PALEONTOLGY

Earth's earliest forest revealed in Somerset fossils

by Cardiff University

A reconstruction of a Calamophyton forest, where trees drawn measure 2–3 meters high. 

Credit: Peter Giesen/Chris Berry

Scientists have discovered remnants of the Earth's oldest fossil forest on the north coast of Devon and Somerset in the U.K. The trees, which are about 390 million years old, are thought to have grown as part of an extensive forest covering the east coast of the Old Red Sandstone continent—part of Europe at that time.

This makes the Somerset forest 4 to 5 million years older than the previous record holder at Cairo, New York, in the U.S.

Discovered by researchers from Cambridge University and identified at Cardiff University, the fossils show incomplete trunks up to 2 meters long, together with small branches, of a pioneering type of tree called cladoxylopsids.

Cladoxylopsids dominated terrestrial ecosystems for a period of about 5 million years before the advent of more modern woody trees about 385 million years ago, according to the team.

Their findings, presented in the Journal of the Geological Society, throw new light on the evolution of trees and the transformative role they played in shaping the world we live in today.

Dr. Christopher Berry, a Senior Lecturer at Cardiff University's School of Earth and Environmental Sciences who identified the fossils, said, "These Calamophyton trees are the oldest fossil trees ever found in Britain and represent an as yet missing part of our vegetational history.

"The record of fossil forests, where tree bases are preserved where they were living, so far dates back to those discovered in New York State, at Cairo and Gilboa at about 385 million years.

"Although the area of rock exposure is limited and dangerous to access, our new discovery is the oldest clear example of such a geological phenomenon known to date and it speaks directly to the ecology of the oldest forests 390 million years ago."

At first glance, the Calamophyton resemble palm trees, but were unrelated to the kinds of trees that populate Earth today.

Credit: Cardiff University

Rather than solid wood, their trunks were hollow in the center with a ring of woody supporting strands around the outside. Instead of leaves their branches were covered in hundreds of twig-like structures.

The trees were also much shorter than their descendants, standing between 2 and 4 meters tall and as they grew, they shed their lower branches, dropping lots of vegetation litter, which supported invertebrates on the forest floor.

The team also found evidence for bases of the trees, and their fallen trunks, demonstrating for the first time the environmental context and spacing of the trees while they were living.

Dr. Berry added, "The shape and forms of these structures taken together strongly suggest that these the Calamophyton were standing alongside a raised bank beside a small river channel.

"I was able to identify the tree trunks based on 30 years studying these types of fossils and particularly having worked on the best and most complete specimens of Calamophyton from Belgium and Germany where they are well known but relatively rare.

"Nevertheless, it was a bit of a shock. Having traveled the world in search of the earliest forests, it is amazing to know that you can see the localities from here on the South Wales coast."

The team says the North Devon and Somerset site was likely located much nearer Belgium and Germany in the Devonian period, before it was relocated along a huge geological fault during the Carboniferous period at a time of crustal compression and faulting when Africa collided with Europe.

The study's first author Professor Neil Davies of Cambridge University's Department of Earth Sciences said, "The Devonian period fundamentally changed life on Earth. It also changed how water and land interacted with each other, since trees and other plants helped stabilize sediment through their root systems, but little is known about the very earliest forests.

"The evidence contained in these fossils preserves a key stage in Earth's development, when rivers started to operate in a fundamentally different way than they had before, becoming the great erosive force they are today.

"People sometimes think that British rocks have been looked at enough, but this shows that revisiting them can yield important new discoveries."

More information: Neil S. Davies et al, Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England, Journal of the Geological Society (2024). DOI: 10.1144/jgs2023-204. www.lyellcollection.org/doi/ab … /10.1144/jgs2023-204

Journal information: Journal of the Geological Society

Provided by Cardiff University 

Scientists uncover world's oldest forest

New study reveals which animals are most vulnerable to extinction due to climate change

by University of Oxford

Artistic reconstruction of a late Triassic undersea scene before (left) and after (right)

 a climate change-related extinction event. Credit: Maija Karala.

In a new study, researchers have used the fossil record to better understand what factors make animals more vulnerable to extinction from climate change. The results could help to identify species most at risk today from human-driven climate change. The findings have been published in the journal Science.

Past climate change (often caused by natural changes in greenhouse gases due to volcanic activity) has been responsible for countless species' extinctions during the history of life on Earth. But, to date, it has not been clear what factors cause species to be more or less resilient to such change, and how the magnitude of climate change affects extinction risk.

Led by researchers at the University of Oxford, this new study sought to answer this question by analyzing the fossil record for marine invertebrates (such as sea urchins, snails, and shellfish) over the past 485 million years. Marine invertebrates have a rich and well-studied fossil record, making it possible to identify when, and potentially why, species become extinct.

Using over 290,000 fossil records covering more than 9,200 genera, the researchers collated a dataset of key traits that may affect resilience to extinction, including traits not studied in depth previously, such as preferred temperature. This trait information was integrated with climate simulation data to develop a model to understand which factors were most important in determining the risk of extinction during climate change.

Key findings:

• The authors found that species exposed to greater climate change were more likely to become extinct. In particular, species that experienced temperature changes of 7°C or more across geological stages were significantly more vulnerable to extinction.
• The authors also found that species occupying climatic extremes (for instance in polar regions) were disproportionately vulnerable to extinction, and animals that could only live in a narrow range of temperatures (especially ranges less than 15°C) were significantly more likely to become extinct.
• However, geographic range size was the strongest predictor of extinction risk. Species with larger geographic ranges were significantly less likely to go extinct. Body size was also important, with smaller-bodied species more likely to become extinct.
• All of the traits studied had a cumulative impact on extinction risk. For instance, species with both small geographic ranges and narrow thermal ranges were even more susceptible to extinction than species that had only one of these traits.

Cooper Malanoski (Department of Earth Sciences, University of Oxford), first author of the study, said, "Our study revealed that geographic range was the strongest predictor of extinction risk for marine invertebrates, but that the magnitude of climate change is also an important predictor of extinction, which has implications for biodiversity today in the face of climate change."

With current human-driven climate change already pushing many species up to and beyond the brink of extinction, these results could help identify the animals that are most at risk, and inform strategies to protect them.

Lead author Professor Erin Saupe (Department of Earth Sciences, University of Oxford) said, "The evidence from the geological past suggests that global biodiversity faces a harrowing future, given projected climate change estimates.

"In particular, our model suggests that species with restricted thermal ranges of less than 15°C, living in the poles or tropics, are likely to be at the greatest risk of extinction. However, if the localized climate change is large enough, it could lead to significant extinction globally, potentially pushing us closer to a sixth mass extinction."

Infographic summarising the key traits and factors identified by the study that 

determine species risk to climate change-related extinction. 

Credit: Miranta Kouvari (Science Graphic Design).

According to the research team, future work should explore how climate change interacts with other potential drivers of extinction, such as ocean acidification and anoxia (where seawater becomes depleted of oxygen).

The study also involved researchers from the School of Geographical Sciences, University of Bristol. Professor Dan Lunt, from the University of Bristol, said, "This study shows that over the course of Earth's history, the extinction risk of marine life has been inextricably linked to climate change. This should act as a stark warning to humanity as we recklessly continue to cause climate change ourselves through burning fossil fuels."

More information: Cooper M. Malanoski et al, Climate change is an important predictor of extinction risk on macroevolutionary timescales, Science (2024). DOI: 10.1126/science.adj5763. www.science.org/doi/10.1126/science.adj5763

Journal information: Science 

Provided by University of Oxford Mathematician creates mass extinction model regarding climate change and adaptation

PATHOLOGY/VIROLOGY

Report calls for regulations around dangerous pathogen research

Researcher working in fume hood

March 7, 2024 – In recent years, concerns have been raised about the dangers of research on risky pathogens—the kind that could trigger a pandemic. In February, a task force convened by the Bulletin of Atomic Scientists released a report that makes recommendations on strategies for conducting such research, calling for stronger oversight. Harvard T.H. Chan School of Public Health’s Marc Lipsitch served on the task force. Lipsitch, professor of epidemiology and director of the Center for Communicable Disease Dynamics at Harvard T.H. Chan School of Public Health, discusses key takeaways from the new report.

What was the impetus behind this report?

There’s a growing realization in many quarters that while most biological research is completely safe or poses risks only to a small number of individuals involved in research, there’s a very small subset of biological research that poses risks beyond the individuals involved, because it involves the potential for an accident or a deliberate misuse that could lead to widespread transmission of the agent being studied.

The issue is quite polarized between some individuals who suggest that scientists should be able to regulate themselves and there’s no need for outside oversight, and others who have proposed, and in some cases enacted, bans on whole categories of research at the state level, for example in Florida.

The task force was by design a very international, cross-disciplinary group, including virologists, epidemiologists, biosafety experts, social scientists, a philosopher, and others. The idea was to find some kind of common ground on what is the scope of research that needs to be more carefully scrutinized and what that scrutiny might be.

What was amazing about the process was that, despite different backgrounds and in some cases different starting positions, we were able to come to agreement on a set of principles that, if taken seriously by those designing policies, really has some teeth.

What are some key takeaways from the report?

The most important thing is that this group acknowledges that there is a scope for special regulation of the types of research that risk a pandemic. This sort of research is a small subset, but a particularly risky subset. We also state that this is not a matter for science to self-regulate. It’s a matter for public consideration, and the public has a right to be a part of the process.

The second key takeaway is that the report gets specific about the types of research that are of top concern: research with known pandemic pathogens; research that could somehow create a pandemic pathogen; and research with pathogens of unknown risk.

A third takeaway has to do with equity, which has been lacking in the discussion in the past. It is an unfortunate but true fact that the benefits of scientific research come first, in most cases, to the developed world, and only later, if at all, to the rest of the world. That means that research that promises potential biomedical benefits at the risk of possibly starting a pandemic is just further disadvantaging groups that have already been disadvantaged, because they don’t have first crack at the benefits and are likely to face disproportionate risks.

Another key principle articulated in the report is that researchers should look as hard as possible for safer alternatives to risky research.

Was there anything particularly controversial or tricky as you and the other task force members worked on the report?

The particulars about the kinds of risks, how big they are, and what the benefits need to be—that did require some judgment. There was a lot of discussion in the group about how strongly to assert the need for a public health benefit to offset a public health risk. My preferred interpretation is that the scientific benefit alone is not good enough—that you need a clear path to a public health benefit before you should accept any risk to public health.

How do you foresee the report’s recommendations being implemented?

You would have to have some kind of local, national, or institutional implementation. But the principles outlined in the report are global and the enforcement or the incentives should be global. Journals would play an important role. For example, if a researcher did something that didn’t get proper scrutiny, a journal should not accept it for publication.

What’s happening in the U.S. regarding oversight of risky pathogen research?

At the moment, there is a panel within the Department of Health and Human Services that reviews some of this research, but their identities and deliberations are secret. Our task force would like to see greater transparency in the process. In the meantime, the federal government is considering updating the framework that governs this review process. I hope that the update comes out soon and is consistent with the kind of recommendations we’ve outlined in this report.

What are your thoughts on the level of risk the word faces right now from a lab leak that could start another pandemic?

I don’t know the magnitude of the risk. I just know that it’s our responsibility to minimize it.

– Karen Feldscher

Photo: iStock/pkujiahe

 

Researchers reveal how a virus hijacks insect sperm: May help control disease vectors and pests

by Pennsylvania State University

A new study led by researchers at Penn State has uncovered how a widespread bacteria 

called Wolbachia and a virus that it carries—tagged with fluorescence in this image of 

Drosophila testes—can cause sterility in male insects by hijacking their sperm. 

This prevents the insects from fertilizing eggs of females that do not have the same 

combination of bacteria and virus. These findings could improve techniques to control

 populations of agricultural pests and insects that carry diseases like Zika and dengue to 

humans. Credit: Rupinder Kaur/Penn State

A widespread bacteria called Wolbachia and a virus that it carries can cause sterility in male insects by hijacking their sperm, preventing them from fertilizing eggs of females that do not have the same combination of bacteria and virus.

A new study led by microbiome researchers at Penn State has uncovered how this microbial combination manipulates sperm, which could lead to refined techniques to control populations of agricultural pests and insects that carry diseases like Zika and dengue to humans.

The study is published in the journal Science.

"Wolbachia is the most widespread bacteria in animals and lives symbiotically within the reproductive tissues of about 50% of insect species, including some mosquitos and flies," said Seth Bordenstein, professor of biology and entomology, director of the One Health Microbiome Center at Penn State, and one of the leaders of the research team.

"Wolbachia has genes from a virus called prophage WO integrated into its genome. These genes—cifA and cifB—allow the bacteria to remarkably manipulate sperm and quickly spread through an insect population for their own good."

When a male and female insect that both have Wolbachia mate, they successfully reproduce and pass on the bacteria. But when a male with Wolbachia mates with a female with no Wolbachia, the sperm are rendered lethal to the fertilized eggs, succumbing them to death. This system cunningly increases the proportion of offspring with Wolbachia and the virus in the next generation, because females with the bacteria successfully reproduce more frequently than females without.

This system is being used in several ongoing pilot studies across the world to control insect pests and the harmful viral diseases they carry. For example, to control a population of agricultural or human pests that do not have the bacteria, scientists release males with Wolbachia in order to crash the population.

A new study led by researchers at Penn State has uncovered how a widespread bacteria called Wolbachia and the WO virus that it carries can cause sterility in male insects by hijacking their sperm. These findings could improve techniques to control populations of agricultural pests and insects that carry diseases like Zika and dengue to humans. Credit: Penn State

"One of Wolbachia's superpowers is that it blocks pathogenic RNA viruses such as Zika, dengue and chikungunya virus, so mosquitos with Wolbachia do not pass these viruses on to people when they bite," Bordenstein said.

"So, releases of both male and female mosquitos with Wolbachia in an area where it isn't already present leads to replacement of the population with mosquitos that can no longer pass on a viral disease. The World Mosquito Program is now using Wolbachia to control viruses in 11 countries. With this study, we reveal the underlying mechanics of how this process works so we can fine-tune the technique to expand its scope in vector control measures."

Wolbachia's prophage WO genes code for proteins that interfere with normal development of sperm cells. These proteins impact a critical transformation during sperm development, when the sperm's genome is repackaged and the sperm changes from a canoe-shape into a more refined needle-like shape.

"This shape change is incredibly important to the success of sperm, and any interference can impact the sperm's ability to travel in the female reproductive tract and successfully fertilize the egg," said Rupinder Kaur, assistant research professor of biology and entomology at Penn State and the other leader of the research team.

"The transition is highly conserved in almost everything from insects to humans. Defects in this process can also cause male sterility in humans."

According to the researchers, sperm is particularly prone to DNA damage and repair during this transition. In this study, they found that sperm exposed to Wolbachia, or the Cif proteins alone, had an elevated level of DNA damage at this stage. The DNA damage, if not repaired in a timely fashion, can result in abnormal sperm genome packaging, male infertility and embryonic inviability.

"These results confirmed the impact of Wolbachia and Cif proteins at this stage of sperm development, but we still wanted to know what was happening at earlier stages to trigger these changes," Kaur said.

"We conducted a series of tests to explore the structure and biochemical function of the Cif proteins and found that they can cleave messenger molecules called long non-coding RNA, which sets the stage to interfere with downstream development and function of the sperm."

The researchers used fruit flies with Wolbachia to test the potential link between the bacteria and long non-coding RNA. They found that Wolbachia—or the Cif proteins alone—reduced the amount of these RNAs. Additionally, mutant flies with reduced expression of these RNAs in conjunction with Wolbachia had elevated levels of embryonic inviability because it augmented the defective transition process of sperm development.

So, Kaur explained, the virus proteins control sperm by depleting the long non-coding RNAs required for a normal sperm function.

"Long non-coding RNAs do not make any proteins themselves, but they can have profound impacts on regulating the function of other genes required for sperm development," Bordenstein said.

"By altering this non-coding part of the genome, we found that Cif proteins start impacting sperm right from the earliest stages of development. Wolbachia's prophage WO genes act like master puppeteers, manipulating sperm development in a way that allows their genes and the symbiotic bacteria to quickly spread through arthropod populations."

Because the process of sperm development looks similar across the animal kingdom, the researchers said that knowledge of this process could lend insight into sterility challenges in humans as well as inform new control methods of harmful insect populations.

"Now that we have reverse engineered this process, we can fine-tune methods of population control with Wolbachia that are already in use," Kaur said.

"We plan to take advantage of this knowledge to augment currently existing disease vector and pest control methods, and perhaps emulate the technique without Wolbachia or virus proteins in the long-term."

More information: Rupinder Kaur et al, Prophage proteins alter long noncoding RNA and DNA of developing sperm to induce a paternal-effect lethality, Science (2024). DOI: 10.1126/science.adk9469. www.science.org/doi/10.1126/science.adk9469

Journal information: Science 

Provided by Pennsylvania State University Fight against Zika, dengue get boost from reliable spread of bacteria

Deadly Diseases That Plagued People in Ancient Times are Similar to Those of Today

In a time before modern medicine, humanity was plagued with a host of diseases that are now easily cured or prevented. But some are still with us even today.

By Sean Mowbray

Mar 7, 2024 

A physician (center front) is taking the pulse of a patient while he breaths through sponge soaked in herbs to protect against evil emanations from the victim. (Credit: Everett Collection/Shutterstock)

For many people in the ancient world, life was no casual stroll around the Forum. Today, many diseases can be treated with modern medicine or prevented entirely, thanks to the development of myriad vaccines to help rid us of the risk of infection (though major inequalities still mean such lifesaving shots are not available to all).

In ancient times, however, these advances simply were not available, making disease an ever present and deadly risk. Kyle Harper, professor of classics and letters at the University of Oklahoma, says that in ancient times life expectancies were so low in part because infectious diseases were such a powerful force.  

“They didn't have the biomedical and public health resources that we enjoy today,” he adds. Healthcare to some degree did exist in the ancient world and medical advances were made, but treatment often revolved around dubious remedies, charms, and superstitions

“The class of diseases that are caused by some kind of microbial invader were one of the most fundamental facts shaping every premodern society,” Harper says.

Tuberculosis and Malaria in Ancient Times

(Credit: Everett Collection/Shutterstock)

Today, the average global life expectancy is around 70 years of age and continues to increase, but centuries ago, that was hardly the case. In ancient Egypt, it’s believed that the average age at death was as low as 19, mainly due to high infant death rates. The average lifespan of a man is thought to have been around 25. In ancient Greece and Rome, people fared little better as some estimates place the expectancy range between 20 and 35 years.

Attributing to these low life spans, many of the diseases that ancient peoples faced are still recurrent health problems today. Tuberculosis, for example, has ravaged human populations for thousands of years. Egyptian mummies from around 2400 B.C.E. show deformities similar to TB and ancient texts from China and India may refer to it, according to research.

The disease was known as phthisis to the ancient Greeks and the physician Hippocrates reports that many in his homeland succumbed to the illness. Today, over a million people continue to die of TB each year, even though it is both curable and preventable.

Malaria too was likely endemic in ancient Egypt and Nubia, alongside other diseases such as leishmaniasis and schistosomiasis. Two mummies buried around 3,500 years ago likely died of malaria, making them the two earliest known cases of the mosquito-borne disease. 

It’s also known that malaria was prevalent in certain regions of the Roman Empire and DNA evidence shows that the malaria was present across Italy in ancient times.

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A range of other diseases hammered ancient civilizations, including cancer, which Hippocrates described, ultimately giving it its name. Similarly, one of the first descriptions of rabies dates back to Greece around 500 B.C.E.

The Roman writer Pliny the Elder describes how those who are bitten by dogs with “canine madness” develop a deadly horror of water, and outlines curious remedies to combat the disease. 

Parasites and Pandemics

Tapeworms. (Credit: Rattiya Thongdumhyu/Shutterstock)

On top of this massive health burden came others, such as gastrointestinal diseases and parasites such as worms, the impact of which are easy to underestimate, says Harper. Studies indicate that people living in the ancient world were regularly exposed to and riddled with different kinds of intestinal worms.

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Read More: The Biggest Parasite Can Grow Up to 30 Feet Long, and Live in Your Stomach

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Pandemics also rocked the ancient world. Back in 430 B.C.E., a plague hammered the besieged city of Athens. Over the course of three years, it’s estimated that as many as 100,000 people may have died, representing around one quarter of the city’s population at that time. What caused this particular plague remains somewhat of a mystery.

“The Roman world seems to have experienced a number of really explosive, consequential pandemic disease events,” adds Harper, who has authored books on that same subject.

The Antonine Plague – which occurred between 165 and 180 C.E. – is estimated to have killed around 2,000 people per day in Rome at its peak, even claiming the life of Lucius Verus, co-emperor alongside Marcus Aurelius. It’s unclear what caused the outbreak, says Harper, but suggestions include measles or an ancestral form of smallpox.

Similarly, the Plague of Cyprian occurred between 250 and 270 C.E. It originated in Ethiopia before spreading across the Mediterranean region and beyond; its death toll may have reached as high as 5,000 people per day in Rome, according to estimates. Like the Antonine Plague before it, there is speculation about its cause.

Harper says that it may have been viral hemorrhagic fever, while other possibilities include typhus, measles or meningitis. “Until we get DNA evidence, we are going to have trouble saying what caused the plague,” he notes.

Another Plague, Same as the Black Death

Yersinia pestis bacteria which caused Bubonic Plague. (Credit: Everett Collection/Shutterstock)

Such evidence does exist for the later, and far more devastating, Plague of Justinian. This erupted in 541 C.E. and continued to claim lives across the Mediterranean for over 200 years. 

“The Plague of Justinian in the 540s is the only one where we know with absolute certainty what caused it,” Harper says. “It was bubonic plague.”

Spread by black rats, this plague is the same culprit behind the infamous Black Death that rocked Medieval Europe between 1347 to 1351, killing millions of people. Harper describes it as “the most explosive pandemic disease in human history.”

By the time the outbreak ended, it’s believed that between 25 to 50 million may have died across the Mediterranean, though this is debated.

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Read More: Scientists Reveal the Black Death’s Origin Story

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Our writers at Discovermagazine.com use peer-reviewed studies and high quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

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