Early human ancestors used their hands to both climb trees and make tools, new study shows
WASHINGTON (AP) — Our hands can reveal a lot about how a person has lived – and that's true for early human ancestors, too.
Different activities such as climbing, grasping or hammering place stress on different parts of our fingers. In response to repeated stress, our bones tend to thicken in those areas.
To study how ancient humans used their hands, scientists used 3D scanning to measure and analyze the bone thickness of fingers.
They focused on the fossil hands of two early human ancestor species recovered from excavations in southern Africa, called Australopithecus sediba and Homo naledi. The individuals lived around 2 million years ago and around 300,000 years ago, respectively.
Both ancient human species showed signs of simultaneously using their hands to move around – such as by climbing trees – as well as to grasp and manipulate objects, a requirement to being able to make tools.
'They were likely walking on two feet and using their hands to manipulate objects or tools, but also spent time climbing and hanging,' perhaps on trees or cliffs, said study co-author and paleoanthropologist Samar Syeda of the American Museum of Natural History.
The research was published Wednesday in Science Advances.
The findings show there wasn't a simple 'evolution in hand function where you start off with more 'ape-like' and end up more 'human-like,'' said Smithsonian paleoanthropologist Rick Potts, who was not involved in the study.
Complete fossil hands are relatively rare, but the specimens used in the study gave an opportunity to understand the relative forces on each finger, said Chatham University paleontologist Erin Marie Williams-Hatala, who was not involved in the study.
'Hands are one of the primary ways we engage with world around us,' she said.
___
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Science and Educational Media Group and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
7 hours ago
- Yahoo
Astronomy show accidentally reveals unseen structure in our solar system
An accidental discovery might change how we think about one of the most mysterious structures in our solar system. The Oort Cloud, a large expanse of icy bodies revolving around the sun at a distance 1,000 times greater than the orbit of Neptune, is widely thought to be spherical — although it has never been directly observed. But during the preproduction of a show titled 'Encounters in the Milky Way,' which debuted Monday at the Hayden Planetarium in New York City, a projection on the planetarium's dome revealed something strange within the Oort Cloud: a spiral. The curators were testing out a scene in September that includes a detailed view of Earth's celestial neighborhood — from the sun to the solar system's outer edges — and were surprised when they saw the structure, which looked coincidentally similar to a spiral galaxy such as our own. 'We hit play on the scene, and immediately we saw it. It was just there,' recalled Jackie Faherty, an astrophysicist at the American Museum of Natural History and the curator of the show. 'I was confused and thought that was super weird. I didn't know if it was an artifact, I didn't know if it was real.' To investigate, Faherty got in touch with David Nesvorny, an institute scientist with the Southwest Research Institute in Boulder, Colorado, and the Oort Cloud expert who had provided scientific data for the scene. 'We didn't create it — David did,' Faherty said. 'This is David's simulation, and it's grounded in physics. It has a totally good physical explanation for why it should be there.' At first, Nesvorny suspected artifacts — abnormalities or distortions in the data visualization — but once he looked at his data, he confirmed the presence of the spiral and eventually published a scientific paper about the discovery in April in The Astrophysical Journal. 'Weird way to discover things,' he said. 'I should know my data better, after years of working with it.' The existence of the Oort Cloud was first proposed in 1950 by Dutch astronomer Jan Oort, who imagined it as a shell of icy bodies swirling around the sun from up to 1.5 light-years away. The cloud is the most distant region in our solar system, stretching as much as halfway to the next star, according to NASA. It's composed of leftovers from the making of our solar system, which were scattered in every direction by the planets after they formed. That means many of the icy bodies in the Oort Cloud don't share the same orbital plane as the solar system itself but travel at various inclinations, which is why the Oort Cloud is pictured as a sphere. If one of those icy bodies gets flung inward toward the sun, the heat starts vaporizing some of the material in the body, creating a tail — and what we call a comet. 'Every now and again, some of these icy bodies come into the inner solar system, and we can see the orbit that they're on,' Faherty said. 'And they're on these really crazy, long orbits. It can take them millions of years to go around the sun. And when they come in, they help us understand how far away they may have come from.' The problem with trying to imagine what the Oort Cloud looks like is that scientists have never seen it, even though we are technically surrounded by it. That's because the bodies that make it up are small — fewer than 60 miles (97 kilometers) in diameter — and even though they potentially number in the trillions, they are far away, making observations with telescopes difficult. The spiral was hiding in Nesvorny's data because he had never thought of visualizing it three-dimensionally. 'I never looked at it in Cartesian coordinates — I didn't have a good reason to do so,' he said. 'But once you do that, it's obvious. It's there.' To confirm the findings, Nesvorny used one of the most powerful computers in the world, NASA's Pleiades Supercomputer, to run simulations that took weeks to complete. 'I thought, maybe just this particular simulation (I gave the planetarium) is showing it, and all the other simulations with other stellar encounters, other parameters, will not show it, in which case it wouldn't be so interesting,' he said. 'But all the simulations, all the models I have, show the spiral.' The reason it's there, he said, is that objects in the Oort Cloud are far away enough from the sun's gravity that they also start being affected by the galactic tide — the gravitational field of our galaxy, exerted by the stars and the dark matter in it. This field is acting on the small bodies and comets in the Oort Cloud by twisting their orbital planes to create a spiral. The spiral, Nesvorny added, is in the inner part of the Oort Cloud, the closest to us, and he still believes that the outer portion is spherical or shell-shaped. The problem of observing the Oort Cloud remains, even though the Vera C. Rubin Observatory, a powerful telescope that recently came online in Chile, could offer a hand by discovering and observing individual icy bodies in the cloud. However, according to Nesvorny, the telescope will likely discover dozens of these bodies — not the hundreds that would be required to produce a meaningful visualization of the spiral. The spiral theory helps to illuminate the dynamics of our solar system, according to Faherty. 'If you're going to come up with a theory of how solar systems evolve, you should take into account the kind of shapes you might have in their structure,' she said. 'Maybe comets helped deliver water to Earth. Maybe the building blocks of life could be out there in the Oort Cloud, so if you want to talk about the potential building blocks of life that surround our solar system, you need to understand its shape.' It's a 'dream,' she added, to be able to present science so recent in a show aimed at the general public. 'I truly believe that the planetarium, the dome itself, is a research tool,' Faherty said. 'I like to say that this is science that hasn't had time to reach your textbook yet.' The spiral finding is a wonderful example of just how much we can learn through visualizing the universe in new ways, said Malena Rice, an assistant professor of astronomy at Yale University who did not participate in the study. 'This result reshapes our mental image of our home solar system, while also providing a new sense for what extrasolar systems' Oort clouds may look like,' Rice added. 'It unites our models of the solar system with what we know about the broader galaxy, placing it into context as a dynamic system. We are not static, and we are not isolated — our solar system is shaped by its broader ecosystem, and the Oort spiral exemplifies that.' While the paper is interesting, it is almost entirely theoretical, as it is based on numerical simulations of the interactions between the sun's gravity and the gravitational pull of the rest of the Milky Way galaxy's motion, said Edward Gomez, an astrophysicist and honorary lecturer at Cardiff University in the UK. He also was not involved with the study. 'Long period comets enter the inner solar system at a range of angles, which the authors try to model using their spiral arm idea,' Gomez said in an email. 'What they are proposing could be true, but it could also be modelled by other shapes of the Oort cloud or physical processes. How to test this is their major issue, because only a handful of potential Oort cloud objects are known about.' Confirming the findings will be a challenge, noted Simon Portegies Zwart, a professor of numerical star dynamics at Leiden University in the Netherlands who was not part of the team behind the research. 'It is interesting that they found the spiral, (but) it seems unlikely that we are going to witness (it) in the foreseeable future,' he said. With luck, he added, the Vera Rubin observatory will detect a few hundred inner Oort Cloud objects, but the spiral would only be visible if many more are found: 'It therefore seems unlikely to be a clearly detectable structure.'
Hamilton Spectator
7 hours ago
- Hamilton Spectator
Chesapeake Bay health grade dips after hottest year on record and extreme rainfall patterns
ANNAPOLIS, Md. (AP) — The health of the Chesapeake Bay declined in an annual report card on the nation's largest estuary released Tuesday, with scientists noting the effect of extreme rainfall patterns during the hottest year on record. The University of Maryland Center for Environmental Science gave the bay a C grade in its report card. That compares to a C-plus grade the bay received last year , which was the highest grade it had received since 2002. 'There was a substantial upturn in the overall Bay Health score in 2024, and it came down a little this year,' said Heath Kelsey, director of UMCES Integration and Application Network. 'Over the long term, though, there is still an improving trend from the 1980s until now. We think extreme weather may have had some impact on the scores this year.' The report noted that last year was the hottest year on record , with extreme rainfall patterns. 'While parts of the watershed experienced drought, brief but intense downpours can cause water to flow over the ground rather than soak into it, increasing the fertilizer, dirt, and debris carried into waterways,' the report said. Bill Dennison, vice president for Science Application at UMCES, said the changing climate is definitely having an effect on the bay. 'One of the things that we saw in Maryland, in particular, was a prolonged summer drought — not so much spring, but a summer drought — punctuated by these extreme runoff events,' Dennison said. 'So what was happening was that the crops didn't have enough water, so they're not soaking up the nutrients.' As a result, when it did rain, there were excess nutrients, like nitrogen and phosphorus, that were flowing into the bay, Dennison said. 'Now sadly, this is kind of our future,' Dennison said at a news conference at the Annapolis Maritime Museum near the bay. 'This is the kind of weather patterns that are starting to become more common, which is drought punctuated by extreme events.' Warmer weather winters and higher temperatures mean less oxygen in the water for aquatic life, stressing fish and shellfish, Dennison added. 'So these are some of the things that we have to overcome and build more resilience into our system,' Dennison said. Despite the grade drop, the report cited long-term improvements in dissolved oxygen in the bay's waters. That's the amount of oxygen present in the water that is needed to support bay aquatic life. The report also noted long-term improvements in aquatic grasses, which provide habitat and food for various species, improve water quality and protect shorelines from erosion. Phosphorus and nitrogen levels also have improved in the long-term in another positive sign. While they are needed by the bay's organisms, excessive nitrogen and phosphorus degrade the bay's water quality. Excess nitrogen and phosphorus fuel algal blooms that can cloud the water and block sunlight from reaching underwater grasses. Water clarity and chlorophyll-a scores, however, have declining long-term trends, the report said. Chlorophyll-a in the bay is an indicator of phytoplankton abundance and water quality. Improving trends can be attributed to management and restoration efforts at the regional, state, and local levels, the report said. Regionally, wastewater treatment plants have been upgraded and programs have been put in place to reduce nutrient and sediment input. The health of the bay is a reflection of what's happening across its six-state watershed, which includes Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia along with the District of Columbia. UMCES, which is marking its 100th anniversary, also provides a grade for the overall watershed health in its report card. It gave the watershed a grade of C-plus. The watershed health grade includes ecological, societal and economic indicators. The most concerning societal indicator was heat vulnerability, the report said, noting communities may be under heat stress due to hotter air temperatures, less tree canopy cover, and more paved surfaces.
CNN
7 hours ago
- CNN
Astronomy show accidentally reveals unseen structure in our solar system
An accidental discovery might change how we think about one of the most mysterious structures in our solar system. The Oort Cloud, a large expanse of icy bodies revolving around the sun at a distance 1,000 times greater than the orbit of Neptune, is widely thought to be spherical — although it has never been directly observed. But during the preproduction of a show titled 'Encounters in the Milky Way,' which debuted Monday at the Hayden Planetarium in New York City, a projection on the planetarium's dome revealed something strange within the Oort Cloud: a spiral. The curators were testing out a scene in September that includes a detailed view of Earth's celestial neighborhood — from the sun to the solar system's outer edges — and were surprised when they saw the structure, which looked coincidentally similar to a spiral galaxy such as our own. 'We hit play on the scene, and immediately we saw it. It was just there,' recalled Jackie Faherty, an astrophysicist at the American Museum of Natural History and the curator of the show. 'I was confused and thought that was super weird. I didn't know if it was an artifact, I didn't know if it was real.' To investigate, Faherty got in touch with David Nesvorny, an institute scientist with the Southwest Research Institute in Boulder, Colorado, and the Oort Cloud expert who had provided scientific data for the scene. 'We didn't create it — David did,' Faherty said. 'This is David's simulation, and it's grounded in physics. It has a totally good physical explanation for why it should be there.' At first, Nesvorny suspected artifacts — abnormalities or distortions in the data visualization — but once he looked at his data, he confirmed the presence of the spiral and eventually published a scientific paper about the discovery in April in The Astrophysical Journal. 'Weird way to discover things,' he said. 'I should know my data better, after years of working with it.' The existence of the Oort Cloud was first proposed in 1950 by Dutch astronomer Jan Oort, who imagined it as a shell of icy bodies swirling around the sun from up to 1.5 light-years away. The cloud is the most distant region in our solar system, stretching as much as halfway to the next star, according to NASA. It's composed of leftovers from the making of our solar system, which were scattered in every direction by the planets after they formed. That means many of the icy bodies in the Oort Cloud don't share the same orbital plane as the solar system itself but travel at various inclinations, which is why the Oort Cloud is pictured as a sphere. If one of those icy bodies gets flung inward toward the sun, the heat starts vaporizing some of the material in the body, creating a tail — and what we call a comet. 'Every now and again, some of these icy bodies come into the inner solar system, and we can see the orbit that they're on,' Faherty said. 'And they're on these really crazy, long orbits. It can take them millions of years to go around the sun. And when they come in, they help us understand how far away they may have come from.' The problem with trying to imagine what the Oort Cloud looks like is that scientists have never seen it, even though we are technically surrounded by it. That's because the bodies that make it up are small — fewer than 60 miles (97 kilometers) in diameter — and even though they potentially number in the trillions, they are far away, making observations with telescopes difficult. The spiral was hiding in Nesvorny's data because he had never thought of visualizing it three-dimensionally. 'I never looked at it in Cartesian coordinates — I didn't have a good reason to do so,' he said. 'But once you do that, it's obvious. It's there.' To confirm the findings, Nesvorny used one of the most powerful computers in the world, NASA's Pleiades Supercomputer, to run simulations that took weeks to complete. 'I thought, maybe just this particular simulation (I gave the planetarium) is showing it, and all the other simulations with other stellar encounters, other parameters, will not show it, in which case it wouldn't be so interesting,' he said. 'But all the simulations, all the models I have, show the spiral.' The reason it's there, he said, is that objects in the Oort Cloud are far away enough from the sun's gravity that they also start being affected by the galactic tide — the gravitational field of our galaxy, exerted by the stars and the dark matter in it. This field is acting on the small bodies and comets in the Oort Cloud by twisting their orbital planes to create a spiral. The spiral, Nesvorny added, is in the inner part of the Oort Cloud, the closest to us, and he still believes that the outer portion is spherical or shell-shaped. The problem of observing the Oort Cloud remains, even though the Vera C. Rubin Observatory, a powerful telescope that recently came online in Chile, could offer a hand by discovering and observing individual icy bodies in the cloud. However, according to Nesvorny, the telescope will likely discover dozens of these bodies — not the hundreds that would be required to produce a meaningful visualization of the spiral. The spiral theory helps to illuminate the dynamics of our solar system, according to Faherty. 'If you're going to come up with a theory of how solar systems evolve, you should take into account the kind of shapes you might have in their structure,' she said. 'Maybe comets helped deliver water to Earth. Maybe the building blocks of life could be out there in the Oort Cloud, so if you want to talk about the potential building blocks of life that surround our solar system, you need to understand its shape.' It's a 'dream,' she added, to be able to present science so recent in a show aimed at the general public. 'I truly believe that the planetarium, the dome itself, is a research tool,' Faherty said. 'I like to say that this is science that hasn't had time to reach your textbook yet.' The spiral finding is a wonderful example of just how much we can learn through visualizing the universe in new ways, said Malena Rice, an assistant professor of astronomy at Yale University who did not participate in the study. 'This result reshapes our mental image of our home solar system, while also providing a new sense for what extrasolar systems' Oort clouds may look like,' Rice added. 'It unites our models of the solar system with what we know about the broader galaxy, placing it into context as a dynamic system. We are not static, and we are not isolated — our solar system is shaped by its broader ecosystem, and the Oort spiral exemplifies that.' While the paper is interesting, it is almost entirely theoretical, as it is based on numerical simulations of the interactions between the sun's gravity and the gravitational pull of the rest of the Milky Way galaxy's motion, said Edward Gomez, an astrophysicist and honorary lecturer at Cardiff University in the UK. He also was not involved with the study. 'Long period comets enter the inner solar system at a range of angles, which the authors try to model using their spiral arm idea,' Gomez said in an email. 'What they are proposing could be true, but it could also be modelled by other shapes of the Oort cloud or physical processes. How to test this is their major issue, because only a handful of potential Oort cloud objects are known about.' Confirming the findings will be a challenge, noted Simon Portegies Zwart, a professor of numerical star dynamics at Leiden University in the Netherlands who was not part of the team behind the research. 'It is interesting that they found the spiral, (but) it seems unlikely that we are going to witness (it) in the foreseeable future,' he said. With luck, he added, the Vera Rubin observatory will detect a few hundred inner Oort Cloud objects, but the spiral would only be visible if many more are found: 'It therefore seems unlikely to be a clearly detectable structure.'
