<![CDATA[Scivillage.com Casual Discussion Science Forum - Biochemistry, Biology & Virology ]]> https://www.scivillage.com/ Thu, 16 Apr 2026 22:36:36 +0000 MyBB <![CDATA[Are Genes Like Nanobots?]]> https://www.scivillage.com/thread-20176.html Mon, 13 Apr 2026 14:55:49 +0000 Zinjanthropos]]> https://www.scivillage.com/thread-20176.html
So are they living material, bits of information, or natural machinery? Is there any organism alive today that doesn’t have genes? Or can genes exist outside an organism and come and go? Do they need energy and if so where does it come from? Without the food intake of an organism do genes slow down, stop working or die first?]]>
So are they living material, bits of information, or natural machinery? Is there any organism alive today that doesn’t have genes? Or can genes exist outside an organism and come and go? Do they need energy and if so where does it come from? Without the food intake of an organism do genes slow down, stop working or die first?]]> <![CDATA[India is the global accelerant for antibiotic resistant bacteria]]> https://www.scivillage.com/thread-20150.html Thu, 09 Apr 2026 12:30:35 +0000 C C]]> https://www.scivillage.com/thread-20150.html https://aeon.co/essays/antibiotic-resist...everywhere

EXCERPT: India is the accelerant of the global antimicrobial resistance crisis. Weak governance of pharmaceuticals, easy access to antibiotics, a high burden of infection driven by gaps in sanitation and health infrastructure, prolific antibiotic use in agriculture, and industrial pollution from pharmaceutical and other waste streams have combined to speed the rise and spread of resistant bacteria.

In a connected world, those microbes and resistant genes will not remain local.

They may travel in the gut of an unwitting tourist or circulate through the body of a worker in India. But resistance is not contained within individual bodies. It moves through wider systems, from sewage and waste to farms, food chains and global trade. Superbugs emerge in densely packed farms outside India’s megacities and in shrimp ponds supplying supermarkets in the United States. There, antibiotics do more than treat disease. They help sustain intensive production, deliver cheap protein, protect farmers’ incomes and secure corporate profit.

Resistant bacteria also gather around pharmaceutical manufacturing plants in South India. Wastewater from some of these facilities has repeatedly been found to contain antibiotic residues and resistance genes. At the same time, some manufacturers produce substandard or spurious antibiotics for both foreign and domestic markets. These are two distinct routes into the same problem. Environmental contamination exposes bacteria to a mixture of chemicals and low levels of antibiotic residues, helping the hardiest survive and multiply. Poor-quality drugs allow bacteria to persist, making treatment less effective next time. Either way, the phenomenon is the fuel behind MRSA bacteria, drug-resistant tuberculosis, and the highly resistant strains of E coli, Klebsiella and Acinetobacter. Then, such microbes and their resistance genes cross borders through travel, trade, food systems, displacement, conflict and global supply chains.

[...] Across India, antibiotics are regarded as ‘strong medicine’: a fast and familiar solution when there is neither time nor money for a proper diagnosis and medically supervised treatment. Decades of routine use by millions of Indians – rich and poor alike – have reinforced the sense that antibiotics work and are just part of day-to-day life. They are cheap, widely available through thousands of streetside pharmacies and, for most people, seemingly free of immediate side effects.

When we asked Sushil why he dispenses antibiotics so readily, his answer was direct: ‘I cannot risk a person’s life. If someone comes from the village and doesn’t have money, what will I do? I’ll give them antibiotics for three days. I cannot just let go of their life.’ (MORE - missing details)]]> https://aeon.co/essays/antibiotic-resist...everywhere

EXCERPT: India is the accelerant of the global antimicrobial resistance crisis. Weak governance of pharmaceuticals, easy access to antibiotics, a high burden of infection driven by gaps in sanitation and health infrastructure, prolific antibiotic use in agriculture, and industrial pollution from pharmaceutical and other waste streams have combined to speed the rise and spread of resistant bacteria.

In a connected world, those microbes and resistant genes will not remain local.

They may travel in the gut of an unwitting tourist or circulate through the body of a worker in India. But resistance is not contained within individual bodies. It moves through wider systems, from sewage and waste to farms, food chains and global trade. Superbugs emerge in densely packed farms outside India’s megacities and in shrimp ponds supplying supermarkets in the United States. There, antibiotics do more than treat disease. They help sustain intensive production, deliver cheap protein, protect farmers’ incomes and secure corporate profit.

Resistant bacteria also gather around pharmaceutical manufacturing plants in South India. Wastewater from some of these facilities has repeatedly been found to contain antibiotic residues and resistance genes. At the same time, some manufacturers produce substandard or spurious antibiotics for both foreign and domestic markets. These are two distinct routes into the same problem. Environmental contamination exposes bacteria to a mixture of chemicals and low levels of antibiotic residues, helping the hardiest survive and multiply. Poor-quality drugs allow bacteria to persist, making treatment less effective next time. Either way, the phenomenon is the fuel behind MRSA bacteria, drug-resistant tuberculosis, and the highly resistant strains of E coli, Klebsiella and Acinetobacter. Then, such microbes and their resistance genes cross borders through travel, trade, food systems, displacement, conflict and global supply chains.

[...] Across India, antibiotics are regarded as ‘strong medicine’: a fast and familiar solution when there is neither time nor money for a proper diagnosis and medically supervised treatment. Decades of routine use by millions of Indians – rich and poor alike – have reinforced the sense that antibiotics work and are just part of day-to-day life. They are cheap, widely available through thousands of streetside pharmacies and, for most people, seemingly free of immediate side effects.

When we asked Sushil why he dispenses antibiotics so readily, his answer was direct: ‘I cannot risk a person’s life. If someone comes from the village and doesn’t have money, what will I do? I’ll give them antibiotics for three days. I cannot just let go of their life.’ (MORE - missing details)]]> <![CDATA[Spectacular fossil treasure trove pushes back origins of complex animals]]> https://www.scivillage.com/thread-20103.html Thu, 02 Apr 2026 19:28:07 +0000 C C]]> https://www.scivillage.com/thread-20103.html https://www.eurekalert.org/news-releases/1121553

INTRO: A newly discovered fossil site in southwest China has transformed our understanding of how complex animal life emerged on Earth, revealing that many key animal groups had already evolved before the start of the Cambrian Period. The study, led by researchers at Oxford University’s Museum of Natural History and Department of Earth Sciences as well as Yunnan University in China, has been published today (02 April) in Science.

One of the most transformative events in Earth’s history was the rapid diversification of animal life, resulting in a dramatic increase in complexity and diversity from simpler life forms. Up to now, this was thought to have occurred at the start of the Cambrian Period, in an event known as the Cambrian explosion, starting around 535 million years ago. The new study, however, shifts this timeframe back by at least 4 million years, to the end of the Ediacaran period.

Lead author Dr Gaorong Li (Yunnan University at the time of the study, now Museum of Natural History, Oxford University), said: “Our discovery closes a major gap in the earliest phases of animal diversification. For the first time, we demonstrate that many complex animals, normally only found in the Cambrian, were present in the Ediacaran period, meaning that they evolved much earlier than previously demonstrated by fossil evidence.”

The discovery comes from the Jiangchuan Biota in Yunnan Province, southwest China, where more than 700 fossil specimens were recovered, aged between 554 and 539 million years old. The fossil site revealed a diverse community of Ediacaran organisms - both new, undescribed animal forms and groups known from the Cambrian period.

Most strikingly, the international team identified fossils thought to be the oldest known relatives of deuterostomes – the broader group that today includes vertebrates such as humans and fish. The new fossils push the fossil record of deuterostomes back into the Ediacaran Period for the first time.

Among these fossil specimens were ancestors of modern starfish and their closest relatives, the acorn worms (the Ambulacraria). These fossils have a U-shaped body and were attached to the seafloor with a stalk, with a pair of tentacles on their head used to catch food.

Co-author Dr Frankie Dunn (Museum of Natural History, Oxford University) said: “The presence of these ambulacrarians in the Ediacaran period is really exciting. We have already found fossils which are distant relatives of starfish and sea cucumbers and are looking for more. The discovery of ambulacrarian fossils in the Jiangchuan biota also means that the chordates – animals with a backbone – must also have existed at this time.”

Other ancestral groups among the fossils included worm-like bilaterian animals (having bilateral symmetry), some with complex feeding adaptations, alongside rare fossils interpreted as early comb jellies.

Many specimens showed novel combinations of anatomical features (such as tentacles, stalks, attachment discs, and feeding structures that can be turned inside out) that do not match any known Ediacaran or Cambrian species. “For instance, one specimen looks a lot like the sand worm from Dune!” Dr Dunn added.

Co-author Associate Professor Luke Parry (Department of Earth Sciences, Oxford University) added: “This discovery is extremely exciting because it reveals a transitional community: the weird world of the Ediacaran giving way to the Cambrian, the following time period where the animals are much easier to place in groups that are alive today. When we first saw these specimens, it was clear that this was something totally unique and unexpected.”

The new findings help to resolve a long-standing puzzle in evolutionary biology. While molecular studies and trace fossils suggested that animal lineages diversified well before the Cambrian explosion, up to now fossils of many of these groups of complex animals have been missing from the Ediacaran period... (MORE - details)]]> https://www.eurekalert.org/news-releases/1121553

INTRO: A newly discovered fossil site in southwest China has transformed our understanding of how complex animal life emerged on Earth, revealing that many key animal groups had already evolved before the start of the Cambrian Period. The study, led by researchers at Oxford University’s Museum of Natural History and Department of Earth Sciences as well as Yunnan University in China, has been published today (02 April) in Science.

One of the most transformative events in Earth’s history was the rapid diversification of animal life, resulting in a dramatic increase in complexity and diversity from simpler life forms. Up to now, this was thought to have occurred at the start of the Cambrian Period, in an event known as the Cambrian explosion, starting around 535 million years ago. The new study, however, shifts this timeframe back by at least 4 million years, to the end of the Ediacaran period.

Lead author Dr Gaorong Li (Yunnan University at the time of the study, now Museum of Natural History, Oxford University), said: “Our discovery closes a major gap in the earliest phases of animal diversification. For the first time, we demonstrate that many complex animals, normally only found in the Cambrian, were present in the Ediacaran period, meaning that they evolved much earlier than previously demonstrated by fossil evidence.”

The discovery comes from the Jiangchuan Biota in Yunnan Province, southwest China, where more than 700 fossil specimens were recovered, aged between 554 and 539 million years old. The fossil site revealed a diverse community of Ediacaran organisms - both new, undescribed animal forms and groups known from the Cambrian period.

Most strikingly, the international team identified fossils thought to be the oldest known relatives of deuterostomes – the broader group that today includes vertebrates such as humans and fish. The new fossils push the fossil record of deuterostomes back into the Ediacaran Period for the first time.

Among these fossil specimens were ancestors of modern starfish and their closest relatives, the acorn worms (the Ambulacraria). These fossils have a U-shaped body and were attached to the seafloor with a stalk, with a pair of tentacles on their head used to catch food.

Co-author Dr Frankie Dunn (Museum of Natural History, Oxford University) said: “The presence of these ambulacrarians in the Ediacaran period is really exciting. We have already found fossils which are distant relatives of starfish and sea cucumbers and are looking for more. The discovery of ambulacrarian fossils in the Jiangchuan biota also means that the chordates – animals with a backbone – must also have existed at this time.”

Other ancestral groups among the fossils included worm-like bilaterian animals (having bilateral symmetry), some with complex feeding adaptations, alongside rare fossils interpreted as early comb jellies.

Many specimens showed novel combinations of anatomical features (such as tentacles, stalks, attachment discs, and feeding structures that can be turned inside out) that do not match any known Ediacaran or Cambrian species. “For instance, one specimen looks a lot like the sand worm from Dune!” Dr Dunn added.

Co-author Associate Professor Luke Parry (Department of Earth Sciences, Oxford University) added: “This discovery is extremely exciting because it reveals a transitional community: the weird world of the Ediacaran giving way to the Cambrian, the following time period where the animals are much easier to place in groups that are alive today. When we first saw these specimens, it was clear that this was something totally unique and unexpected.”

The new findings help to resolve a long-standing puzzle in evolutionary biology. While molecular studies and trace fossils suggested that animal lineages diversified well before the Cambrian explosion, up to now fossils of many of these groups of complex animals have been missing from the Ediacaran period... (MORE - details)]]> <![CDATA[Explanation for why we don't see two-foot-long dragonflies anymore fails]]> https://www.scivillage.com/thread-20084.html Tue, 31 Mar 2026 00:21:20 +0000 C C]]> https://www.scivillage.com/thread-20084.html https://arstechnica.com/science/2026/03/...-squashed/

EXCERPTS: Three-hundred million years ago, the skies of the late Palaeozoic era were buzzing with giant insects. Meganeuropsis permiana, a predatory insect resembling a modern-day dragonfly, had a wingspan of over 70 centimeters and weighed 100 grams. Biologists looked at these ancient behemoths and asked why bugs aren’t this big anymore. Thirty years ago, they came up with an answer known as the “oxygen constraint hypothesis.”

For decades, we thought that any dragonflies the size of hawks needed highly oxygenated air to survive because insect breathing systems are less efficient than those of mammals, birds, or reptiles. As atmospheric oxygen levels dropped, there wasn’t enough to support giant bugs anymore. “It’s a simple, elegant explanation,” said Edward Snelling, a professor of veterinary science at the University of Pretoria. “But it’s wrong.”

Unlike mammals, insects don’t have a centralized pair of lungs and a closed circulatory system that delivers oxygen-rich blood to their tissues. “They breathe through internalized tubing called the tracheal system,” Snelling explained.

[...] Here, oxygen delivery relies on passive diffusion to cross the final barrier into the tissue. The problem with diffusion is that it’s notoriously slow. The oxygen constraint hypothesis argued that the larger the insect grows, the further the oxygen must travel to reach the deepest tissues. “As the insects get bigger and bigger, the challenge of diffusion becomes greater,” Snelling said.

[...] The late Palaeozoic was a time of hyperoxia, with atmospheric oxygen levels peaking around 30 percent, compared to the 21 percent we breathe today. Hyperoxia was supposed to let insects bypass the limitations of their breathing system and grow larger. But recently, Snelling led a team of researchers that tested this idea, as they describe in a recent Nature study. It just didn’t hold up.

[...] To put it simply, if a giant insect needed more oxygen, evolving a denser network of tracheoles would be a cheap and effective physiological upgrade. There was likely no anatomical roadblock stopping them from doing so, and they probably wouldn’t have to sacrifice flying power to achieve it.

But if the lack of oxygen didn’t kill the giant bugs, we’re still faced with an outstanding question: What’s stopping our present bugs from evolving to the size of a pigeon? “There are a few hypotheses that are out there,” Snelling said.

[...] One hypothesis is the rise of aerial vertebrate predators. The fossil record shows a decoupling between maximum insect wing length and atmospheric oxygen levels starting at around 135 million years ago, which roughly coincides with the evolution of birds and, later, bats. “This predatory pressure didn’t exist 300 million years ago,” Snelling said.

[...] Then there’s an issue of growing XL-sized exoskeletons. Insects must molt to grow. When they shed their hard outer shells, they are temporarily soft and squishy until the new exoskeleton hardens. Surface tension and basic structural mechanics can hold this soft body together in a tiny beetle, but they might struggle to do so if the bug is much larger... (MORE - missing details)

PAPER: https://doi.org/10.1038/s41586-026-10291-3]]> https://arstechnica.com/science/2026/03/...-squashed/

EXCERPTS: Three-hundred million years ago, the skies of the late Palaeozoic era were buzzing with giant insects. Meganeuropsis permiana, a predatory insect resembling a modern-day dragonfly, had a wingspan of over 70 centimeters and weighed 100 grams. Biologists looked at these ancient behemoths and asked why bugs aren’t this big anymore. Thirty years ago, they came up with an answer known as the “oxygen constraint hypothesis.”

For decades, we thought that any dragonflies the size of hawks needed highly oxygenated air to survive because insect breathing systems are less efficient than those of mammals, birds, or reptiles. As atmospheric oxygen levels dropped, there wasn’t enough to support giant bugs anymore. “It’s a simple, elegant explanation,” said Edward Snelling, a professor of veterinary science at the University of Pretoria. “But it’s wrong.”

Unlike mammals, insects don’t have a centralized pair of lungs and a closed circulatory system that delivers oxygen-rich blood to their tissues. “They breathe through internalized tubing called the tracheal system,” Snelling explained.

[...] Here, oxygen delivery relies on passive diffusion to cross the final barrier into the tissue. The problem with diffusion is that it’s notoriously slow. The oxygen constraint hypothesis argued that the larger the insect grows, the further the oxygen must travel to reach the deepest tissues. “As the insects get bigger and bigger, the challenge of diffusion becomes greater,” Snelling said.

[...] The late Palaeozoic was a time of hyperoxia, with atmospheric oxygen levels peaking around 30 percent, compared to the 21 percent we breathe today. Hyperoxia was supposed to let insects bypass the limitations of their breathing system and grow larger. But recently, Snelling led a team of researchers that tested this idea, as they describe in a recent Nature study. It just didn’t hold up.

[...] To put it simply, if a giant insect needed more oxygen, evolving a denser network of tracheoles would be a cheap and effective physiological upgrade. There was likely no anatomical roadblock stopping them from doing so, and they probably wouldn’t have to sacrifice flying power to achieve it.

But if the lack of oxygen didn’t kill the giant bugs, we’re still faced with an outstanding question: What’s stopping our present bugs from evolving to the size of a pigeon? “There are a few hypotheses that are out there,” Snelling said.

[...] One hypothesis is the rise of aerial vertebrate predators. The fossil record shows a decoupling between maximum insect wing length and atmospheric oxygen levels starting at around 135 million years ago, which roughly coincides with the evolution of birds and, later, bats. “This predatory pressure didn’t exist 300 million years ago,” Snelling said.

[...] Then there’s an issue of growing XL-sized exoskeletons. Insects must molt to grow. When they shed their hard outer shells, they are temporarily soft and squishy until the new exoskeleton hardens. Surface tension and basic structural mechanics can hold this soft body together in a tiny beetle, but they might struggle to do so if the bug is much larger... (MORE - missing details)

PAPER: https://doi.org/10.1038/s41586-026-10291-3]]> <![CDATA[5 seriously strange ways wildlife is changing inside Chernobyl]]> https://www.scivillage.com/thread-20060.html Thu, 26 Mar 2026 18:36:04 +0000 C C]]> https://www.scivillage.com/thread-20060.html https://www.sciencefocus.com/nature/5-se...-chernobyl

EXCERPTS: I first visited Chernobyl in 2016, 30 years after the explosion at Reactor Four. I expected silence and scarcity – a lifeless place, defined by radiation. Instead, I found beavers swimming beneath a nuclear power plant.

When the reactor exploded on 26 April 1986, many assumed the surrounding land would be biologically dead for generations. The exclusion zone – the area where radiation is highest and access is still restricted – covers roughly 2,600 km² on the Ukrainian side, about the size of Luxembourg.

When neighbouring areas of Belarus are included, the affected landscape stretches to more than 4,500 km². With that as a starting point, it was hard to imagine a future Chernobyl that was anything other than a wasteland.

In the days and months that followed, the evidence seemed to support that view. The pine forests closest to the plant absorbed such intense radiation that their needles turned an orange-red and died, creating what became known as the Red Forest. Early studies reported small mammals and invertebrates were disappearing in heavily contaminated areas.

And yet, 30 years on, there I was, watching dark heads cut slow arcs through the cooling ponds at the Chernobyl Nuclear Power Plant itself, beneath the vast concrete shell of reactor four. A glance upward reminded me this water had been engineered to keep a nuclear reactor from overheating. Now it held a functioning dam with beavers behaving like beavers.

Chernobyl’s mythology presents the place as being filled with grotesque mutations – two-headed fish and other monstrosities. Instead, a white-tailed eagle and a migrating osprey fished as if this were any other wetland.

Great white egrets worked the shallows in the reactor’s shadow. A grey wolf burst briefly from the reeds, then vanished again – running away, not patrolling some apocalyptic wasteland.

What people expect from Chernobyl is a catastrophe frozen in place: ruins, silence, and a landscape visibly broken.

Now, nearly 40 years on, the exclusion zone has become one of the most unusual ecological experiments on Earth, shaped not just by radiation but by abandonment and time. The usual ecological rules no longer apply, leading Chernobyl to have some truly weird wildlife.

Usually, large animals are the first to disappear after an environmental disaster. They reproduce slowly, require large territories, and are especially vulnerable to human pressure. But in Chernobyl, they’re thriving.

[...] And at first glance, it doesn’t appear that the radiation is bothering them. People often imagine Chernobyl’s wildlife is filled with monsters born of radiation, but scientists working in the zone are keen to reset those expectations.

Clear, dramatic physical deformities in large mammals are rarely documented because animals born with severe abnormalities rarely survive long enough to be observed. Meanwhile, the relatively short lifespans of wild mammals mean long-term effects are difficult to detect in the field.

The absence of monsters does not mean the absence of impact, of course, but it does mean that the impacts are not playing out in the ways popular culture expects. Instead, the decisive factor appears to be the sudden absence of people. Hunting stopped. Roads fell apart. Farming ceased. Human disturbance – often the most consistent pressure on large wildlife – dropped almost overnight.

“This matters,” says evolutionary biologist Germán Orizaola, who has been studying the effects of radiation in Chernobyl since the spring of 2016, “because if you focus on the species that are doing badly, you can blame radiation. But often the environment itself has changed. Ecology and the absence of humans are huge factors here.”

The result is an inversion of expectation: landscapes that still carry radioactive contamination, yet support apex predators and large herbivores at densities rarely tolerated in human-dominated Europe. Chernobyl sounds like a place where nothing big should live. Instead, big animals are among its most visible residents.

[...] If black frogs stretch our idea of adaptation, some of Chernobyl’s fungi push it even further.

Inside the ruined reactor buildings and across parts of the exclusion zone, scientists have found dark, melanin-rich fungi growing where almost nothing else can survive. They coat walls, creep across debris and colonise environments saturated with ionising radiation – even in places that should be profoundly hostile to life.

[....] Whether these fungi are truly ‘using’ radiation as an energy source remains an open question. What is clear is that they exploit an extreme niche that barely existed before 1986. When the reactor melted down, new ecological opportunities emerged for microbes able to tolerate conditions lethal to most life... (MORE - missing details)]]> https://www.sciencefocus.com/nature/5-se...-chernobyl

EXCERPTS: I first visited Chernobyl in 2016, 30 years after the explosion at Reactor Four. I expected silence and scarcity – a lifeless place, defined by radiation. Instead, I found beavers swimming beneath a nuclear power plant.

When the reactor exploded on 26 April 1986, many assumed the surrounding land would be biologically dead for generations. The exclusion zone – the area where radiation is highest and access is still restricted – covers roughly 2,600 km² on the Ukrainian side, about the size of Luxembourg.

When neighbouring areas of Belarus are included, the affected landscape stretches to more than 4,500 km². With that as a starting point, it was hard to imagine a future Chernobyl that was anything other than a wasteland.

In the days and months that followed, the evidence seemed to support that view. The pine forests closest to the plant absorbed such intense radiation that their needles turned an orange-red and died, creating what became known as the Red Forest. Early studies reported small mammals and invertebrates were disappearing in heavily contaminated areas.

And yet, 30 years on, there I was, watching dark heads cut slow arcs through the cooling ponds at the Chernobyl Nuclear Power Plant itself, beneath the vast concrete shell of reactor four. A glance upward reminded me this water had been engineered to keep a nuclear reactor from overheating. Now it held a functioning dam with beavers behaving like beavers.

Chernobyl’s mythology presents the place as being filled with grotesque mutations – two-headed fish and other monstrosities. Instead, a white-tailed eagle and a migrating osprey fished as if this were any other wetland.

Great white egrets worked the shallows in the reactor’s shadow. A grey wolf burst briefly from the reeds, then vanished again – running away, not patrolling some apocalyptic wasteland.

What people expect from Chernobyl is a catastrophe frozen in place: ruins, silence, and a landscape visibly broken.

Now, nearly 40 years on, the exclusion zone has become one of the most unusual ecological experiments on Earth, shaped not just by radiation but by abandonment and time. The usual ecological rules no longer apply, leading Chernobyl to have some truly weird wildlife.

Usually, large animals are the first to disappear after an environmental disaster. They reproduce slowly, require large territories, and are especially vulnerable to human pressure. But in Chernobyl, they’re thriving.

[...] And at first glance, it doesn’t appear that the radiation is bothering them. People often imagine Chernobyl’s wildlife is filled with monsters born of radiation, but scientists working in the zone are keen to reset those expectations.

Clear, dramatic physical deformities in large mammals are rarely documented because animals born with severe abnormalities rarely survive long enough to be observed. Meanwhile, the relatively short lifespans of wild mammals mean long-term effects are difficult to detect in the field.

The absence of monsters does not mean the absence of impact, of course, but it does mean that the impacts are not playing out in the ways popular culture expects. Instead, the decisive factor appears to be the sudden absence of people. Hunting stopped. Roads fell apart. Farming ceased. Human disturbance – often the most consistent pressure on large wildlife – dropped almost overnight.

“This matters,” says evolutionary biologist Germán Orizaola, who has been studying the effects of radiation in Chernobyl since the spring of 2016, “because if you focus on the species that are doing badly, you can blame radiation. But often the environment itself has changed. Ecology and the absence of humans are huge factors here.”

The result is an inversion of expectation: landscapes that still carry radioactive contamination, yet support apex predators and large herbivores at densities rarely tolerated in human-dominated Europe. Chernobyl sounds like a place where nothing big should live. Instead, big animals are among its most visible residents.

[...] If black frogs stretch our idea of adaptation, some of Chernobyl’s fungi push it even further.

Inside the ruined reactor buildings and across parts of the exclusion zone, scientists have found dark, melanin-rich fungi growing where almost nothing else can survive. They coat walls, creep across debris and colonise environments saturated with ionising radiation – even in places that should be profoundly hostile to life.

[....] Whether these fungi are truly ‘using’ radiation as an energy source remains an open question. What is clear is that they exploit an extreme niche that barely existed before 1986. When the reactor melted down, new ecological opportunities emerged for microbes able to tolerate conditions lethal to most life... (MORE - missing details)]]> <![CDATA[Are humans the only primates with white eyes? Why is that?]]> https://www.scivillage.com/thread-20032.html Mon, 23 Mar 2026 16:22:28 +0000 C C]]> https://www.scivillage.com/thread-20032.html https://www.forbes.com/sites/scotttraver...-explains/

INTRO: If you were to make eye contact with a chimpanzee, you’d likely notice something uncanny about them very quickly: you cannot easily tell where they’re looking. The tissue that surrounds their iris, known as the sclera, is dark brown or nearly black, which makes their gaze almost impossible to track.

Contrastingly, if you were to make eye contact with a friend or family member, you’d have no trouble instantly discerning the direction of their attention. Because human sclerae are bright white, our gaze is involuntarily legible; others can always tell, within a fraction of a second, exactly what we are focused on.

This, evolutionary biologists argue, is the product of hundreds of thousands of years of natural selection, which has sculpted the human eye into a highly precise social signaling instrument. Because of this selection, we are the only primates on Earth with uniformly white sclera. The larger question scientists have spent decades wrestling with is why.

The leading explanation for this unique exception comes from a theory known as the Cooperative Eye Hypothesis.

The hypothesis was initially formalized by Michael Tomasello and colleagues at the Max Planck Institute for Evolutionary Anthropology. Broadly, it proposes that human white sclera evolved specifically to make gaze direction visible to other humans. In turn, this would have enabled the kind of tight, wordless coordination that underpins almost all of our important social interactions, from raising children communally to building cities... (MORE - details)]]> https://www.forbes.com/sites/scotttraver...-explains/

INTRO: If you were to make eye contact with a chimpanzee, you’d likely notice something uncanny about them very quickly: you cannot easily tell where they’re looking. The tissue that surrounds their iris, known as the sclera, is dark brown or nearly black, which makes their gaze almost impossible to track.

Contrastingly, if you were to make eye contact with a friend or family member, you’d have no trouble instantly discerning the direction of their attention. Because human sclerae are bright white, our gaze is involuntarily legible; others can always tell, within a fraction of a second, exactly what we are focused on.

This, evolutionary biologists argue, is the product of hundreds of thousands of years of natural selection, which has sculpted the human eye into a highly precise social signaling instrument. Because of this selection, we are the only primates on Earth with uniformly white sclera. The larger question scientists have spent decades wrestling with is why.

The leading explanation for this unique exception comes from a theory known as the Cooperative Eye Hypothesis.

The hypothesis was initially formalized by Michael Tomasello and colleagues at the Max Planck Institute for Evolutionary Anthropology. Broadly, it proposes that human white sclera evolved specifically to make gaze direction visible to other humans. In turn, this would have enabled the kind of tight, wordless coordination that underpins almost all of our important social interactions, from raising children communally to building cities... (MORE - details)]]> <![CDATA[Why some birds seem to be developing a cigarette habit]]> https://www.scivillage.com/thread-20006.html Thu, 19 Mar 2026 16:44:45 +0000 C C]]> https://www.scivillage.com/thread-20006.html https://www.nytimes.com/2026/03/18/scien...=url-share

EXCERPTS: Darwin’s finches in the Galápagos, house finches in Mexico and song thrushes in New Zealand have all developed a curious habit: They put cigarette butts in their nests. Some songbirds in Britain are even nesting in outdoor ashtrays.

A new study adds evidence for why urban birds have picked up this preference, at least in one species: The toxins in tobacco may keep parasites at bay in the nests of blue tits, colorful birds that are found across Europe.

Cigarette butts contain about 4,000 chemical compounds, including nicotine, arsenic, polycyclic aromatic hydrocarbons and heavy metals. These compounds could ward off pests that harm birds and their offspring. The study was published this year in the journal Animal Behaviour.

Blue tits are cavity nesters, building nests in natural hollows or human-built boxes. Their nests are also prime habitat for bloodsucking parasites like ticks, fleas and blowflies that can exploit their captive targets — adults brooding eggs, and helpless nestlings.

So, when it came to cigarette butts and nesting in outdoor ashtrays, the researchers wanted to know whether blue tits could benefit from the pesticidal impacts of tobacco.

[...] The researchers in Mexico City have also shown that the impact of tobacco on nests isn’t limited to parasites. Dr. Suárez-Rodriguez showed that hatching, fledging and immune response in finch chicks improved alongside an increase in butts. But blood cells from nestlings showed evidence of genetic damage from cigarette butt exposure, with the long-term impacts unknown... (MORE - details)]]> https://www.nytimes.com/2026/03/18/scien...=url-share

EXCERPTS: Darwin’s finches in the Galápagos, house finches in Mexico and song thrushes in New Zealand have all developed a curious habit: They put cigarette butts in their nests. Some songbirds in Britain are even nesting in outdoor ashtrays.

A new study adds evidence for why urban birds have picked up this preference, at least in one species: The toxins in tobacco may keep parasites at bay in the nests of blue tits, colorful birds that are found across Europe.

Cigarette butts contain about 4,000 chemical compounds, including nicotine, arsenic, polycyclic aromatic hydrocarbons and heavy metals. These compounds could ward off pests that harm birds and their offspring. The study was published this year in the journal Animal Behaviour.

Blue tits are cavity nesters, building nests in natural hollows or human-built boxes. Their nests are also prime habitat for bloodsucking parasites like ticks, fleas and blowflies that can exploit their captive targets — adults brooding eggs, and helpless nestlings.

So, when it came to cigarette butts and nesting in outdoor ashtrays, the researchers wanted to know whether blue tits could benefit from the pesticidal impacts of tobacco.

[...] The researchers in Mexico City have also shown that the impact of tobacco on nests isn’t limited to parasites. Dr. Suárez-Rodriguez showed that hatching, fledging and immune response in finch chicks improved alongside an increase in butts. But blood cells from nestlings showed evidence of genetic damage from cigarette butt exposure, with the long-term impacts unknown... (MORE - details)]]> <![CDATA[Self-organizing neuronal connectivity]]> https://www.scivillage.com/thread-19954.html Thu, 12 Mar 2026 19:52:53 +0000 Magical Realist]]> https://www.scivillage.com/thread-19954.html
The research, published on January 17, 2024 in Nature Physics, accurately describes neuronal connectivity in a variety of model organisms and could apply to non-biological networks like social interactions as well.

“When you’re building simple models to explain biological data, you expect to get a good rough cut that fits some but not all scenarios,” said Stephanie Palmer, PhD, Associate Professor of Physics and Organismal Biology and Anatomy at UChicago and senior author of the paper. “You don’t expect it to work as well when you dig into the minutiae, but when we did that here, it ended up explaining things in a way that was really satisfying.”

Understanding how neurons connect

Neurons form an intricate web of connections between synapses to communicate and interact with each other. While the vast number of connections may seem random, networks of brain cells tend to be dominated by a small number of connections that are much stronger than most.

This “heavy-tailed” distribution of connections (so-called because of the way it looks when plotted on a graph) forms the backbone of circuitry that allows organisms to think, learn, communicate and move. Despite the importance of these strong connections, scientists were unsure if this heavy-tailed pattern arises because of biological processes specific to different organisms, or due to basic principles of network organization.

To answer these questions, Palmer and Christopher Lynn, PhD, Assistant Professor of Physics at Yale University, and Caroline Holmes, PhD, a postdoctoral researcher at Harvard University, analyzed connectomes, or maps of brain cell connections. The connectome data came from several different classic lab animals, including fruit flies, roundworms, marine worms and the mouse retina.

To understand how neurons form connections to one another, they developed a model based on Hebbian dynamics, a term coined by Canadian psychologist Donald Hebb in 1949 that essentially says, “neurons that fire together, wire together.” This means the more two neurons activate together, the stronger their connection becomes.

Across the board, the researchers found these Hebbian dynamics produce “heavy-tailed” connection strengths just like they saw in the different organisms. The results indicate that this kind of organization arises from general principles of networking, rather than something specific to the biology of fruit flies, mice, or worms.

The model also provided an unexpected explanation for another networking phenomenon called clustering, which describes the tendency of cells to link with other cells via connections they share. A good example of clustering occurs in social situations. If one person introduces a friend to a third person, those two people are more likely to become friends with them than if they met separately.

"These are mechanisms that everybody agrees are fundamentally going to happen in neuroscience,” Holmes said. “But we see here that if you treat the data carefully and quantitatively, it can give rise to all of these different effects in clustering and distributions, and then you see those things across all of these different organisms.”

Accounting for randomness

As Palmer pointed out, though, biology doesn’t always fit a neat and tidy explanation, and there is still plenty of randomness and noise involved in brain circuits. Neurons sometimes disconnect and rewire with each other — weak connections are pruned, and stronger connections can be formed elsewhere. This randomness provides a check on the kind of Hebbian organization the researchers found in this data, without which strong connections would grow to dominate the network.

The researchers tweaked their model to account for randomness, which improved its accuracy.

“Without that noise aspect, the model would fail,” Lynn said. “It wouldn’t produce anything that worked, which was surprising to us. It turns out you actually need to balance the Hebbian snowball effect with the randomness to get everything to look like real brains.”

Since these rules arise from general networking principles, the team hopes they can extend this work beyond the brain.

“That’s another cool aspect of this work: the way the science got done,” Palmer said. “The folks on this team have a huge diversity of knowledge, from theoretical physics and big data analysis to biochemical and evolutionary networks. We were focused on the brain here, but now we can talk about other types of networks in future work.”

The study, “Heavy–tailed neuronal connectivity arises from Hebbian self–organization,” was supported by the National Science Foundation, through the Center for the Physics of Biological Function (PHY–1734030) and a Graduate Research Fellowship (C.M.H.); by the James S. McDonnell Foundation through a Postdoctoral Fellowship Award (C.W.L.); and by the National Institutes of Health BRAIN initiative (R01EB026943)."

https://biologicalsciences.uchicago.edu/...ls-connect]]>
The research, published on January 17, 2024 in Nature Physics, accurately describes neuronal connectivity in a variety of model organisms and could apply to non-biological networks like social interactions as well.

“When you’re building simple models to explain biological data, you expect to get a good rough cut that fits some but not all scenarios,” said Stephanie Palmer, PhD, Associate Professor of Physics and Organismal Biology and Anatomy at UChicago and senior author of the paper. “You don’t expect it to work as well when you dig into the minutiae, but when we did that here, it ended up explaining things in a way that was really satisfying.”

Understanding how neurons connect

Neurons form an intricate web of connections between synapses to communicate and interact with each other. While the vast number of connections may seem random, networks of brain cells tend to be dominated by a small number of connections that are much stronger than most.

This “heavy-tailed” distribution of connections (so-called because of the way it looks when plotted on a graph) forms the backbone of circuitry that allows organisms to think, learn, communicate and move. Despite the importance of these strong connections, scientists were unsure if this heavy-tailed pattern arises because of biological processes specific to different organisms, or due to basic principles of network organization.

To answer these questions, Palmer and Christopher Lynn, PhD, Assistant Professor of Physics at Yale University, and Caroline Holmes, PhD, a postdoctoral researcher at Harvard University, analyzed connectomes, or maps of brain cell connections. The connectome data came from several different classic lab animals, including fruit flies, roundworms, marine worms and the mouse retina.

To understand how neurons form connections to one another, they developed a model based on Hebbian dynamics, a term coined by Canadian psychologist Donald Hebb in 1949 that essentially says, “neurons that fire together, wire together.” This means the more two neurons activate together, the stronger their connection becomes.

Across the board, the researchers found these Hebbian dynamics produce “heavy-tailed” connection strengths just like they saw in the different organisms. The results indicate that this kind of organization arises from general principles of networking, rather than something specific to the biology of fruit flies, mice, or worms.

The model also provided an unexpected explanation for another networking phenomenon called clustering, which describes the tendency of cells to link with other cells via connections they share. A good example of clustering occurs in social situations. If one person introduces a friend to a third person, those two people are more likely to become friends with them than if they met separately.

"These are mechanisms that everybody agrees are fundamentally going to happen in neuroscience,” Holmes said. “But we see here that if you treat the data carefully and quantitatively, it can give rise to all of these different effects in clustering and distributions, and then you see those things across all of these different organisms.”

Accounting for randomness

As Palmer pointed out, though, biology doesn’t always fit a neat and tidy explanation, and there is still plenty of randomness and noise involved in brain circuits. Neurons sometimes disconnect and rewire with each other — weak connections are pruned, and stronger connections can be formed elsewhere. This randomness provides a check on the kind of Hebbian organization the researchers found in this data, without which strong connections would grow to dominate the network.

The researchers tweaked their model to account for randomness, which improved its accuracy.

“Without that noise aspect, the model would fail,” Lynn said. “It wouldn’t produce anything that worked, which was surprising to us. It turns out you actually need to balance the Hebbian snowball effect with the randomness to get everything to look like real brains.”

Since these rules arise from general networking principles, the team hopes they can extend this work beyond the brain.

“That’s another cool aspect of this work: the way the science got done,” Palmer said. “The folks on this team have a huge diversity of knowledge, from theoretical physics and big data analysis to biochemical and evolutionary networks. We were focused on the brain here, but now we can talk about other types of networks in future work.”

The study, “Heavy–tailed neuronal connectivity arises from Hebbian self–organization,” was supported by the National Science Foundation, through the Center for the Physics of Biological Function (PHY–1734030) and a Graduate Research Fellowship (C.M.H.); by the James S. McDonnell Foundation through a Postdoctoral Fellowship Award (C.W.L.); and by the National Institutes of Health BRAIN initiative (R01EB026943)."

https://biologicalsciences.uchicago.edu/...ls-connect]]> <![CDATA[Self-organizing neuronal connectivity]]> https://www.scivillage.com/thread-19953.html Thu, 12 Mar 2026 19:51:21 +0000 Magical Realist]]> https://www.scivillage.com/thread-19953.html
The research, published on January 17, 2024 in Nature Physics, accurately describes neuronal connectivity in a variety of model organisms and could apply to non-biological networks like social interactions as well.

“When you’re building simple models to explain biological data, you expect to get a good rough cut that fits some but not all scenarios,” said Stephanie Palmer, PhD, Associate Professor of Physics and Organismal Biology and Anatomy at UChicago and senior author of the paper. “You don’t expect it to work as well when you dig into the minutiae, but when we did that here, it ended up explaining things in a way that was really satisfying.”

Understanding how neurons connect

Neurons form an intricate web of connections between synapses to communicate and interact with each other. While the vast number of connections may seem random, networks of brain cells tend to be dominated by a small number of connections that are much stronger than most.

This “heavy-tailed” distribution of connections (so-called because of the way it looks when plotted on a graph) forms the backbone of circuitry that allows organisms to think, learn, communicate and move. Despite the importance of these strong connections, scientists were unsure if this heavy-tailed pattern arises because of biological processes specific to different organisms, or due to basic principles of network organization.

To answer these questions, Palmer and Christopher Lynn, PhD, Assistant Professor of Physics at Yale University, and Caroline Holmes, PhD, a postdoctoral researcher at Harvard University, analyzed connectomes, or maps of brain cell connections. The connectome data came from several different classic lab animals, including fruit flies, roundworms, marine worms and the mouse retina.

To understand how neurons form connections to one another, they developed a model based on Hebbian dynamics, a term coined by Canadian psychologist Donald Hebb in 1949 that essentially says, “neurons that fire together, wire together.” This means the more two neurons activate together, the stronger their connection becomes.

Across the board, the researchers found these Hebbian dynamics produce “heavy-tailed” connection strengths just like they saw in the different organisms. The results indicate that this kind of organization arises from general principles of networking, rather than something specific to the biology of fruit flies, mice, or worms.

The model also provided an unexpected explanation for another networking phenomenon called clustering, which describes the tendency of cells to link with other cells via connections they share. A good example of clustering occurs in social situations. If one person introduces a friend to a third person, those two people are more likely to become friends with them than if they met separately.

"These are mechanisms that everybody agrees are fundamentally going to happen in neuroscience,” Holmes said. “But we see here that if you treat the data carefully and quantitatively, it can give rise to all of these different effects in clustering and distributions, and then you see those things across all of these different organisms.”

Accounting for randomness

As Palmer pointed out, though, biology doesn’t always fit a neat and tidy explanation, and there is still plenty of randomness and noise involved in brain circuits. Neurons sometimes disconnect and rewire with each other — weak connections are pruned, and stronger connections can be formed elsewhere. This randomness provides a check on the kind of Hebbian organization the researchers found in this data, without which strong connections would grow to dominate the network.

The researchers tweaked their model to account for randomness, which improved its accuracy.

“Without that noise aspect, the model would fail,” Lynn said. “It wouldn’t produce anything that worked, which was surprising to us. It turns out you actually need to balance the Hebbian snowball effect with the randomness to get everything to look like real brains.”

Since these rules arise from general networking principles, the team hopes they can extend this work beyond the brain.

“That’s another cool aspect of this work: the way the science got done,” Palmer said. “The folks on this team have a huge diversity of knowledge, from theoretical physics and big data analysis to biochemical and evolutionary networks. We were focused on the brain here, but now we can talk about other types of networks in future work.”

The study, “Heavy–tailed neuronal connectivity arises from Hebbian self–organization,” was supported by the National Science Foundation, through the Center for the Physics of Biological Function (PHY–1734030) and a Graduate Research Fellowship (C.M.H.); by the James S. McDonnell Foundation through a Postdoctoral Fellowship Award (C.W.L.); and by the National Institutes of Health BRAIN initiative (R01EB026943)."]]>
The research, published on January 17, 2024 in Nature Physics, accurately describes neuronal connectivity in a variety of model organisms and could apply to non-biological networks like social interactions as well.

“When you’re building simple models to explain biological data, you expect to get a good rough cut that fits some but not all scenarios,” said Stephanie Palmer, PhD, Associate Professor of Physics and Organismal Biology and Anatomy at UChicago and senior author of the paper. “You don’t expect it to work as well when you dig into the minutiae, but when we did that here, it ended up explaining things in a way that was really satisfying.”

Understanding how neurons connect

Neurons form an intricate web of connections between synapses to communicate and interact with each other. While the vast number of connections may seem random, networks of brain cells tend to be dominated by a small number of connections that are much stronger than most.

This “heavy-tailed” distribution of connections (so-called because of the way it looks when plotted on a graph) forms the backbone of circuitry that allows organisms to think, learn, communicate and move. Despite the importance of these strong connections, scientists were unsure if this heavy-tailed pattern arises because of biological processes specific to different organisms, or due to basic principles of network organization.

To answer these questions, Palmer and Christopher Lynn, PhD, Assistant Professor of Physics at Yale University, and Caroline Holmes, PhD, a postdoctoral researcher at Harvard University, analyzed connectomes, or maps of brain cell connections. The connectome data came from several different classic lab animals, including fruit flies, roundworms, marine worms and the mouse retina.

To understand how neurons form connections to one another, they developed a model based on Hebbian dynamics, a term coined by Canadian psychologist Donald Hebb in 1949 that essentially says, “neurons that fire together, wire together.” This means the more two neurons activate together, the stronger their connection becomes.

Across the board, the researchers found these Hebbian dynamics produce “heavy-tailed” connection strengths just like they saw in the different organisms. The results indicate that this kind of organization arises from general principles of networking, rather than something specific to the biology of fruit flies, mice, or worms.

The model also provided an unexpected explanation for another networking phenomenon called clustering, which describes the tendency of cells to link with other cells via connections they share. A good example of clustering occurs in social situations. If one person introduces a friend to a third person, those two people are more likely to become friends with them than if they met separately.

"These are mechanisms that everybody agrees are fundamentally going to happen in neuroscience,” Holmes said. “But we see here that if you treat the data carefully and quantitatively, it can give rise to all of these different effects in clustering and distributions, and then you see those things across all of these different organisms.”

Accounting for randomness

As Palmer pointed out, though, biology doesn’t always fit a neat and tidy explanation, and there is still plenty of randomness and noise involved in brain circuits. Neurons sometimes disconnect and rewire with each other — weak connections are pruned, and stronger connections can be formed elsewhere. This randomness provides a check on the kind of Hebbian organization the researchers found in this data, without which strong connections would grow to dominate the network.

The researchers tweaked their model to account for randomness, which improved its accuracy.

“Without that noise aspect, the model would fail,” Lynn said. “It wouldn’t produce anything that worked, which was surprising to us. It turns out you actually need to balance the Hebbian snowball effect with the randomness to get everything to look like real brains.”

Since these rules arise from general networking principles, the team hopes they can extend this work beyond the brain.

“That’s another cool aspect of this work: the way the science got done,” Palmer said. “The folks on this team have a huge diversity of knowledge, from theoretical physics and big data analysis to biochemical and evolutionary networks. We were focused on the brain here, but now we can talk about other types of networks in future work.”

The study, “Heavy–tailed neuronal connectivity arises from Hebbian self–organization,” was supported by the National Science Foundation, through the Center for the Physics of Biological Function (PHY–1734030) and a Graduate Research Fellowship (C.M.H.); by the James S. McDonnell Foundation through a Postdoctoral Fellowship Award (C.W.L.); and by the National Institutes of Health BRAIN initiative (R01EB026943)."]]> <![CDATA[Bird Flies 8,425 Miles from Alaska to Tasmania Non-Stop!]]> https://www.scivillage.com/thread-19929.html Mon, 09 Mar 2026 07:46:43 +0000 Yazata]]> https://www.scivillage.com/thread-19929.html
[Image: HC5111XXUAA0Ee6?format=jpg&name=small]
[Image: HC5111XXUAA0Ee6?format=jpg&name=small]



Quote:A migratory bird just shattered world records — flying 8,425 miles (13,560 km) NON-STOP across the Pacific without landing once.

The bar-tailed godwit doesn’t stop to eat, drink, or sleep during its migration across the Pacific Ocean. Its journey from Alaska to Australia takes roughly 11 days of continuous flight, covering over 13,000 kilometers through storms, headwinds, and open ocean with zero land beneath it the entire time.

Before departure, it does something almost surgical to its own body. It shrinks its digestive organs down to almost nothing, converting the stomach, intestines, and liver into raw fuel. The bird essentially eats its own gut to make room for fat reserves that will power its wings for nearly two weeks straight.

The brain doesn’t fully sleep either. Half of it stays active while the other half rests, alternating in shifts mid-flight at altitude over the open Pacific. The godwit is simultaneously unconscious and navigating with magnetic field sensitivity that no human instrument in the 18th century could replicate.

What makes this genuinely staggering beyond the physical record is the navigational precision involved. The bird leaves Alaska and arrives in New Zealand with accuracy that would embarrass early GPS systems. It reads Earth’s magnetic field, atmospheric pressure gradients, star positions, and potentially quantum-level compass mechanisms inside its eye that literally let it see magnetic field lines overlaid on its visual field.

Evolution spent millions of years building an aerospace navigation system inside a 300 gram animal.
]]>
[Image: HC5111XXUAA0Ee6?format=jpg&name=small]
[Image: HC5111XXUAA0Ee6?format=jpg&name=small]



Quote:A migratory bird just shattered world records — flying 8,425 miles (13,560 km) NON-STOP across the Pacific without landing once.

The bar-tailed godwit doesn’t stop to eat, drink, or sleep during its migration across the Pacific Ocean. Its journey from Alaska to Australia takes roughly 11 days of continuous flight, covering over 13,000 kilometers through storms, headwinds, and open ocean with zero land beneath it the entire time.

Before departure, it does something almost surgical to its own body. It shrinks its digestive organs down to almost nothing, converting the stomach, intestines, and liver into raw fuel. The bird essentially eats its own gut to make room for fat reserves that will power its wings for nearly two weeks straight.

The brain doesn’t fully sleep either. Half of it stays active while the other half rests, alternating in shifts mid-flight at altitude over the open Pacific. The godwit is simultaneously unconscious and navigating with magnetic field sensitivity that no human instrument in the 18th century could replicate.

What makes this genuinely staggering beyond the physical record is the navigational precision involved. The bird leaves Alaska and arrives in New Zealand with accuracy that would embarrass early GPS systems. It reads Earth’s magnetic field, atmospheric pressure gradients, star positions, and potentially quantum-level compass mechanisms inside its eye that literally let it see magnetic field lines overlaid on its visual field.

Evolution spent millions of years building an aerospace navigation system inside a 300 gram animal.
]]> <![CDATA[Epidemic of early puberty in the modern world: No single cause]]> https://www.scivillage.com/thread-19894.html Wed, 04 Mar 2026 17:37:58 +0000 C C]]> https://www.scivillage.com/thread-19894.html https://www.acsh.org/news/2026/03/02/pub...ance-49993

EXCERPTS: Few biological trends generate as much public anxiety as the perception that children are growing up too fast. Over the past century, the average age at which puberty begins has declined dramatically. Improvements in hygiene and nutrition are often cited to explain that decline. In recent decades, that pubertal shift has fueled concern that synthetic chemicals in our environment are disrupting children’s endocrine systems. The narrative is compelling: endocrine-disrupting chemicals (EDCs) interfere with hormonal signaling, puberty is hormonally driven, therefore chemicals must be accelerating development.

But biology rarely conforms to single-cause explanations.

Puberty is not triggered by a lone hormone or a single environmental exposure. It is the product of a tightly regulated neuroendocrine network integrating genetics, metabolic status, stress signaling, and environmental inputs. A large, longitudinal analysis from the Danish National Birth Cohort offers an opportunity to move beyond speculation and examine how these factors interact in real populations. Spoiler alert: as with most complex biological phenomena, the answer is less about one villain and more about competing signals within a delicately balanced system.

Understanding what is shifting the timing of puberty requires understanding how the reproductive axis works in the first place.

[...] The study investigated a range of potential causes of early puberty, including genetic factors, maternal lifestyle and dietary factors, maternal diseases and medication use that may result in prenatal exposure to EDCs, birth-related and postpartum events, children’s health and anthropometrics, and prenatal and early-life exposure to psychosocial factors.

[...] The Danish cohort data suggest that while endocrine-disrupting chemicals remain biologically plausible contributors, they are not the primary drivers detectable at the population level. Instead, inherited timing patterns, maternal smoking, psychosocial stress, and most consistently, childhood obesity emerge as more influential factors.

The modern environment does influence puberty. But the most powerful environmental signal may not be trace chemicals in plastics; it may be sustained caloric abundance and altered metabolic signaling in developing children. Biology, once again, resists simple narratives... (MORE - missing details)]]> https://www.acsh.org/news/2026/03/02/pub...ance-49993

EXCERPTS: Few biological trends generate as much public anxiety as the perception that children are growing up too fast. Over the past century, the average age at which puberty begins has declined dramatically. Improvements in hygiene and nutrition are often cited to explain that decline. In recent decades, that pubertal shift has fueled concern that synthetic chemicals in our environment are disrupting children’s endocrine systems. The narrative is compelling: endocrine-disrupting chemicals (EDCs) interfere with hormonal signaling, puberty is hormonally driven, therefore chemicals must be accelerating development.

But biology rarely conforms to single-cause explanations.

Puberty is not triggered by a lone hormone or a single environmental exposure. It is the product of a tightly regulated neuroendocrine network integrating genetics, metabolic status, stress signaling, and environmental inputs. A large, longitudinal analysis from the Danish National Birth Cohort offers an opportunity to move beyond speculation and examine how these factors interact in real populations. Spoiler alert: as with most complex biological phenomena, the answer is less about one villain and more about competing signals within a delicately balanced system.

Understanding what is shifting the timing of puberty requires understanding how the reproductive axis works in the first place.

[...] The study investigated a range of potential causes of early puberty, including genetic factors, maternal lifestyle and dietary factors, maternal diseases and medication use that may result in prenatal exposure to EDCs, birth-related and postpartum events, children’s health and anthropometrics, and prenatal and early-life exposure to psychosocial factors.

[...] The Danish cohort data suggest that while endocrine-disrupting chemicals remain biologically plausible contributors, they are not the primary drivers detectable at the population level. Instead, inherited timing patterns, maternal smoking, psychosocial stress, and most consistently, childhood obesity emerge as more influential factors.

The modern environment does influence puberty. But the most powerful environmental signal may not be trace chemicals in plastics; it may be sustained caloric abundance and altered metabolic signaling in developing children. Biology, once again, resists simple narratives... (MORE - missing details)]]> <![CDATA[Scared of spiders? The real horror story is a world without them]]> https://www.scivillage.com/thread-19880.html Mon, 02 Mar 2026 21:31:17 +0000 C C]]> https://www.scivillage.com/thread-19880.html https://www.eurekalert.org/news-releases/1118185

INTRO: Members of the arachnid class—think spiders, scorpions and harvestmen (daddy long legs)—are often the targets of revulsion, disgust and fear. Yet, they are crucial for ecosystems to thrive. Given the crash in worldwide biodiversity, including what some call the “insect apocalypse,” a pair of ecologists at the University of Massachusetts Amherst decided to check in on the general state of insects and arachnids in the U.S.—only to discover massive gaps in the data. Their research, published recently in PNAS, points to an urgent need to assess, protect and value insects and arachnids, a key pillar of planetary health.

“Insects and arachnids are fundamental for human society,” says Laura Figueroa, assistant professor of environmental conservation at UMass Amherst and the paper’s senior author. “They help with pollination and biological control of pests; they can serve as monitors of air and water quality, and they have worked their way deeply into many cultures throughout the world”— think of Aragog in the Harry Potter book series, for example. “Many people care about popular charismatic animals on the planet, like lions and pandas, which, justly, have received international conservation attention. Given that insects and arachnids don’t usually get the same attention, we wanted to know how they were doing.”

To assess the state of our creepier, crawlier neighbors, Figueroa and her graduate student, Wes Walsh, the paper’s lead author, gathered conservation assessments for the 99,312 known insect and arachnid species in North America, north of Mexico. What they discovered was astounding.

“Almost 90%—88.5% to be precise—of insect and arachnid species have no conservation status,” says Figueroa... (MORE - details, no ads)]]> https://www.eurekalert.org/news-releases/1118185

INTRO: Members of the arachnid class—think spiders, scorpions and harvestmen (daddy long legs)—are often the targets of revulsion, disgust and fear. Yet, they are crucial for ecosystems to thrive. Given the crash in worldwide biodiversity, including what some call the “insect apocalypse,” a pair of ecologists at the University of Massachusetts Amherst decided to check in on the general state of insects and arachnids in the U.S.—only to discover massive gaps in the data. Their research, published recently in PNAS, points to an urgent need to assess, protect and value insects and arachnids, a key pillar of planetary health.

“Insects and arachnids are fundamental for human society,” says Laura Figueroa, assistant professor of environmental conservation at UMass Amherst and the paper’s senior author. “They help with pollination and biological control of pests; they can serve as monitors of air and water quality, and they have worked their way deeply into many cultures throughout the world”— think of Aragog in the Harry Potter book series, for example. “Many people care about popular charismatic animals on the planet, like lions and pandas, which, justly, have received international conservation attention. Given that insects and arachnids don’t usually get the same attention, we wanted to know how they were doing.”

To assess the state of our creepier, crawlier neighbors, Figueroa and her graduate student, Wes Walsh, the paper’s lead author, gathered conservation assessments for the 99,312 known insect and arachnid species in North America, north of Mexico. What they discovered was astounding.

“Almost 90%—88.5% to be precise—of insect and arachnid species have no conservation status,” says Figueroa... (MORE - details, no ads)]]> <![CDATA[Could a vaccine prevent dementia? Shingles shot data only getting stronger.]]> https://www.scivillage.com/thread-19867.html Thu, 26 Feb 2026 23:44:00 +0000 C C]]> https://www.scivillage.com/thread-19867.html https://arstechnica.com/health/2026/02/c...-stronger/

INTRO: While lifesaving vaccines face a relentless onslaught from the Trump administration—with fervent anti-vaccine advocate Robert F. Kennedy Jr. leading the charge—scientific literature is building a wondrous story: A vaccine appears to prevent dementia, including Alzheimer’s, and may even slow biological aging.

For years, study after study has noted that older adults vaccinated against shingles seemed to have a lower risk of dementia. A study last month suggested the same vaccine appears to slow biological aging, including lowering markers of inflammation.

“Our study adds to a growing body of work suggesting that vaccines may play a role in healthy aging strategies beyond solely preventing acute illness,” study author Eileen Crimmins, of the University of Southern California, said.

Another study this month suggested the positive findings against dementia from the past may even be underestimates of the vaccination’s potential, with a newer vaccine against shingles providing even more protection.

If the dementia protection is real, it’s a fluke. The vaccine was designed for the entirely unrelated task of keeping the varicella-zoster virus—the cause of chickenpox (varicella)—from reactivating and causing an agonizing rash.. (MORE - details)]]> https://arstechnica.com/health/2026/02/c...-stronger/

INTRO: While lifesaving vaccines face a relentless onslaught from the Trump administration—with fervent anti-vaccine advocate Robert F. Kennedy Jr. leading the charge—scientific literature is building a wondrous story: A vaccine appears to prevent dementia, including Alzheimer’s, and may even slow biological aging.

For years, study after study has noted that older adults vaccinated against shingles seemed to have a lower risk of dementia. A study last month suggested the same vaccine appears to slow biological aging, including lowering markers of inflammation.

“Our study adds to a growing body of work suggesting that vaccines may play a role in healthy aging strategies beyond solely preventing acute illness,” study author Eileen Crimmins, of the University of Southern California, said.

Another study this month suggested the positive findings against dementia from the past may even be underestimates of the vaccination’s potential, with a newer vaccine against shingles providing even more protection.

If the dementia protection is real, it’s a fluke. The vaccine was designed for the entirely unrelated task of keeping the varicella-zoster virus—the cause of chickenpox (varicella)—from reactivating and causing an agonizing rash.. (MORE - details)]]> <![CDATA[A break in a longstanding mystery about origin of complex life]]> https://www.scivillage.com/thread-19825.html Thu, 19 Feb 2026 20:23:20 +0000 C C]]> https://www.scivillage.com/thread-19825.html https://www.eurekalert.org/news-releases/1116590

PRESS RELEASE: The most widely accepted scientific explanation for the arrival of all complex life on Earth has had an unsolved mystery at its heart. According to the theory, all plants, animals and fungi, known collectively as eukaryotes, are thought to have evolved after two very different types of microbes came together. The problem was in figuring out how the two were in such close proximity in the first place, given that one of the microbes requires oxygen for survival and the other was known to live in spaces without oxygen.

Now scientists from The University of Texas at Austin, publishing in the journal Nature, appear to have solved the mystery. One of our microbial ancestors was part of a group called the Asgard archaea, which today live primarily in the deep sea and other oxygen-free spaces. But according to the new study, some Asgards use, or at least tolerate oxygen. The discovery lends more credence to the idea that complex life evolved as the theory predicted—and apparently in an oxygen-rich environment.

“Most Asgards alive today have been found in environments without oxygen,” explained Brett Baker an associate professor of marine science and integrative biology at UT. “But it turns out that the ones most closely related to eukaryotes live in places with oxygen, such as shallow coastal sediments and floating in the water column, and they have a lot of metabolic pathways that use oxygen. That suggests that our eukaryotic ancestor likely had these processes, too.”

Baker and his team research Asgard archaea genomes, uncovering new lineages, expanding enzymatic diversity and exploring their metabolic pathways. The team’s latest finding agrees with the picture geologists and paleontologists have reconstructed of Earth’s history. Until about 1.7 billion years ago, Earth’s atmosphere had very little oxygen. Then, oxygen levels spiked dramatically, like levels seen today. Within a few hundred thousand years after this Great Oxidation Event, the first known microfossils of eukaryotes appeared, suggesting that the presence of oxygen might have been important for the origin of complex life.

“The fact that some of the Asgards, which are our ancestors, were able to use oxygen fits in with this very well,” Baker said. “Oxygen appeared in the environment, and Asgards adapted to that. They found an energetic advantage to using oxygen, and then they evolved into eukaryotes.”

Scientists believe eukaryotes arose when an Asgard archaeon developed a symbiotic relationship with an alphaproteobacterium. Eventually, they become one organism with the latter evolving to become an energy-producing organelle within eukaryotes called the mitochondria. In the new paper, the scientists vastly expand the number of Asgard archaea genomes and point to specific types of Asgard archaea, such as Heimdallarchaeia, which are closely related to eukaryotes but less common today.

“These Asgard archaea are often missed by low-coverage sequencing,” said co-author Kathryn Appler, a postdoctoral researcher at the Institut Pasteur in Paris, France. “The massive sequencing effort and layering of sequence and structural methods enabled us to see patterns that were not visible prior to this genomic expansion.” (MORE - details)]]> https://www.eurekalert.org/news-releases/1116590

PRESS RELEASE: The most widely accepted scientific explanation for the arrival of all complex life on Earth has had an unsolved mystery at its heart. According to the theory, all plants, animals and fungi, known collectively as eukaryotes, are thought to have evolved after two very different types of microbes came together. The problem was in figuring out how the two were in such close proximity in the first place, given that one of the microbes requires oxygen for survival and the other was known to live in spaces without oxygen.

Now scientists from The University of Texas at Austin, publishing in the journal Nature, appear to have solved the mystery. One of our microbial ancestors was part of a group called the Asgard archaea, which today live primarily in the deep sea and other oxygen-free spaces. But according to the new study, some Asgards use, or at least tolerate oxygen. The discovery lends more credence to the idea that complex life evolved as the theory predicted—and apparently in an oxygen-rich environment.

“Most Asgards alive today have been found in environments without oxygen,” explained Brett Baker an associate professor of marine science and integrative biology at UT. “But it turns out that the ones most closely related to eukaryotes live in places with oxygen, such as shallow coastal sediments and floating in the water column, and they have a lot of metabolic pathways that use oxygen. That suggests that our eukaryotic ancestor likely had these processes, too.”

Baker and his team research Asgard archaea genomes, uncovering new lineages, expanding enzymatic diversity and exploring their metabolic pathways. The team’s latest finding agrees with the picture geologists and paleontologists have reconstructed of Earth’s history. Until about 1.7 billion years ago, Earth’s atmosphere had very little oxygen. Then, oxygen levels spiked dramatically, like levels seen today. Within a few hundred thousand years after this Great Oxidation Event, the first known microfossils of eukaryotes appeared, suggesting that the presence of oxygen might have been important for the origin of complex life.

“The fact that some of the Asgards, which are our ancestors, were able to use oxygen fits in with this very well,” Baker said. “Oxygen appeared in the environment, and Asgards adapted to that. They found an energetic advantage to using oxygen, and then they evolved into eukaryotes.”

Scientists believe eukaryotes arose when an Asgard archaeon developed a symbiotic relationship with an alphaproteobacterium. Eventually, they become one organism with the latter evolving to become an energy-producing organelle within eukaryotes called the mitochondria. In the new paper, the scientists vastly expand the number of Asgard archaea genomes and point to specific types of Asgard archaea, such as Heimdallarchaeia, which are closely related to eukaryotes but less common today.

“These Asgard archaea are often missed by low-coverage sequencing,” said co-author Kathryn Appler, a postdoctoral researcher at the Institut Pasteur in Paris, France. “The massive sequencing effort and layering of sequence and structural methods enabled us to see patterns that were not visible prior to this genomic expansion.” (MORE - details)]]> <![CDATA[The Story of Evolution —How the Male and Female Sexes Originated ... —Male Nipples in]]> https://www.scivillage.com/thread-19803.html Tue, 17 Feb 2026 20:11:02 +0000 Mohsen Ezz El-Din Al-Bakri]]> https://www.scivillage.com/thread-19803.html Then a difference appeared between the gametes: some organisms began to produce large cells containing nutritional reserves — these later became eggs, and their ancestors became what we now call females. Other organisms produced small, fast-moving cells — these later became sperm, and their ancestors became what we now call males.
The large gametes are few in number, large in size, heavy, rich in nutrients, and precious for survival because they contain everything the offspring needs to survive after fusion. Their movement is very slow or almost nonexistent. The small gametes, on the other hand, are numerous, small in size, light, and fast-moving, but weak and unable to survive alone — they depend on the large gametes to complete the function of survival and reproduction. In short, the large one bets on quality and stability, while the small one bets on speed and quantity — and these two strategies are the origin of the division between male and female in nearly all sexually reproducing creatures.
At first, this was not a strict division; some organisms produced both types at once. Over time, specialization became highly beneficial, and the two evolutionary strategies became established: the “few, large, heavy, and valuable” strategy for the female, and the “many, small, light, and fast” strategy for the male. With time, these strategies evolved in most kingdoms that practice sexual reproduction — including algae, fungi, protists, fish, amphibians, and reptiles. In these multicellular organisms, a clear distinction between male and female began to appear: some individuals developed organs to produce large gametes and provide nourishment to offspring, while others developed organs to produce small gametes and transfer genetic material quickly. At this stage, a simple hormonal control appeared to regulate gamete production and reproductive functions.
Reptiles and birds branched off before mammals appeared; therefore, they retained only the basic skin glands and did not specialize in feeding the young. Among the ancestors of mammals, however, skin glands existed in both sexes in rows along the chest and abdomen for general purposes such as moisturizing, protecting eggs, or perhaps secreting substances or scents. Later, some of these glands evolved in females to secrete milk and feed the young. With this development, the rows were reduced to two central, functional glands for nursing in females, under the pressure of natural selection.
As for males, there was no selective pressure to preserve the old rows or to develop a nursing function. Thus occurred genetic streamlining — the elimination of unnecessary structures to reduce biological cost. Nevertheless, the original structural blueprint remained preserved in the genetic code, which is why they retain nipples with no function. In rare cases, more than two nipples can appear along what is known as the embryonic milk line — a condition called atavism, because it represents a temporary reappearance of an ancient ancestral trait.
These nipples exist in most male mammals, including cats, dogs, apes, and bats. In cats and dogs, the additional nipples or old glandular rows are often unnoticed because they are buried in thick fur — yet they exist anatomically. In some species such as horses and elephants, male nipples do not appear due to stronger embryonic suppression, but the structural origin of the glands still exists in the genetic code.
In multicellular embryos — now referring to mammals — the development of nipples begins in both male and female before sexual differentiation occurs. Then the sex hormones, such as testosterone in males, control the inhibition of breast tissue growth after the nipples have formed, which is why male nipples remain functionless.
In summary, the male and female were not two separate entities from the beginning, but gradually emerged from non-sexed unicellular forms. The difference between large and small gametes then evolved, followed by the emergence of specialized reproductive organs, then the evolution of mammary glands in mammals. Over time, evolution practiced genetic simplification, trimming away unnecessary ancestral structures in both males and females. What remains — the two nipples or their rare reappearance as atavism — is a trace of this long evolutionary history.
...
...
Regards,
always Giving
Mohsen]]> Then a difference appeared between the gametes: some organisms began to produce large cells containing nutritional reserves — these later became eggs, and their ancestors became what we now call females. Other organisms produced small, fast-moving cells — these later became sperm, and their ancestors became what we now call males.
The large gametes are few in number, large in size, heavy, rich in nutrients, and precious for survival because they contain everything the offspring needs to survive after fusion. Their movement is very slow or almost nonexistent. The small gametes, on the other hand, are numerous, small in size, light, and fast-moving, but weak and unable to survive alone — they depend on the large gametes to complete the function of survival and reproduction. In short, the large one bets on quality and stability, while the small one bets on speed and quantity — and these two strategies are the origin of the division between male and female in nearly all sexually reproducing creatures.
At first, this was not a strict division; some organisms produced both types at once. Over time, specialization became highly beneficial, and the two evolutionary strategies became established: the “few, large, heavy, and valuable” strategy for the female, and the “many, small, light, and fast” strategy for the male. With time, these strategies evolved in most kingdoms that practice sexual reproduction — including algae, fungi, protists, fish, amphibians, and reptiles. In these multicellular organisms, a clear distinction between male and female began to appear: some individuals developed organs to produce large gametes and provide nourishment to offspring, while others developed organs to produce small gametes and transfer genetic material quickly. At this stage, a simple hormonal control appeared to regulate gamete production and reproductive functions.
Reptiles and birds branched off before mammals appeared; therefore, they retained only the basic skin glands and did not specialize in feeding the young. Among the ancestors of mammals, however, skin glands existed in both sexes in rows along the chest and abdomen for general purposes such as moisturizing, protecting eggs, or perhaps secreting substances or scents. Later, some of these glands evolved in females to secrete milk and feed the young. With this development, the rows were reduced to two central, functional glands for nursing in females, under the pressure of natural selection.
As for males, there was no selective pressure to preserve the old rows or to develop a nursing function. Thus occurred genetic streamlining — the elimination of unnecessary structures to reduce biological cost. Nevertheless, the original structural blueprint remained preserved in the genetic code, which is why they retain nipples with no function. In rare cases, more than two nipples can appear along what is known as the embryonic milk line — a condition called atavism, because it represents a temporary reappearance of an ancient ancestral trait.
These nipples exist in most male mammals, including cats, dogs, apes, and bats. In cats and dogs, the additional nipples or old glandular rows are often unnoticed because they are buried in thick fur — yet they exist anatomically. In some species such as horses and elephants, male nipples do not appear due to stronger embryonic suppression, but the structural origin of the glands still exists in the genetic code.
In multicellular embryos — now referring to mammals — the development of nipples begins in both male and female before sexual differentiation occurs. Then the sex hormones, such as testosterone in males, control the inhibition of breast tissue growth after the nipples have formed, which is why male nipples remain functionless.
In summary, the male and female were not two separate entities from the beginning, but gradually emerged from non-sexed unicellular forms. The difference between large and small gametes then evolved, followed by the emergence of specialized reproductive organs, then the evolution of mammary glands in mammals. Over time, evolution practiced genetic simplification, trimming away unnecessary ancestral structures in both males and females. What remains — the two nipples or their rare reappearance as atavism — is a trace of this long evolutionary history.
...
...
Regards,
always Giving
Mohsen]]>