science news 10.7.2019

Today's selection of science news. Links are normally to press releases on EurekAlert (at the bottom end I may also add a couple of newspaper stories). I include quotes from the summary (using quotation marks) in cases where the title alone doesn't reveal what the story is about. My own thoughts appear without quotation marks, if I have any


earth

Semi-arid land in China has expanded in recent decades and probably continues to expand


evolution

Human pregnancy dependent on cells evolved in platypus-like animal 300 million years ago
"Platelet cells, which prevent mammals from bleeding non-stop, first evolved around 300 million years ago in an egg-laying animal similar to the modern duck-billed platypus, finds joint research by UCL and Yale University."


plants

Scientists decode DNA secrets of world's toughest bean
"scientists have decoded the genome of black-eyed peas, offering hope for feeding Earth's expanding population, especially as the climate changes. Understanding the genes responsible for the peas' drought and heat tolerance eventually could help make other crops tougher too."


zoology

Goats can distinguish emotions from the calls of other goats

Smells like love...to sea lampreys
"Some people are drawn to cologne; others are attracted to perfume. When it comes to sea lampreys, however, spermine smells like love. In new research led by Michigan State University and published in the current issue of PLoS Biology, spermine, an odorous compound found in male semen, proved to be a powerful aphrodisiac."



In new research led by Michigan State University and published in the current issue of PLoS Biology, spermine, an odorous compound found in male semen, proved to be a powerful aphrodisiac.
Credit: Courtesy of Michigan State University


humans

Gorillas found to live in 'complex' societies, suggesting deep roots of human social evolution


Elbows key for walkers' efficiency
"Why do walkers hold their arms straight and runners bend the arm at the elbow? A team of scientists at Harvard University campus have discovered that walking with a straight arm is much more efficient than holding it bent, but the jury is still out why runners bend their arms."
why don't they just put their arms behind their backs, they're more aerodynamic that way? I'd suspect it's to do with our evolutionary ancestors running on four legs, may have been kept to signal readiness for fight?