MI weekly selection #50
Strawberry poison frogs pass on chemical defense to offspring
Strawberry poison frogs provide chemical defenses to their tadpoles by feeding them eggs spiked with alkaloids. Researchers measured alkaloid content in the frogs during different stages of development, separating them into two groups — one in which tadpoles were reared and fed by their mothers and the other in which the scientists undertook the care and feeding. The results showed that the tadpoles reared by their mothers contained alkaloids in most stages as opposed to those raised by researchers.
National Geographic / Weird & Wild
Mystery around Denisovans grows as genome study finds unidentified DNA
The mystery surrounding the hominin species known as the Denisovans has deepened after scientists found bits of DNA in the Denisovan genome that seems to be from another group. Little is known about the Denisovans since so little fossil evidence has been found, but geneticists have been able to sequence their genome quite accurately. The latest find, presented by Harvard Medical School’s David Reich at a Royal Society meeting about ancient DNA, suggests that Denisovans interbred with an as-yet unidentified species.
3D printer replicates dinosaur fossil
Using a CT scanner and a 3D printer, researchers have copied a dinosaur fossil wrapped in a protective layer of plaster without having to break open the covering, paving the way for scientists to study extremely fragile objects, according to a report in Radiology.
Mars likely had more volcanic activity than once thought
Mars may have been more volcanically active than previously thought, according to two separate studies published in Nature Geoscience. European Southern Observatory researchers found eight unique locations on Mars that held significant deposits of feldspar minerals, commonly found in only the upper continental crust on Earth and the highlands of the moon, where feldspar minerals form on the surface of magma lakes. Georgia Institute of Technology scientists reported similar findings, suggesting that Mars once had large oceans of magma.
Octopus arms seem to have minds of their own
Octopuses can turn their bodies independent of their direction of movement while continuing to move in a straight line, according to research presented recently at the Society for Neuroscience annual meeting in San Diego. Researchers used a tank hooked up with mirrors and video cameras to help them deconstruct the octopuses’ movements. The brain sends out commands, but lets the limbs’ neurons work out the movement details, the research suggests.