ScienceDaily: Fossils & Ruins News

Expanding the study of prehistoric permafrost thawing to North America, researchers found evidence in mineral deposits from caves in Canada that permafrost thawing took place as recently as 400,000 years ago, in temperatures not much warmer than today. But they did not find evidence the thawing caused the release of predicted levels of carbon dioxide stored in the frozen terrain.

Dating early human middens becomes uncertain beyond 50,000 years, when radiocarbon dating ceases to be useful. Uranium-series dating of marine shells and bone is uncertain by some 10% because of the structure of these materials. A team has now improved the method for a more stable discard: ostrich eggshells. The method extends the accuracy and precision of radiocarbon 10 times into the past, to about 500,000 years ago.

Parallel evolution is common, but do different animal populations evolve in similar ways and alter the same genes to adapt to similar environmental conditions? Researchers tested this in two U.S. populations of house mice. They found independent evolution of a heavier body and larger nests as Eastern and Western populations invaded northern habitats after introduction from Europe. Many of the same genes changed allele frequency along with the increase in body mass.

Research has shed new light on the impact of humans on Earth's biodiversity. The findings suggest that the rate of change in an ecosystem's plant-life increases significantly during the years following human settlement, with the most dramatic changes occurring in locations settled in the last 1500 years.

'Superhighways' used by a population of up to 6.5 million Indigenous Australians to navigate the continent tens of thousands of years ago have been revealed by new research using sophisticated modelling of past people and landscapes.