Enlarge / Grasshoppers, beware! Robopteryx is here to flush you from your hiding place. (credit: Jinseok Park, Piotr Jablonski et al., 2024)

Scientists in South Korea built a robotic dinosaur and used it to startle grasshoppers to learn more about why dinosaurs evolved feathers, according to a recent paper published in the journal Scientific Reports. The results suggest that certain dinosaurs may have employed a hunting strategy in which they flapped their proto-wings to flush out prey, and this behavior may have led to the evolution of larger and stiffer feathers.

As reported previously , feathers are the defining feature of birds, but that wasn't always the case. For millions of years, various species of dinosaurs sported feathers, some of which have left behind fossilized impressions. For the most part, the feathers we've found have been attached to smaller dinosaurs, many of them along the lineage that gave rise to birds—although in 2012, scientists discovered three nearly complete skeletons of a "gigantic" feathered dinosaur species, Yutyrannus huali, related to the ancestors of Tyrannosaurus Rex .

Various types of dino-feathers have been found in the fossil record over the last 30 years, such as so-called pennaceous feathers (present in most modern birds). These were found on distal forelimbs of certain species like Caudipteryx , serving as proto-wings that were too small to use for flight, as well as around the tip of the tail as plumage. Paleontologists remain unsure of the function of pennaceous feathers—what use could there be for half a wing? A broad range of hypotheses have been proposed: foraging or hunting, pouncing or immobilizing prey, brooding, gliding, or wing-assisted incline running, among others.

Enlarge (credit: Rodolfo Parulan Jr. )

Genetic mutations are essential for innovation and evolution, yet too many—or the wrong ones—can be fatal. So researchers at Cambridge established a synthetic “orthogonal” DNA replication system in E. coli that they can use as a risk-free way to generate and study such mutations. It is orthogonal because it is completely separate from the system that E. coli uses to copy its actual genome, which contains the genes E. coli needs to survive.

The genes in the orthogonal system are copied with an extraordinarily error-prone DNA replication enzyme, which spurs rapid evolution by generating many random mutations. This goes on while E. coli ’s genes are replicated by its normal high-fidelity DNA copying enzyme. The two enzymes work alongside each other, each doing their own thing but not interfering with the other’s genes.

Engineering rapid mutation

Such a cool idea, right? The scientists stole it from nature. Yeast already has a system like this, with a set of genes copied by a dedicated enzyme that doesn’t replicate the rest of the genome. But E. coli is much easier to work with than yeast, and its population can double in 20 minutes, so you can get a lot of rounds of replication and evolution done fast.

Enlarge / The Golgi apparatus, shown here in light green, may have been involved in building internal structures in cells. (credit: ARTUR PLAWGO / SCIENCE PHOTO LIBRARY)

Before Neanderthals and Denisovans, before vaguely humanoid primates, proto-mammals, or fish that crawled out of the ocean to become the first terrestrial animals, our earliest ancestors were microbes.

More complex organisms like ourselves descend from eukaryotes , which have a nuclear membrane around their DNA (as opposed to prokaryotes , which don’t). Eukaryotes were thought to have evolved a few billion years ago, during the late Palaeoproterozoic period, and started diversifying by around 800 million years ago. Their diversification was not well understood. Now, a team of researchers led by UC Santa Barbara paleontologist Leigh Ann Riedman discovered eukaryote microfossils that are 1.64 billion years old, yet had already diversified and had surprisingly sophisticated features.

“High levels of eukaryotic species richness and morphological disparity suggest that although late Palaeoproterozoic [fossils] preserve our oldest record of eukaryotes, the eukaryotic clade has a much deeper history,” Riedman and her team said in a study recently published in Papers in Paleontology.

Enlarge / An example of a Littorina species, the common periwinkle. (credit: Bjoern Wylezich )

The version of evolution proposed by Charles Darwin focused on slow, incremental changes that only gradually build into the sort of differences that separate species. But that doesn't rule out the potential for sudden, dramatic changes. Indeed, some differences make it difficult to understand what a transitional state would look like, suggesting that a major leap might be needed.

A new study looks at one major transition: the shift from egg-laying to live births in a set of related snail species. By sequencing the genomes of multiple snails, the researchers identified the changes in DNA that are associated with egg-laying. It turns out that a large number of genes are associated with the change despite its dramatic nature.

Giving up eggs

The snails in question are in a genus called Littorina , which are largely distributed around the North Atlantic. Many of these species lay eggs, but a number of them have transitioned to live births. In these species, an organ that coats eggs with a protein-rich jelly in other species instead acts as an incubator, allowing eggs to develop until young snails can crawl out of their parent's shells. This is thought to be an advantage for animals that would otherwise have to lay eggs in environments that aren't favorable for their survival.

Enlarge / A large family can come with some unfortunate downsides (in addition to that weird cousin). (credit: Oliver Rossi )

Analysis of genomic and behavioral data from the vast UK Biobank finally demonstrates that genes that promote reproductive behaviors come with the ultimate price.

Aging stinks. You get marks on your skin, you’re slower, you forget stuff, and everything hurts. Your joints crack and pop. Evolution has achieved so many remarkable things; how is it possible that we still have to put up with growing old?

The antagonistic pleiotropy hypothesis states that your body falls apart when you’re old to pay the cost of being reproductively fit when you’re young. If the same gene has different effects (called pleiotropy) at different times of life—if it enhances your chances of reproduction when you’re young but is deleterious somehow once you get older—that gene will still undergo positive selection and remain in the population because reproduction is that important.

Enlarge (credit: Henry Sharpe / AMNH)

In 2015, Deborah Shepherd returned to the site where she and other volunteers had worked on a public fossil dig with family members. That’s when she saw it: a fossil lying there, exposed on the surface. Most people would not have recognized it for what it was: It wasn’t a skull, a leg bone, or even a partial jaw. It was just a chunk of bone.

Shepherd immediately notified a park ranger. That ranger then notified the North Dakota Department of Mineral Resources. Her actions ultimately led to the discovery of what scientists say is not only a new species, but an entirely new genus of mosasaur, a giant marine predator from Late Cretaceous seas. Bite marks preserved on the fossil also suggest that it met its end at the hands—or rather teeth—of another mosasaur.

Meet Jorgie the mosasaur

The new mosasaur was described Monday in the Bulletin of the American Museum of Natural History. Jǫrmungandr walhallaensis , or "Jorgie" for short, is the name suggested by co-author Clint Boyd, and it’s steeped in Norse mythology. Jǫrmungandr is the name of a sea serpent who circles the world with its body, clasping its tail in its jaws.

Enlarge / Atlantic puffin, Spitsbergen, Svalbard Islands, Norway. (credit: Sergio Pitamitz/VWPics/Universal Images Group via Getty Images)

The brisk increase in warming rates in the Arctic is bringing rapid shifts in range for plants and animals across the region’s tree of life. Researchers say those changes can lead species that normally wouldn’t encounter each other to interbreed, creating new hybrid populations.

Now, scientists have presented the first evidence of large-scale hybridization that appears to have been driven by climate change. In a paper published this month in the journal Science Advances, researchers report that a hybrid Atlantic puffin population on the remote Norwegian island of Bjornoya seems to have emerged in a period coinciding with the onset of a faster pace of global warming.

The hybrid puffins likely arose from the breeding between two subspecies within the past 100 or so years, coinciding with the onset of the 20th-century warming pattern, the study concludes. Strikingly, the hybridization occurred after a subspecies migrated southward, not poleward toward cooler temperatures, as might have been expected, a finding that highlights the complexity of the changes underway in the Arctic ecosystem.

Enlarge / Fish-eating kingfishers execute plunging dives into the water to capture prey, yet never seem to get concussed. (credit: Richard Towell)

There are many different species of kingfisher, and those that eat fish hunt by repeatedly diving head-first into the water when they spot tasty prey without suffering brain injuries like concussions. It turns out that diving kingfishers have several modified genes associated with diet and brain structure, according to a new paper published in the journal Communications Biology—notably mutations in genes related to the tau proteins that help stabilize neuron structure, although they can be harmful if too many build up.

“I learned a lot about tau proteins when I was the concussion manager of my son’s hockey team,” said co-author Shannon Hackett , associate curator of birds at the Field Museum. “I started to wonder, why don’t kingfishers die because their brains turn to mush? There’s gotta be something they're doing that protects them from the negative influences of repeatedly landing on their heads on the water’s surface.”

It's not the first time scientists have pondered this question, not just for kingfishers, but for other birds like gannets and woodpeckers . For instance, physicists at Virginia Tech studied diving gannets back in 2014 (publishing their conclusions in 2016 ), which fold their wings back as they dive, hitting the water with their whole body to snag underwater prey. From a physics standpoint, we're talking about an elastic body hitting the surface of water as fast as 55 MPH. The stress of moving from the medium of air to the much denser medium of water exerts a huge force on the bird's body, with an impact akin to tornadoes hitting the water. Yet despite the stress on their bodies, gannets (like the kingfisher) manage the feat again and again without injury, especially concussions.