discovered that 3,337 family and child oriented Android apps on Google Play were improperly collecting kids’ data, potentially putting them in violation of the US’ Children’s Online Privacy Protection Act, or COPPA law (which limits data collection for kids under 13).
Only a small number were particularly glaring violations, but many apps exhibited behavior that could easily be seen as questionable.
Researchers analyzed nearly 6,000 apps for children and found that 3,337 of them may be in violation of the COPPA, according to the study report. The tested apps collected the personal data of children under age 13 without their parent’s permission, the study found.
“This is a market failure,” said Serge Egelman, a co-author of the study and the director of usable security and privacy research at the International Computer Science Institute at the University of California, Berkeley.
“The rampant potential violations that we have uncovered points out basic enforcement work that needs to be done.”
The researchers are adamant that they’re not showing ‘definitive legal liability.’ These apps may be running afoul of the law, but it’s up to regulators at the FTC to decide if they are. Without iOS data, it’s also unclear how common this problem is across platforms.
The potential violations were abundant and came in several forms, according to the study. More than 1,000 children’s apps collected identifying information from kids using tracking software whose terms explicitly forbid their use for children’s apps, the study found.
The researchers also said that nearly half the apps fail to always use standard security measures to transmit sensitive data over the Web, suggesting a breach of reasonable data security measures mandated by COPPA. Each of the 5,855 apps under review was installed more than 750,000 times, on average, according to the study.
Unfortunately for parents, there’s little consumers can do to protect themselves since the policies and business practices of app developers and ad tracking companies are often opaque, Egelman said.
The study also points to a breakdown of so-called self-regulation by app developers who claim to abide by child privacy laws, as well as by Google, which runs the Android platform, he said.