The model, which upends the decades-old “hard steps” theory that intelligent life was an incredibly improbable event, suggests that maybe it wasn’t all that hard or improbable. A team of researchers at Penn State, who led the work, said the new interpretation of humanity’s origin increases the probability of intelligent life elsewhere in the universe.

“This is a significant shift in how we think about the history of life,” said Jennifer Macalady, professor of geosciences at Penn State and co-author on the paper, which published today (Feb. 14) in the journal Science Advances. “It suggests that the evolution of complex life may be less about luck and more about the interplay between life and its environment, opening up exciting new avenues of research in our quest to understand our origins and our place in the universe.”

Initially developed by theoretical physicist Brandon Carter in 1983, the “hard steps” model argues that our evolutionary origin was highly unlikely due to the time it took for humans to evolve on Earth relative to the total lifespan of the sun — and therefore the likelihood of human-like beings beyond Earth is extremely low.

In the new study, a team of researchers that included astrophysicists and geobiologists argued that Earth’s environment was initially inhospitable to many forms of life, and that key evolutionary steps only became possible when the global environment reached a “permissive” state.

For example, complex animal life requires a certain level of oxygen in the atmosphere, so the oxygenation of Earth’s atmosphere through photosynthesizing microbes and bacteria was a natural evolutionary step for the planet, which created a window of opportunity for more recent life forms to develop, explained Dan Mills, postdoctoral researcher at The University of Munich and lead author on the paper.

“We’re arguing that intelligent life may not require a series of lucky breaks to exist,” said Mills, who worked in Macalady’s astrobiology lab at Penn State as an undergraduate researcher. “Humans didn’t evolve ‘early’ or ‘late’ in Earth’s history, but ‘on time,’ when the conditions were in place. Perhaps it’s only a matter of time, and maybe other planets are able to achieve these conditions more rapidly than Earth did, while other planets might take even longer.”

The central prediction of the “hard steps” theory states that very few, if any, other civilizations exist throughout the universe, because steps such as the origin of life, the development of complex cells and the emergence of human intelligence are improbable based on Carter’s interpretation of the sun’s total lifespan being 10 billion years, and the Earth’s age of around 5 billion years.

In the new study, the researchers proposed that the timing of human origins can be explained by the sequential opening of “windows of habitability” over Earth’s history, driven by changes in nutrient availability, sea surface temperature, ocean salinity levels and the amount of oxygen in the atmosphere. Given all the interplaying factors, they said, the Earth has only recently become hospitable to humanity — it’s simply the natural result of those conditions at work.

“We’re taking the view that rather than base our predictions on the lifespan of the sun, we should use a geological time scale, because that’s how long it takes for the atmosphere and landscape to change,” said Jason Wright, professor of astronomy and astrophysics at Penn State and co-author on the paper. “These are normal timescales on the Earth. If life evolves with the planet, then it will evolve on a planetary time scale at a planetary pace.”

Wright explained that part of the reason that the “hard steps” model has prevailed for so long is that it originated from his own discipline of astrophysics, which is the default field used to understand the formation of planets and celestial systems. The team’s paper is a collaboration between physicists and geobiologists, each learning from each other’s fields to develop a nuanced picture of how life evolves on a planet like Earth.

“This paper is the most generous act of interdisciplinary work,” said Macalady, who also directs Penn State’s Astrobiology Research Center. “Our fields were far apart, and we put them on the same page to get at this question of how we got here and are we alone? There was a gulf, and we built a bridge.”

The researchers said they plan to test their alternative model, including questioning the unique status of the proposed evolutionary “hard steps.” The recommended research projects are outlined in the current paper and include such work as searching the atmospheres of planets outside our solar system for biosignatures, like the presence of oxygen. The team also proposed testing the requirements for proposed “hard steps” to determine how hard they actually are by studying uni- and multicellular forms of life under specific environmental conditions such as lower oxygen and temperature levels.

Beyond the proposed projects, the team suggested the research community should investigate whether innovations — such as the origin of life, oxygenic photosynthesis, eukaryotic cells, animal multicellularity and Homo sapiens — are truly singular events in Earth’s history. Could similar innovations have evolved independently in the past, but evidence that they happened was lost due to extinction or other factors?

“This new perspective suggests that the emergence of intelligent life might not be such a long shot after all,” Wright said. “Instead of a series of improbable events, evolution may be more of a predictable process, unfolding as global conditions allow. Our framework applies not only to Earth, but also other planets, increasing the possibility that life similar to ours could exist elsewhere.”

The other co-author on the paper is Adam Frank of the University of Rochester. Penn State’s Astrobiology Research Center, the Penn State Center for Exoplanets and Habitable Worlds, the Penn State Extraterrestrial Intelligence Center, the NASA Exobiology program and the German Research Foundation supported this work.

Scientists at the Okinawa Institute of Science and Technology (OIST) and their international collaborators have discovered that anemonefish have evolved to maintain very low levels of sialic acid in their skin mucus to avoid triggering the release of nematocysts (stinging cells) in their sea anemone hosts. The researchers found that sea anemones also lack these sugar compounds in their own mucus, likely to avoid stinging themselves. Their findings, published in the journal BMC Biology, suggest anemonefish might be using a similar protective strategy to their hosts.

Comparing symbiotic and non-symbiotic species

The study combined multiple approaches, including glycobiology (the study of sugars) and transcriptomics — the study of all RNA molecules produced by an organism’s genome to understand gene expression and regulation. The researchers measured and analyzed mucus samples from both anemonefish and non-symbiotic damselfish species, using advanced techniques to separate and analyze the components of a mixture (liquid chromatography).

Sialic acids are important sugar molecules naturally present in most living organisms that play important roles in cellular processes such as cell-cell interactions and protein communication. Previous studies have shown that these molecules can trigger the release of sea anemone stinging cells. Very interestingly, scientists found that while anemonefish maintain certain levels of sialic acid in their internal organs like the brain and gut, they have specifically evolved to have very low levels in their protective mucus layer compared to non-symbiotic damselfish.

They also studied a unique case of the domino damselfish, which can live with anemones as juveniles. They found that these fish also show reduced sialic acid levels in their mucus during their juvenile stage, suggesting that different species have evolved similar adaptations for achieving symbiosis with sea anemones.

A particularly interesting finding was the correlation between sialic acid levels and the developmental stages of anemonefish. Young larvae, which are not yet ready to live with sea anemones, have normal sialic acid levels and get stung if they approach an anemone. However, when they metamorphose and develop their characteristic white stripes and bright orange coloring, their sialic acid levels drop, allowing them to safely enter the anemone.

“Our findings represent a major advancement because it’s one of the first studies to combine glycobiology with transcriptomic analysis to investigate this mechanism,” Dr. Natacha Roux, a researcher at Centre de Recherches Insulaires et Observatoire de l’Environnement (CRIOBE) and former researcher in OIST’s Computational Neuroethology Unit, elaborated.

Adapting for co-existence

The research team has two main hypotheses about how anemonefish maintain low sialic acid levels: either their mucus-producing cells express high levels of enzymes that cut sialic acid, or bacteria in their mucus microbiome are responsible for breaking it down. The second hypothesis is supported by previous observations that when anemonefish and sea anemones live together, their bacterial flora converge over time.

Prof. Vincent Laudet, head of OIST’s Marine Eco-Evo-Devo Unit emphasized that this is likely just one part of a complex symbiotic relationship. “Other factors might include the thickness of fish scales, the exchange of nutrients between species, and possible adjustments by the anemones themselves. The relationship is mutually beneficial, with anemonefish receiving protection from predators while helping to defend the anemone and providing nutritional benefits,” he said.

Future research aims to provide ultimate proof of this mechanism by attempting to manipulate the system — making anemonefish sensitive to anemone stings and non-symbiotic fish resistant. However, this is technically challenging and remains a work in progress. The study is also significant because it represents the first major paper from a new international research laboratory collaboration between France’s National Centre for Scientific Research (CNRS) and OIST.

Most cases are caused by a genetic mutation; Dravet syndrome in particular is most often caused by variants in the sodium channel gene SCN1A.

Recent research from Michigan Medicine takes aim at another variant in SCN1B, which causes an even more severe form of DEE.

Mice without the SCN1B gene experience seizures and 100 percent mortality just three weeks after birth.

Using mouse models, the investigative team, led by Chunling Chen, M.D., and Yukun Yuan, M.D., Ph.D., in the lab of Lori Isom, Ph.D., of the Department of Pharmacology at the Medical School, tested a gene therapy to replace SCN1B to increase the expression of beta-1 protein, which is necessary for the regulation of sodium channels in the brain.

Administering the therapy to newborn mice increased their survival, reduced the severity of their seizures and restored brain neuron excitability.

The team notes that different forms of SCN1B gene expression may result in different outcomes for the therapy.

However, the proof-of-concept is the first step toward a gene replacement therapy for SCN1B-linked developmental and epileptic encephalopathy.

“Intermittent fasting is known to have benefits, including boosting metabolism and helping with weight loss and heart disease. But until now, its potential side effects weren’t well understood,” says Alexander Bartelt, the Else Kröner Fresenius Professor and Chair of Translational Nutritional Medicine at TUM. In a recently published study, the team shows that intermittent fasting during adolescence could have long-term negative effects on metabolism.

Fasting improves metabolism in older mice, but not in the young

The researchers studied three groups of mice: adolescent, adult, and older animals. The mice remained without food for one day and were fed normally on two days. After ten weeks, insulin sensitivity improved in both the adult and older mice, meaning that their metabolism responded better to insulin produced by the pancreas. This is key to regulating blood sugar levels and preventing conditions like type 2 diabetes.

However, the adolescent mice showed a troubling decline in their beta cell function, the insulin-producing cells of the pancreas. Insufficient insulin production is linked to diabetes and disrupted metabolism. “Intermittent fasting is usually thought to benefit beta cells, so we were surprised to find that young mice produced less insulin after the extended fasting,” explains Leonardo Matta from Helmholtz Munich, one of the study’s lead authors.

Defective beta cells resemble those of type 1 diabetes patients

The researchers used the latest single-cell sequencing to uncover the cause of the beta cell impairment. By examining the blueprint of the pancreas, the team found that the beta cells in the younger mice failed to mature properly. “At some point, the cells in the adolescent mice stopped developing and produced less insulin,” says Peter Weber from Helmholtz Munich, also a lead author. Older mice, whose beta cells were already mature before the fasting began, remained unaffected.

The team compared their mouse findings to data from human tissues. They found that patients with type 1 diabetes, where beta cells are destroyed by an autoimmune response, showed similar signs of impaired cell maturation. This suggests that the findings from the mouse study could also be relevant to humans. “Our study confirms that intermittent fasting is beneficial for adults, but it might come with risks for children and teenagers,” says Stephan Herzig, a professor at TUM and director of the Institute for Diabetes and Cancer at Helmholtz Munich. “The next step is digging deeper into the molecular mechanisms underlying these observations. If we better understand how to promote healthy beta cell development, it will open new avenues for treating diabetes by restoring insulin production.”

The research shows that a higher concentration of copper in some pads is associated with increased harmful effects on sensitive cells from people’s lungs, as a result of particles being breathed in.

Exposure to pollution generated by cars, vans and lorries has long been linked to an increased risk of lung and heart disease. However, while past attention has mainly concentrated on exhaust emissions, particles are also released into the air from tyre, road and brake pad wear — emissions which are largely unregulated by legislation.

These ‘non-exhaust’ pollution sources are now responsible for the majority of vehicle particulate matter (PM) emissions in the UK and parts of Europe, with brake dust being the main contributor.

Lead author of the study, Dr James Parkin, explains that a move to electric cars is bringing the problem into sharper focus: “People generally associate pollution from cars as being from exhaust pipes and think of electric vehicles as having zero emissions. However, EVs still produce particulate matter due to friction and wear of the road, tyres, and brakes.

“We wanted to understand how different types of chemical composition of pads affect the toxicity of the particles emitted and what this might mean for the health of individuals.”

The scientists undertook an in-depth study examining the effects on lung health of PM from four different types of brake pad with differing chemical compositions; low metallic, semi-metallic, non-asbestos organic and hybrid-ceramic. The researchers were particularly interested in the smallest particles, of PM2.5 and below (often referred to as fine PM) — 30 times smaller than the diameter of a human hair.

These tiny particles can make their way beyond the upper airways and deeper into the delicate lung air sacs, which enable the exchange of oxygen and carbon dioxide to and from the blood stream. Fine PM from a variety of different sources is associated with over four million premature deaths per year worldwide.

Brake pad particulate matter was collected using specialist equipment. In the laboratory, the Southampton team used samples of cells from the lining of the lung and exposed them to the fine particulate matter to measure its effects, such as oxidative stress, inflammation, or the death of cells.

Results showed that of the four types of brake pads, non-asbestos organic pads were the most potent in terms of inducing inflammation and other markers of toxicity, and more toxic to human lung cells than diesel exhaust particles. Ceramic pads were the second most toxic. Importantly, both non-asbestos organic and ceramic pads contain high concentrations of copper, and later experiments to remove this copper found the PM became less toxic.

The findings, published in the journal Particle and Fibre Toxicology, suggest that a reduction of copper content in brake pads could help mitigate some of the harmful effects of vehicle particulate matter. Air pollution, including from cars, has been linked to a range of conditions, such as asthma, chronic obstructive pulmonary disease (COPD), cardiovascular diseases, dementia and idiopathic pulmonary fibrosis (scarring of the lung).

Project supervisor Professor Matthew Loxham comments: “This research has important implications for health and future policy because as we switch from diesel and petrol-powered cars to electric vehicles, non-exhaust particle emissions will remain. Non-exhaust emissions could increase over time due to electric vehicles being heavier than combustion engine vehicles and creating greater friction.”

The researchers highlight that while electric vehicles emit no exhaust emissions they aren’t emission-free and that health effects from vehicle emissions won’t necessarily be completely removed once the fleet is fully electrified. They suggest that current legislation, which focuses on PM exhaust emissions, may be inadequate to fully mitigate the health effects of vehicles in the future.

Dr Mathew Smith and Dr Georgios Dimitriadis from Lancaster University are both members of the Zwicky Transient Facility (ZTF), a wide-field sky astronomical survey using a new camera attached to the Samuel Oschin Telescope at Palomar Observatory in California.

Type Ia Supernovae are the dramatic explosions of white dwarf stars at the ends of their lives. Cosmologists use them to probe distances across the universe by comparing their fluxes, as further objects appear dimmer.

The ZTF cosmology science working group is today publishing twenty-one articles studying these 3628 Type Ia Supernovae, forming a Special Issue in Astronomy & Astrophysics.

Lancaster astrophysicist Dr Mathew Smith, co-leader of the ZTF SN Ia DR2 release, said: “This release provides a game-changing dataset for supernova cosmology. It opens the door to new discoveries about both the expansion of the universe and the fundamental physics of supernovae.”

This is the first time that astrophysicists have access to such a large and homogeneous dataset. Type Ia supernovae are rare, occurring approximately once per thousand years in a typical galaxy, but ZTF’s depth and survey strategy enable researchers to detect nearly four per night. In only two and a half years, ZTF has doubled the number available Type Ia Supernovae for cosmology acquired for the last 30 years to almost three thousand.

Head of the ZTF Cosmology Science working group Dr Mickael Rigault from the Institut des deux Infinis de Lyon (CNRS / Claude Bernard University) said: “”For the past five years, a group of thirty experts from around the world have collected, compiled, assembled, and analysed these data. We are now releasing it to the entire community. This sample is so unique in terms of size and homogeneity, that we expect it to significantly impact the field of Supernovae cosmology and to lead to many additional new discoveries in addition to results we have already published.”

The ZTF camera, installed on the 48-inch Schmidt telescope at Palomar Observatory, scans the entire northern sky daily in three optical bands, reaching a depth of 20.5 magnitude — one million times fainter than the dimmest stars visible to the naked eye. This sensitivity allows ZTF to detect nearly all supernovae within 1.5 billion light-years of Earth.

Professor Kate Maguire from Trinity College Dublin, a co-author of the study, said: “Thanks to ZTF’s unique ability to scan the sky rapidly and deeply, we have captured multiple supernovae within days — or even hours — of explosion, providing novel constraints on how they end their lives.”

The acceleration of the expansion of the Universe, awarded by the Nobel prize in 2011, was discovered in the late 90s using approximately a hundred of these Supernovae. Since then, cosmologists are investigating the reason for this acceleration caused by the dark energy that plays the role of an anti-gravity force across the Universe.

Co-author Professor Ariel Goobar, Director of the Oskar Klein Centre in Stockholm, one of the founding institutions of ZTF, and also member of the team that discovered the accelerated expansion of the Universe in 1998 said: “Ultimately, the aim is to address one of our time’s biggest questions in fundamental physics and cosmology, namely what is most of the Universe made of? For that we need the ZTF supernova data.”

One of the key outcomes of these studies is that Type Ia Supernovae intrinsically vary as a function of their host environment, more so than expected before, and the correction mechanism assumed so far has to be revisited. This could change how we measure the expansion history of the Universe and may have important consequences for current deviation observed in the standard model of cosmology.

Dr Rigault said: “With this large and homogeneous dataset, we can explore Type Ia supernovae with an unprecedented level of precision and accuracy. This is a crucial step toward honing the use of Type Ia Supernovae in cosmology and assess if current deviations in cosmology are due to new fundamental physics or unknown problem in the way we derive distances.”

The study — led by the University of Exeter and the Ascension Island Government — examined three seamounts off Ascension Island in the South Atlantic Ocean.

Two were shallow seamounts, with peaks less than 100 metres below the surface — and these were teeming with vast numbers of predators, including sharks and tuna.

“Seamounts have been likened to oases of life in the comparative deserts of the open ocean,” said Dr Sam Weber, from the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

“However, this hasn’t been studied in detail — meaning we’ve been unsure about why seamounts attract so many marine top predators.”

Some seamounts create upwellings of minerals that support bountiful phytoplankton (tiny drifting plants that are the first link in ocean food chains).

Such quantities of phytoplankton can support increased numbers of other species, from zooplankton (which eat phytoplankton) all the way to top predators like sharks.

But this study found no evidence of increased “primary productivity” of phytoplankton at the Ascension seamounts.

Instead, enrichment of marine life (measured by “biomass” — the total weight of organic material) goes up with each level of the food web.

Zooplankton were twice as common at shallow seamounts than in the open ocean, while shark biomass was 41 times higher.

“Our findings suggest that several factors combine to make seamounts so rich in sea life, especially predators,” Dr Weber said.

“While primary productivity is not higher at the seamounts we studied, filter feeders may benefit from prey being ‘blown over’ the peak, and the peak may also stop prey species from retreating into deeper water to avoid predators. This effectively concentrates food in one predictable spot in the ocean.

“Also, some predators appear to use seamounts as ‘hubs’ to gather, socialise, mate or rest, and as a base to return to after hunting in the open ocean. This may lead to more top predators on seamounts than you would expect based on the amount of food available.”

The findings suggest certain species tend to gather at seamounts — including Galapagos and silky sharks, and yellowfin and bigeye tuna.

Some individual animals were found to be “resident” — living at a particular seamount most of the time — and others visited both shallow seamounts in the study (80km apart).

The study also found a “halo” of increased marine life around seamounts, extending at least 5km into the open ocean.

The seamounts in the study are all within the Ascension Island Marine Protected Area — a 445,000 square km zone where no large-scale commercial fishing or seabed mining are allowed.

“Our results reinforce the conservation significance of shallow seamounts for many top predators,” Dr Weber said.

“This research also offers fundamental insights into seamounts’ role as activity hubs and oases for marine species and shows how these remarkable habitats influence the oceans that surround them.”

Data for the study was collected by a National Geographic Pristine Seas expedition aboard the British Antarctic Survey research vessel RRS James Clark Ross

The research was funded by a European Union BEST grant and the UK government’s Darwin Initiative.

The play-like behaviour of the flies described by the researchers, involving voluntary passive movements such as swinging, bobbing, sliding or turning, has now been demonstrated in insects for the first time. “This could help us to find out how we humans also develop efficient self-awareness of our bodies,” explains Huetteroth, whose study was funded by the German Research Foundation (DFG).

In collaboration with Northumbria University, the researchers conducted a detailed analysis of how the flies interacted with the carousel. While many flies avoided the carousel, others visited it repeatedly and for long periods. When two carousels rotated alternately, the flies even actively followed the stimulation.

The scientists placed a total of 190 individual flies in a carousel arena, a glass dome about one centimetre high, and then filmed them for 3 to 14 days. The positions of the flies in the recordings were then automatically recognised and tracked using special software. Only a fraction of the data generated was included in the study. “Using several carousels, we generated and analysed a total of around seven years of film data,” says Dr Tilman Triphan, the first author of the study. This effort was necessary because, unlike most behavioural experiments on flies, the researchers had to rely on the insects’ voluntary behaviour. There was not enough space under the glass dome for the flies to fly onto the carousel. “However, we were able to distinguish whether the flies had deliberately walked onto the carousel or jumped onto it in an uncoordinated way. This allowed us to show that unplanned visits to the carousel were rather atypical for the playing flies,” says co-author Dr Clara H. Ferreira, an assistant Professor at Northumbria University.

According to Huetteroth, the findings will now allow a detailed investigation of the underlying genetic, neuronal and biochemical factors that influence the fruit fly’s playful behaviour and the benefits this has for playful creatures in general.

Cocoa (Theobroma cacao L.) is a vital cash-crop for four to six million small-holder farmers across the tropics, and supports a global chocolate industry valued at over USD 100 billion annually. The combination of millions of farmers relying on cocoa for their livelihoods, and increasing global demand for the crop, has driven cocoa plantation expansion and intensification of farming practices, often at the expense of biodiversity and long-term sustainability.

A new research study led by the University of Oxford, in collaboration with Westlake University, China, Universidade Estadual de Santa Cruz, Brazil, and University of Göttingen, Germany, has highlighted the significant risks posed to cocoa production by climate change. However, the authors also identified farm management solutions that can both climate-proof cocoa crops and boost productivity without the need to expand plantations into forests.

The research, conducted across three major cocoa-producing countries — Brazil, Ghana, and Indonesia, which together account for 33% of global cocoa production — investigated key factors influencing cocoa yields. The findings revealed that increasing pollination rates above current levels could boost yields by 20%. This demonstrates that insufficient pollination is occurring to produce the maximum possible yield for many cocoa plantations. Separate to the impact of pollination, sites where temperatures were up to 7 degrees warmer had 20-31% lower cocoa yields, underscoring the vulnerability of cocoa-producing regions to the effects of climate change.

Co-author Dr Acheampong Atta-Boateng, who recently completed his doctoral work at the University of Oxford, said: ‘Cocoa is pollinated by tiny insects such as midges and thrips, and it comes as quite a surprise that most of the time there simply isn’t enough pollination happening to produce the cocoa crop that is possible.’

To support sustainable cocoa production, researchers recommend practical strategies to enhance pollination, such as maintaining leaf litter and other understory biomass, preserving soil organic matter, providing moderate shade, and reducing agricultural chemical use. These practices not only increase pollinator abundance, but also help regulate plantation temperatures and improve soil health, ensuring long-term plantation resilience.

Dr Tonya Lander, from the University of Oxford and first author of the study said: ‘This research shows that sustainable agricultural methods can significantly improve cocoa yields without farm expansion or intensification. By adopting biodiversity-centred, climate-resilient farming techniques, the cocoa sector can both increase production and safeguard farmers’ livelihoods.’

Dr Tom Wanger of Westlake University, China added: ‘The rising demand for cocoa and the short-term economic benefits to farmers has led to plantation expansion and ecological homogenization at the expense of biodiversity and vital ecosystem services, like pollination. This study highlights the long-term risks of this approach, and how pollination can be a solution that works alongside climate-resilient agricultural systems to achieve long-term, ecologically and financially sustainable solutions.’