Extinction changes rules of body size evolution

A trilobite fossil from the Ordovician period, which lasted from about 485 to 443 million years ago. A new analysis of marine fossils from most of the past half-billion years shows the usual rules of body size evolution change during mass extinctions and their recoveries.
(Image credit: Smithsonian)

Scientists at Stanford University have discovered a surprising pattern in how life reemerges from cataclysm. Research published in Proceedings of the Royal Society B shows the usual rules of body size evolution change not only during mass extinction, but also during subsequent recovery.

Since the 1980s, evolutionary biologists have debated whether mass extinctions and the recoveries that follow them intensify the selection criteria of normal times – or fundamentally shift the set of traits that mark groups of species for destruction. The new study finds evidence for the latter in a sweeping analysis of marine fossils from most of the past half-billion years.

Whether and how evolutionary dynamics shift in the wake of global annihilation has “profound implications not only for understanding the origins of the modern biosphere but also for predicting the consequences of the current biodiversity crisis,” the authors write.

“Ultimately, we want to be able to look at the fossil record and use it to predict what will go extinct, and more importantly, what comes back,” said lead author Pedro Monarrez, a postdoctoral scholar in Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). “When we look closely at 485 million years of extinctions and recoveries in the world’s oceans, there does appear to be a pattern in what comes back based on body size in some groups.”

Birds learn to avoid plants that host dangerous insects

Cinnabar larvae feeding on ragwort
Credit: Callum McLellan

Young birds that eat insects with conspicuous warning coloration to advertise their toxicity to would-be predators quickly learn to avoid other prey that carry the same markings. Developing on this understanding, a University of Bristol team have shown for the very first time that birds don’t just learn the colors of dangerous prey, they can also learn the appearance of the plants such insects live on.

To do this, the scientists exposed artificial cinnabar caterpillars, characterized by bright yellow and black stripes, and non-signaling fake caterpillar targets to wild avian predation by presenting them on ragwort and a non-toxic plant - bramble, which is not a natural host of the cinnabar. Both target types survived better on ragwort compared to bramble when experienced predators were abundant in the population.

They were also interested in whether birds use the bright yellow flowers of ragwort as a cue for

An adult cinnabar moth on a ragwort stem
Credit: Callum McLellan

avoidance. They tested this by removing spikes of flowers from the ragwort and pinning them onto bramble, then recording target survival on either plant. In this second experiment, only the non-signaling targets survived better on plants with ragwort flowers, compared to the same plant type without the flowers. The survival of the cinnabar-like target was equal across all plant treatments

Lead author Callum McLellan, a graduate student at the School of Biological Sciences, said “Cinnabar caterpillars have this really recognizable, stripy yellow and black appearance. They also only live and feed on ragwort, which itself has distinctive yellow flowers. We have shown that birds learn that the ragwort flowers are a cue for danger, so can avoid going anywhere near toxic prey. It’s more efficient to avoid the whole plant than make decisions about individual caterpillars.”

Co-author Prof Nick Scott-Samuel of the School of Psychological Science, said “Our findings suggest that insect herbivores that specialize on easily recognizable host plants gain enhanced protection from predation, independent of their warning signal alone.”

Ragwort Credit: Callum McLellan

Prof Innes Cuthill, who conceived the study, added “Interestingly, any camouflaged caterpillars living on the same plant also benefit from birds’ learnt wariness of ragwort, despite being perfectly good to eat.

“Our results provide the opening to a brand-new discussion on how toxicity initially evolved in insect prey, and the conditions under which warning coloration is, or is not, favored.”

Paper:
‘Birds learn to avoid aposematic prey by using the appearance of host plants’ in Current Biology by Callum F. McLellan, Nicholas E. Scott-Samueland Innes C. Cuthill

Source/Credit: University of Bristol

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The Climate-Driven Mass Extinction No One Had Seen

 

Fossils of the key groups used to unveil the Eocene-Oligocene extinction in Africa with primates on the left, the carnivorous hyaenodont, upper right, rodent, lower right. These fossils are from the Fayum Depression in Egypt. (Credit: Matt Borths)

Sixty-three percent. That’s the proportion of mammal species that vanished from Africa and the Arabian Peninsula around 30 million years ago, after Earth’s climate shifted from swampy to icy. But we are only finding out about it now.

Compiling decades of work, a new study published this week in the journal Communications Biology reports on a previously undocumented extinction event that followed the transition between the geological periods called the Eocene and Oligocene.

That time period was marked by dramatic climate change. In a reverse image of what is happening today, the Earth grew cooler, ice sheets expanded, sea levels dropped, forests started changing to grasslands, and carbon dioxide became scarce. Nearly two-thirds of the species known in Europe and Asia at that time went extinct.

Crayfish and carp among invasive species pushing lakes towards ecosystem collapse

Asian silver carp

Human activity and climate change are causing invasive non-native species to spread rapidly across the globe. Researchers have found that certain invasive species can push lake ecosystems beyond a critical ‘tipping point’, causing a sudden shift from healthy to degraded conditions that is difficult to reverse.

Invasive fish such as Asian silver carp Hypophthalmichthys molitrix, and crustaceans such as American signal crayfish Pacifastacus leniusculus, were found to significantly reduce the abundance of other important organisms in lakes and degrade water quality. The findings, published today in the journal Global Change Biology, also provide guidance on the best ways to manage waterbodies.

Shallow lakes naturally exist in one of two alternative stable states: either healthy - with clear water with an abundance of vegetation, or degraded - with cloudy water dominated by algae. When a lake is in the latter state, algae use up all the nutrients in the water and block sunlight, preventing the growth of aquatic vegetation that would aid ecosystem recovery.

Deteriorated, algae-dominated freshwater ecosystems also threaten the health and water security of human populations. Blooms of cyanobacteria, known as ‘blue-green algae’ can produce toxins that contaminate food webs and poison water supplies.

Zeolites’ isotopes defy nature

Ancient zeolites in Iceland. Credit: Claire Nelson

Zeolites could be considered as nature’s workhorse.

Filled with microscopic holes and channels, these ultraporous minerals can soak up environmental contaminants, filter drinking water, manage nuclear waste and even absorb carbon dioxide (CO2).

Now, in the first study of its kind, Northwestern University researchers have analyzed ancient zeolite specimens collected from the edges of East Iceland to discover that zeolites separate calcium isotopes in a wholly unexpected way.

“Calcium occurs as multiple isotopes having different masses,” said Claire Nelson, the paper’s first author. “Most minerals preferentially incorporate lighter calcium isotopes. What we found is that some zeolites prefer lighter isotopes to an extreme degree, while other zeolites prefer heavier isotopes, a rare and striking result.”

This finding could help quantify temperatures in both modern and ancient geologic systems, as well as inform efforts to mitigate human-caused climate change by carbon capture sequestration.

The study was published in the journal Communications Earth and Environment, a new open access journal established by Nature Portfolio.

“We discovered something completely unexpected and new,” said Andrew Jacobson, senior author of the study. “It could have wide ranging implications in the geosciences and across fields, especially considering that zeolites have countless applications in industry, medicine and environmental remediation.”

Researchers create ‘self-aware’ algorithm to ward off hacking attempts

Equipping computer models with “covert cognizance” could protect electric grids, manufacturing facilities and nuclear power plants from hackers, says Hany Abdel-Khalik, a Purdue associate professor of nuclear engineering. (Purdue University photo/Vincent Walter)

It sounds like a scene from a spy thriller. An attacker gets through the IT defenses of a nuclear power plant and feeds it fake, realistic data, tricking its computer systems and personnel into thinking operations are normal. The attacker then disrupts the function of key plant machinery, causing it to misperform or break down. By the time system operators realize they’ve been duped, it’s too late, with catastrophic results.

The scenario isn’t fictional; it happened in 2010, when the Stuxnet virus was used to damage nuclear centrifuges in Iran. And as ransomware and other cyberattacks around the world increase, system operators worry more about these sophisticated “false data injection” strikes. In the wrong hands, the computer models and data analytics – based on artificial intelligence – that ensure smooth operation of today’s electric grids, manufacturing facilities, and power plants could be turned against themselves.

Purdue University’s Hany Abdel-Khalik has come up with a powerful response: to make the computer models that run these cyberphysical systems both self-aware and self-healing. Using the background noise within these systems’ data streams, Abdel-Khalik and his students embed invisible, ever-changing, one-time-use signals that turn passive components into active watchers. Even if an attacker is armed with a perfect duplicate of a system’s model, any attempt to introduce falsified data will be immediately detected and rejected by the system itself, requiring no human response.

LUCY: Path to the Trojan Asteroids

 

Lucy is the first mission to explore the Jupiter Trojans – two swarms of asteroids that share Jupiter’s orbit, leading and trailing the giant planet by sixty degrees. These primitive bodies are thought to be the “fossils” of planet formation, trapped by Jupiter’s gravity at the dawn of the solar system. Now, NASA is sending Lucy on a winding, twelve-year-long path to visit one main-belt asteroid and seven Jupiter Trojans. Lucy will provide the first up-close look at these mysterious objects, helping scientists to better understand the evolution of the solar system.

YouTube Link

Source/Credit: NASA/Goddard Space Flight Center
Final Editing and Conversion: Scientific Frontline

Oldest theropod dinosaur in the UK discovered

Scientists from the Natural History Museum and the University of Birmingham have described a new species of dinosaur from specimens found in a quarry in Pant-y-ffynnon in southern Wales.

Following on from a new species of ankylosaur, Pendraig milnerae marks the second new species of dinosaur described by Museum scientists in the last few weeks.

The new dinosaur is a theropod, a group which also includes T. rex and modern birds. Pendraig milnerae is the earliest example of a theropod found in the UK so far, living between 200 and 215 million years ago during the Late Triassic period. It likely had a body size around that of a modern-day chicken and would have been a meter long including its tail.

The fragmentary fossils of the species consist of an articulated pelvic girdle, sacrum and posterior dorsal vertebrae, and an associated left femur, and by two referred specimens, comprising an isolated dorsal vertebra and a partial left ischium.

Richard Butler, co-author on the paper and Professor of Paleobiology at the University of Birmingham, said: ‘Dinosaur discoveries are really rare in Wales, and this is only the third dinosaur species known from the country. It’s very exciting to learn more about the dinosaurs that lived here in the UK during the Triassic, right at the dawn of dinosaur evolution.’

The smarter the bird, the more mental stimulation it needs in captivity, a study has found

African grey parrot Photo by Magda Ehlers from Pexels

Researchers have discovered that intelligent birds have unique welfare needs in captivity.

These findings may apply to other brainy captive creatures including great apes, elephants and whales, said the head of the research group, Dr. Georgia Mason, Director of the University of Guelph’s Campbell Centre for the Study of Animal Welfare.

“This study provides the first empirical evidence that intelligent animals can struggle in captivity,” said Dr Mason, a professor in the Department of Integrative Biology. "Our findings could help pet owners identify which species may be more challenging to cater for as pets, because of their welfare requirements” added one of the lead authors, Dr Emma Mellor from the University of Bristol.

The study, also conducted by other researchers at University of Bristol and Utrecht University in the Netherlands, revealed for the first time that this issue can in particular hinder large-brained parrots’ in confinement.

Published recently in Proceedings of the Royal Society B, the study highlights cognitive stimulation and foods that require more complicated physical handling as ways to improve care of birds.

The researchers examined two main data sources. One was an early 1990s survey on captive breeding success involving more than 30,000 birds in the United States. The team also ran an online survey involving almost 1,400 pet parrots in 50 species for stereotypic behavior: repetitive abnormal activity such as biting at cage bars, chewing or even pulling out feathers, and swaying, bouncing or route pacing in cages.

Hydrogel Tablet Can Purify a Liter of River Water in an Hour

A hydrogel tablet developed by engineers at The University of Texas at Austin can purify a liter of river water in an hour or less. Credit: The University of Texas at Austin.

As much as a third of the world’s population does not have access to clean drinking water, according to some estimates, and half of the population could live in water-stressed areas by 2025. Finding a solution to this problem could save and improve lives for millions of people, and it is a high priority among scientists and engineers around the globe.

Scientists and engineers at The University of Texas at Austin have created a hydrogel tablet that can rapidly purify contaminated water. One tablet can disinfect a liter of river water and make it suitable for drinking in an hour or less.

“Our multifunctional hydrogel can make a big difference in mitigating global water scarcity because it is easy to use, highly efficient and potentially scalable up to mass production,” said Guihua Yu, an associate professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering and Texas Materials Institute.

Yu and his team recently published their findings in the journal Advanced Materials.

Today, the primary way to purify water is to boil or pasteurize it. But that takes energy, plus a lot of time and work. That isn’t practical for people in parts of the world without the resources for these processes.

The special hydrogels generate hydrogen peroxide to neutralize bacteria at an efficiency rate of more than 99.999%. The hydrogen peroxide works with activated carbon particles to attack essential cell components of bacteria and disrupt their metabolism.

Using the hydrogel tablet to purify water requires zero energy input
and doesn’t create harmful byproducts.
Credit: The University of Texas at Austin.

The process requires zero energy input and doesn’t create harmful byproducts. The hydrogels can easily be removed, and they don’t leave any residue.

In addition to purifying water on their own, the hydrogels could also improve a process that has been around for thousands of years — solar distillation, the use of sunlight to separate water from harmful contaminants via vaporization.

Solar distillation systems often run into issues of biofouling, the accumulation of microorganisms on equipment that causes it to malfunction. The bacteria-killing hydrogels can prevent this from happening.

“A highly vigilant graduate student, Youhong Guo, discovered these hydrogels unexpectedly while doing something else, that is purification of water with sunlight,” said Keith Johnston, a professor in the McKetta Department of Chemical Engineering who co-led the project.

The team is working to improve the hydrogels by increasing the different types of pathogens and viruses in water that they can neutralize. And the team is also in the process of commercializing several prototypes.

Scaling up the hydrogels would be straightforward, the researchers say. Materials for making them are inexpensive, and the synthesis processes are simple and remain that way at large scales. And they can easily control the shape and size of the hydrogels, making them flexible for different types of uses.

Youhong Guo, a graduate student in Yu’s lab, is the first author on the paper. Graduate students Christopher Dundas from chemical engineering and Xingyi Zhou from mechanical engineering were also part of the team. The research was supported by grants from the Energy Institute at UT Austin and the Dreyfus Foundation.

Source/Credit: University of Texas at Austin

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