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Zoologger: The first solar-powered vertebrate
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Ernie Janes/naturepl.com
HOW do you spot a fit partridge? Check out the fractals round its neck. Fractal geometry is used when a pattern is too complex to be described by Euclidean geometry. It has been applied to coastlines, plant structures and animals’ foraging patterns. Lorenzo Pérez-Rodríguez at the National Museum of Natural Sciences in Madrid, Spain, and colleagues wanted to see if it could also be helpful when analysing the complex plumage patterns of birds. Using images fed into software, the team found that red-legged partridges (see picture) with a more gradual transition between the plain and spotted areas of their bib have a higher fractal dimension (FD) – a measure of a pattern’s complexity. To see if this was linked to the bird’s fitness, they compared the bibs of 68 birds of both sexes, half of which were on a restricted diet. After six months, the bibs of undernourished birds had a lower FD than before their food was reduced. Low FD also predicted poorer immune responsiveness. Pérez-Rodríguez thinks that a fractal-rich bib could be used to advertise the health of the bird to potential mates. “Birds have quite a different visual system to ours,” says Thanh-Lan Gluckman at the University of Cambridge, so the work could also help us understand what one bird sees in another.
Solar-powered salamander hooks up with green algae ANIMALS are weird. They ignore the abundant source of energy above their heads – the sun – and instead invest in cumbersome kit for eating and digesting food. Not so the spotted salamander (Ambystoma maculatum): its embryos use algae as batteries. We have long known that the embryos live in symbiosis with single-celled algae, Oophila amblystomatis. The algae colonise the eggs, receiving organic waste as food in exchange for oxygen, which they generate by photosynthesis. Then in 2011,
researchers found the algae not just inside the eggs, but also inside the embryos’ cells. To see if the embryos get more than oxygen from the algae, Erin Graham of Temple University in Philadelphia, Pennsylvania, and colleagues incubated eggs in water containing radioactive carbon-14. The algae take up carbon in the form of carbon dioxide, producing oxygen and radioactive glucose. The team found that the embryos became mildly radioactive unless kept in dark
conditions, something that could only be explained if the embryos were using the glucose. In other words, the algae were acting as internal power stations, generating fuel for the embryos (Journal of Experimental Biology, doi.org/j8q). Salamander embryos deprived of algae struggle. “Their survival rate is much lower and their growth is slowed,” says Graham. Other vertebrates may well have a similar relationship with algae, she says: “Anything that lays its eggs in water would be a good candidate.” Martin Parr/Magnum Photos
Look at my blingy fractal necklace
Brightest light from black hole’s spit GLOBS of plasma spat out by black holes can trigger the brightest flashes of light in the universe. Gamma-ray bursts are highenergy flares that mostly originate billions of light years away, making it hard to see how they are created. In November 2011, NASA’s Fermi satellite saw a gamma-ray burst coming from the galaxy 4C +71.07, which sits about 10.5 billion light years away. The galaxy was also being watched by the Very Long Baseline Array, a radio telescope network that can see small features at a distance. The supermassive black hole at the galaxy’s centre is feeding on surrounding matter, causing it to fire high-speed jets of particles. The radio array showed that, around the same time as the flare, the black hole spat out a knot of plasma that travelled up the jet at near the speed of light. Electrons in the knot probably collided with and energised light from a slower-moving part of the jet, producing the gamma rays, says Alan Marscher of Boston University, who presented the work at a recent astronomy meeting in California. It’s still a mystery, though, what made the black hole erupt.
Back off my cake, it defines me DOGS famously love a bone, but a taste for starch may have helped to turn their ancestors from wolves into pooches. The first comparison of the full genomes of wolves and dogs has found 36 segments that clearly differ. Besides differences in genes linked to brain development, Erik Axelsson of Uppsala University in Sweden and colleagues found three genes in dogs that are vital for digestion and extend their ancestral carnivorous diet to include starch (Nature, DOI: 10.1038/nature11837).
A gene for the enzyme that splits starch into simpler sugars has replicated itself in the dog genome, and become more efficient – a sure sign that it is in demand. Although the team has yet to date the emergence of these genes, Axelsson suggests one possibility is that it coincided with the dawn of agriculture, as settlements filled with heaps of starchy waste. “Wolves were probably attracted, but only the ones that evolved the ability to digest the starch waste kept coming back,” he says.
26 January 2013 | NewScientist | 17
Ernie Janes/naturepl.com
HOW do you spot a fit partridge? Check out the fractals round its neck. Fractal geometry is used when a pattern is too complex to be described by Euclidean geometry. It has been applied to coastlines, plant structures and animals’ foraging patterns. Lorenzo Pérez-Rodríguez at the National Museum of Natural Sciences in Madrid, Spain, and colleagues wanted to see if it could also be helpful when analysing the complex plumage patterns of birds. Using images fed into software, the team found that red-legged partridges (see picture) with a more gradual transition between the plain and spotted areas of their bib have a higher fractal dimension (FD) – a measure of a pattern’s complexity. To see if this was linked to the bird’s fitness, they compared the bibs of 68 birds of both sexes, half of which were on a restricted diet. After six months, the bibs of undernourished birds had a lower FD than before their food was reduced. Low FD also predicted poorer immune responsiveness. Pérez-Rodríguez thinks that a fractal-rich bib could be used to advertise the health of the bird to potential mates. “Birds have quite a different visual system to ours,” says Thanh-Lan Gluckman at the University of Cambridge, so the work could also help us understand what one bird sees in another.
Solar-powered salamander hooks up with green algae ANIMALS are weird. They ignore the abundant source of energy above their heads – the sun – and instead invest in cumbersome kit for eating and digesting food. Not so the spotted salamander (Ambystoma maculatum): its embryos use algae as batteries. We have long known that the embryos live in symbiosis with single-celled algae, Oophila amblystomatis. The algae colonise the eggs, receiving organic waste as food in exchange for oxygen, which they generate by photosynthesis. Then in 2011,
researchers found the algae not just inside the eggs, but also inside the embryos’ cells. To see if the embryos get more than oxygen from the algae, Erin Graham of Temple University in Philadelphia, Pennsylvania, and colleagues incubated eggs in water containing radioactive carbon-14. The algae take up carbon in the form of carbon dioxide, producing oxygen and radioactive glucose. The team found that the embryos became mildly radioactive unless kept in dark
conditions, something that could only be explained if the embryos were using the glucose. In other words, the algae were acting as internal power stations, generating fuel for the embryos (Journal of Experimental Biology, doi.org/j8q). Salamander embryos deprived of algae struggle. “Their survival rate is much lower and their growth is slowed,” says Graham. Other vertebrates may well have a similar relationship with algae, she says: “Anything that lays its eggs in water would be a good candidate.” Martin Parr/Magnum Photos
Look at my blingy fractal necklace
Brightest light from black hole’s spit GLOBS of plasma spat out by black holes can trigger the brightest flashes of light in the universe. Gamma-ray bursts are highenergy flares that mostly originate billions of light years away, making it hard to see how they are created. In November 2011, NASA’s Fermi satellite saw a gamma-ray burst coming from the galaxy 4C +71.07, which sits about 10.5 billion light years away. The galaxy was also being watched by the Very Long Baseline Array, a radio telescope network that can see small features at a distance. The supermassive black hole at the galaxy’s centre is feeding on surrounding matter, causing it to fire high-speed jets of particles. The radio array showed that, around the same time as the flare, the black hole spat out a knot of plasma that travelled up the jet at near the speed of light. Electrons in the knot probably collided with and energised light from a slower-moving part of the jet, producing the gamma rays, says Alan Marscher of Boston University, who presented the work at a recent astronomy meeting in California. It’s still a mystery, though, what made the black hole erupt.
Back off my cake, it defines me DOGS famously love a bone, but a taste for starch may have helped to turn their ancestors from wolves into pooches. The first comparison of the full genomes of wolves and dogs has found 36 segments that clearly differ. Besides differences in genes linked to brain development, Erik Axelsson of Uppsala University in Sweden and colleagues found three genes in dogs that are vital for digestion and extend their ancestral carnivorous diet to include starch (Nature, DOI: 10.1038/nature11837).
A gene for the enzyme that splits starch into simpler sugars has replicated itself in the dog genome, and become more efficient – a sure sign that it is in demand. Although the team has yet to date the emergence of these genes, Axelsson suggests one possibility is that it coincided with the dawn of agriculture, as settlements filled with heaps of starchy waste. “Wolves were probably attracted, but only the ones that evolved the ability to digest the starch waste kept coming back,” he says.
26 January 2013 | NewScientist | 17