What’s the News: Infidelity among monogamous bird couples has always been something of a stumper for biologists. It’s easy enough to understand from the male’s perspective—the more he plays the field, the more offspring he has. But why do females cheat? True, she might get more genetic variety among her offspring, which could help them survive. But the benefits aren’t as clear, especially since she risks losing her mate.
To shed some light on the subject, scientists have charted the coupling of zebra finches, which are usually monogamous, and found that there’s a genetic reason some females engage in extracurricular activity: they get it from their fathers. And this supports a new take on the evolution of infidelity. Maybe it doesn’t have to be in the female’s interest to cheat—maybe it just has to be in her dad’s interest.
What’s the News: Mammals’ increased brain size may have come from long-ago natural selection for a better sense of smell, suggests a new study published today in Science. By reconstructing in 3D the skulls of two animals far back on the mammal family tree, the researchers saw that growth of smell-related brain regions accounted for much of the early increase in brain size as mammals developed.
What’s the News: Around 600 million years ago, Earth’s first multicellular moving animals evolved. Known as the Ediacaran fauna, these early slug- and worm-like creatures fed off microbial mats that covered the ocean floor. For years, scientists have debated how these animals kept themselves from suffocating because the ocean at the time is thought to have had less than half of its current oxygen levels. Looking at modern environments that are also oxygen-depleted, scientists have discovered that oxygen levels spike near biomats, plant-like bacteria that pump out oxygen as a waste product of photosynthesis. “We think that animals used the small but highly oxygenated zones as oases,” lead author Murray Gingras told Nature, giving the world’s first complex animals the kick-start they needed to evolve. “This is a really neat solution to an old problem,” Ediacaran researcher Jim Gehling told New Scientist. (more…)
What’s the News: The diminutive, unassuming Alice robot has helped a Swiss research team test a core tenet about the evolution of altruism, called Hamilton’s rule. The researchers’ new study shows that even simple robots operating with simple evolutionary rules can recreate evolution’s complex interplay of selfishness and selflessness.
What’s the News: It turns out that the strong-jawed, big-toothed human relative colloquially known as “Nutcracker man” may never have tasted a nut. In a finding that questions traditional ideas of early hominid diet, researchers discovered that Paranthropus boisei, a hominid living in east Africa between 2.3 and 1.2 million years ago, mostly fed on grasses and sedges. “Frankly, we didn’t expect to find the primate equivalent of a cow dangling from a remote twig of our family tree,” researcher Matt Sponheimer told MSNBC. (more…)
What’s the News: British scientists searching for signs of climate change in banded snail shells have completed one of the largest evolutionary studies ever, a massive survey across 15 European countries. Their research associates? More than 6,000 snail-hunting volunteers.
What’s the News: Researchers have unearthed the largest fossilized spider yet, announced in a study online today in Biology Letters. The fossil, a Jurassic Period ancestor of the modern orb-weaver spider, gives scientists a glimpse not only into the evolutionary history of orb-weaver spiders, but how these ancient arachnids might have impacted the evolution of insect species that could be snared in the webs.
What’s the News: The oldest recovered dinosaurs, including two-legged predators like Herrerasaurus, tromped around Argentina and Brazil some 230 million years ago. But exactly what happened after those beasts is a mystery: paleontologists have puzzled over an evolutionary gap in the fossil record between these early creatures and the more complex theropods, a suborder of bipedal dinosaurs—including Tyrannosaurus rex—that eventually comprised all dino carnivores. In the rocks of New Mexico’s Ghost Ranch, paleontologists have discovered the skull and vertebrae of a new dinosaur species that may fill this evolutionary gap. Dubbed Daemonosaurus chauliodus, this up-to-five-feet long, 205-million-year old predator has characteristics of both the first dinosaurs and the more advanced predators. As Hans-Dieter Sues, a paleontologist at the National Museum of Natural History in Washington, D.C., told National Geographic, the skull is unusual because “it has a … short snout and these monstrous front teeth. That’s a kind of skull structure for a predatory dinosaur that’s really unexpected for this early point in time.”
What’s the News: Test-tube evolution just went viral: a new study shows how to use viruses’ knack for natural selection to create tailored proteins. Researchers at Harvard say their new technique is a hundred times faster than the usual methods, churning through 200 generations of proteins in 8 days, and, crucially, requires no attention from researchers after it’s set up: a crock pot for evolution. Though a godsend primarily for researchers, in the future it could accelerate the growth of customized proteins for new drugs.
Scientists have harnessed the power of viruses in a method for evolving customized proteins.
What’s the News: The reproductive life of a cuckoo is both easy—it lays its eggs in others birds’ nests, and lets them feed the young—and difficult: cuckoos are involved in an “evolutionary arms race” with other birds, finds a new study. Even as cuckoos improve their counterfeiting skills—producing eggs that look more like others birds’—the host birds get better and better at identifying the forged eggs.
How the Heck:
Knowing that birds have four types of color-sensitive cone cells in their eyes, allowing them to see ultraviolet wavelengths, researchers used a spectroscope to measure the amount of light reflected from hundreds of cuckoo and host-bird eggs. They then fed this data into models to produce images showing how birds see the different types of eggs.
They discovered that while cuckoo and redstart eggs have a high degree of color overlap, cuckoo eggs targeted for dunnock nests did not.
Here’s the kicker: Redstarts and dunnocks don’t spot forgeries equally. Redstarts are more discerning of foreign eggs and readily kick out cuckoo forgeries, while the dumb dunnocks accept even the most mismatched eggs. So these findings suggest that cuckoos targeting redstarts evolved the ability to create better forgeries because the redstart has such a good eye. With dunnocks, that evolutionary force wasn’t at play because the birds are so accepting of forgeries; why bother?
What’s the Context:
What sets this research apart from previous work is how the researchers used UV-sensing equipment to mimic bird vision. (Past research relied merely on human inspection.)
The Future Holds: Scientists still aren’t sure why some hosts, like the dunnock, are so accepting of cuckoo eggs. Some scientists argue that this is because the risk in mistakenly rejecting a real egg outweighs the cost of raising a cuckoo egg. The jury’s still out.
Reference: “AVIAN VISION AND THE EVOLUTION OF EGG COLOR MIMICRY IN THE COMMON CUCKOO” Mary Caswell Stoddard and Martin Stevens. DOI: 10.1111/j.1558-5646.2011.01262.x
What happens when evolutionary biology disagrees with archeology? If you’re thinking “scientific headache,” you’re right. New research suggests that Europeans first regularly used fire no earlier than 400,000 years ago—an assertion that, if true, leaves evolutionary anthropologists in a lurch because this date isn’t linked to the substantial physiological changes we’d expect with the advent of cooked food.
The Controversy
The majority of archeologists think that early humans’ control of fire is tied to their migration out of Africa. After all, how else would the first Europeans cope with the freezing winters?
Based on archeological evidence, we know that early humans first arrived in southern Europe over a million years ago, and—based on the Happisburgh site —reached England around 800,000 years ago. So the problem with the new 400,000 year-old date is that it means that hominids suffered through hundreds of thousands of years of cold winter unaided by fire. And according to evolutionary biologists, this new date clashes with the idea that cooked food aided the evolutionary enlargement of the human brain.
At first glance, biologists slapping motion capture gear onto kangaroos sounds like a scientific foray into the 3-D-movie craze. But James Cameron can rest assured: The scientists are merely performing their day jobs, studying kangaroos—and using a nifty new camera to do it.
As kangaroos mosey along at low speeds, they walk, using their tail as a fifth limb. But as they speed up, they slip into their signature bounce. The mystery for scientists is why such large animals—some being over six feet tall—are so darn springy, and as Alexis Wiktorowicz-Conroy, a researcher at the Royal Veterinary College, told the BBC, “We can’t really explain … why their bones don’t break at high speeds.” (more…)
Unwelcome melt: The results are in for a 20-year study of Antarctica and Greenland ice melt, and though you shouldn’t grab your swim trunks yet, the results show that ice sheets have been melting at an accelerated pace for the past 20 years. “What is surprising,” Eric Rignot from Nasa’s Jet Propulsion Laboratory (JPL) in Pasadena, California, told the BBC, is that ice melt will soon be the single biggest driver of sea level rise.
But don’t take these dripping glaciers as a reason to sit on your hands: A new report says that climatologists aren’t factoring in soot in the climate debate—and that merely reducing the output from cooking fires and industry could cut global warming by 0.5C. Food for thought (oy) the next time you barbecue.
Lessons from a tree: Engineers have crafted a self-repairing plastic based on the natural self-repairing traits of rubber trees—a discovery that could save energy (and the planet) by extending the lifespan of many consumer products.
The Hudson River has been one of the most polluted in America, but because of that pollution, it’s now the site of evolution happening at a breakneck pace.
The furiously evolving species is the bottom-feeding Atlantic tomcod, which lives in areas of the Hudson that were contaminated by PCBs through much of the 20th century.
PCBs, or polychlorinated biphenyls, were first introduced in 1929 and were used in hundreds of industrial and commercial applications, mostly as electrical insulators. They were banned 50 years later, but they don’t simply degrade. Partly because of PCB contamination, a 200-mile stretch of the Hudson River is the nation’s largest Superfund site. [National Geographic]
Despite swimming in PCB-polluted waters and accumulating the chemicals in their systems, the tomcods are alive and well in the river. In a study in Science this week, Isaac Wirgin and colleagues show that this is because in the span of just a few dozen generations, the fish have evolved a resistance to PCBs.
Ask a group of snake researchers whether our modern snakes evolved from land-loving or ocean-loving lizards, and you’re likely to start a heated argument. But the days of snake-origin squabbles may be coming to a close–researchers have created the first 3-D images of snake fossils and have discovered that their legs are more akin to the legs of land-dwelling lizards than they are to the ocean-dwelling kind.
The researchers studied a 95-million-year-old fossilized snake called Eupodophis descouensi that was found in present-day Lebanon. Published in the Journal of Vertebrate Paleontology, the scientists used a novel 3-D imaging technique called synchrotron-radiation computed laminography:
“Synchrotrons are enormous machines and allow us to see microscopic details in fossils invisible to any other techniques without damage to these invaluable specimens,” said co-author Paul Tafforeau from the European Synchrotron Radiation Facility. [Discovery News]
80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles on the day's most compelling topics.
80beats is written by Veronique Greenwood and Valerie Ross. This team darts through each day's science news faster than the ruby-throated hummingbird that beats its wings 80 times per second. Send ideas, tips, suggestions, and complaints to [azeeberg at discovermagazine dot com].
What’s the News: Mammals’ increased brain size may have come from long-ago natural selection for a better sense of smell, suggests a new 
What’s the News: Around 600 million years ago, Earth’s first multicellular moving animals evolved. Known as the 
Alice robots at work.
Nephila jurassica, with a 5mm scale bar
What’s the News: The oldest recovered dinosaurs, including two-legged predators like 
What’s the News: The reproductive life of a cuckoo is both easy—it lays its eggs in others birds’ nests, and lets them feed the young—and difficult: cuckoos are involved in an “
What happens when evolutionary biology disagrees with archeology? If you’re thinking “scientific headache,” you’re right. New research suggests that Europeans first regularly used fire no earlier than 400,000 years ago—an assertion that, if true, leaves evolutionary anthropologists in a lurch because this date isn’t linked to the substantial physiological changes we’d expect with the advent of cooked food.
