|This diagram is showing how severely metatherian mammals were affected when an asteroid hit Earth at the end of the Cretaceous, 66 million years ago. In North America, the number of metatherian species dropped from twenty species within the last million years of the Cretaceous Period, to just three species in the first million years of the Paleogene Period. – Dr Thomas Williamson|
The extinction of the dinosaurs 66 million years ago is thought to have paved the way for mammals to dominate, but a new study shows that many mammals died off alongside the dinosaurs.
Metatherian mammals–the extinct relatives of living marsupials (“mammals with pouches”, such as opossums) thrived in the shadow of the dinosaurs during the Cretaceous period. The new study, by an international team of experts on mammal evolution and mass extinctions, shows that these once-abundant mammals nearly followed the dinosaurs into oblivion.
|This is a fossil of a jawless fish. – Emma Randle, University of Manchester|
New research suggests our jawed ancestors weren’t responsible for the demise of their jawless cousins as had been assumed. Instead Dr Robert Sansom from The University of Manchester believes rising sea levels are more likely to blame. His research has been published in the journal Proceedings of the Royal Society B.
He says: “When our jawed vertebrate ancestors overtook their jawless relatives 400 million years ago, it seems that it might not have been through direct competition but instead the inability of our jawless cousins to adapt to changing environmental conditions.”
The Paleolithic diet, or caveman diet, a weight-loss craze in which people emulate the diet of plants and animals eaten by early humans during the Stone Age, gives modern calorie-counters great freedom because those ancestral diets likely differed substantially over time and space, according to researchers at Georgia State University and Kent State University.
|The concrete walls of Trajan’s Markets in Rome have stood the test of time and the elements for nearly 2,000 years. They have even survived a major earthquake in 1349. – Photo courtesy of Marie Jackson, Berkeley|
No visit to Rome is complete without a visit to the Pantheon, Trajan’s Markets, the Colosseum, or the other spectacular examples of ancient Roman concrete monuments that have stood the test of time and the elements for nearly two thousand years. A key discovery to understanding the longevity and endurance of Roman architectural concrete has been made by an international and interdisciplinary collaboration of researchers using beams of X-rays at the Advanced Light Source (ALS) of the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab).
A small stone container found by archaeologists a half-century ago has now been recognized as further evidence of a Viking or Medieval Norse presence in Arctic Canada during the centuries around 1000 A.D.