Enlarge (credit: Carnegie Mellon University )

Until now, when scientists and engineers have developed soft robots inspired by organisms, they’ve focused on modern-day living examples. For instance, we previously reported on soft robot applications that mimicked squid , grasshoppers, and cheetahs . For the first time, however, a team of researchers has now combined the principles of soft robotics and paleontology to build a soft-robot version of pleurocystitid, an ancient sea creature that existed 450 million years ago.

Pleurocystitids are related to modern-day echinoderms like starfish and brittle stars. The organism holds great significance in evolution because it is believed to be the first echinoderm that was capable of moving: It employed a muscular stem to move on the sea bed. But, due to a lack of fossil evidence, scientists never clearly understood how the organism actually used the stem to move underwater. “Although its life habits and posture are reasonably well understood, the mechanisms that control the movement of its stem are highly controversial,” authors of a previously published study focusing on the echinoderm stem note .

The newly developed soft-robot replica (also called the “Rhombot”) of a pleurocystitid has allowed researchers to decode the organism’s movement and various other mysteries linked to the evolution of echinoderms. In their study, they also claim that the replica will serve as the foundation of paleobionics, a relatively new field that uses soft robotics and fossil evidence to explore the biomechanical differences among life forms.

Enlarge / In the case of Great Barrier Reef green turtles, rising temperatures have been linked to changing sex-determination, with an increasing number of new hatchlings born female. (credit: Jonas Gratzer/LightRocket via Getty Images)

Humans are driving migratory animals—sea turtles, chimpanzees, lions and penguins, among dozens of other species—towards extinction, according to the most comprehensive assessment of migratory species ever carried out.

The State of the World’s Migratory Species , a first of its kind report compiled by conservation scientists under the auspices of the U.N. Environment Programme’s World Conservation Monitoring Centre, found population decline, a precursor to extinction, in nearly half of the roughly 1,200 species listed under the Convention on Migratory Species (CMS), a 1979 treaty aimed at conserving species that move across international borders.

The report’s findings dovetail with those of another authoritative U.N. assessment, the 2019 Global Assessment Report on Biodiversity and Ecosystem Services , that found around 1 million of Earth’s 8 million species are at risk of extinction due to human activity. Since the 1970s, global biodiversity, the variation of life on Earth, has declined by a whopping 70 percent.

Enlarge (credit: MARK GARLICK/SCIENCE PHOTO LIBRARY )

Classic whodunit mysteries work because just about every character ends up being a murder suspect. The demise of non-avian dinosaurs is a lot like that. The Chicxulub impact and its aftereffects created a huge range of potentially lethal suspects. Whodunit? A giant fireball and massive tsunamis? Wild swings in the climate? Global wildfires? A blackened sky that shut down photosynthesis? All of the above?

Modeling these impacts, combined with data on the pattern of extinctions, has led to various opinions on what proved decisive regarding the extermination of so many species. In the latest look at the end-Cretaceous extinction, a team of scientists largely based in Brussels has revisited deposits laid down in the aftermath of the impact and found that much of the debris came from fine dust. When that dust is plugged into climate models, global temperatures plunge by as much as 25° C, and photosynthesis shuts down for almost two years.

Dust to dust

There was a lot going on in the atmosphere in the years after the impact. Debris thrown up by the impact would have re-entered Earth's atmosphere, burning up into fine rocky and sulfur-rich particles in the process. The heat generated by this process would have set off massive wildfires, adding a lot of soot to the mix. And all of that was churned up with the debris from the impact that stayed within the atmosphere.

Enlarge / The Nicobar pigeon, the dodo's closest living relative, is quite a bit smaller and capable of flight. (credit: Samuel Hambly / EyeEm )

Colossal is a company that got its start with a splashy announcement about plans to do something that many scientists consider impossible with current technology, all in the service of creating a product with no clear market potential: the woolly mammoth. Since that time, the company has settled into a potentially viable business model and set its sights on a species where the biology is far more favorable: the thylacine, a marsupial predator that went extinct in the early 1900s.

Today, the company is announcing a third de-extinction target and its return to the realm of awkward reproductive biology that will force the project to clear many technical hurdles: It hopes to bring back the dodo.

A shifting symbol

The dodo was a large (up to 1 meter tall), flightless bird that evolved on the island of Mauritius in the Indian Ocean. As European sailors reached the islands, it quickly became a source of food for them and the invasive species that accompanied them. It went extinct within a century of the first descriptions reaching Europe.

Enlarge / Alpine chipmunks collected by pioneering naturalist Joseph Grinnell in the early 20th century are still preserved at the Museum of Vertebrate Zoology at the University of California, Berkeley. Recently, geneticists used DNA extracted from them to trace how the chipmunks have evolved. Museum collections like this can give researchers at time machine to the past. ( CC BY-NC 2.0 ) (credit: KQED Quest )

Natural history’s golden age, when Charles Darwin and like-minded scientists pondered connections between creatures and their environments, largely revolved around collecting stuff. Explorers fanned out across the world and picked up as many plants and animals as they could, drying them or stuffing them or storing them in alcohol in small glass jars. They carried them home to grand museums where the public might get a peek at them and be amazed.

These venerable collections can seem like relics today—musty storehouses, shrines to imperial plunder. But with billions of samples catalogued among them, museum collections are a treasure for modern evolutionary biologists studying DNA, RNA, proteins and other biomolecules. Sampling decades- or even centuries-old tissues allows scientists to capture snippets of genetic code from plants and animals—including extinct ones—and track molecular changes that took place long before biologists even understood what DNA was. Younger specimens are valuable too, providing a large sampling to help scientists compare traits within a species or between related ones.

All of this makes working with museum samples a tantalizing prospect for researchers, says Harvard evolutionary geneticist Daren Card, who has sequenced specimens from Australian museums for his own work on limb development in reptiles. Museum genomics is delivering crucial insights into evolutionary history, the effects of climate change and more, Card and colleagues write in the 2021 Annual Review of Genetics . Knowable spoke with Card about some of these projects—and some challenges the field faces.

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