The Biggest Technological Development in Human History Happened All Across the World Around the Same Time, by Groups of People With Zero Contact With One Another
Around the world, on separate continents that had no contact with each other, multiple groups of ancient humans invented farming more or less simultaneously — and scientists still don't know how or why.
Known to archaeologists and anthropologists as the Neolithic Revolution, the discovery of this historical head-scratcher is by no means new. Nevertheless, it continues to fascinate folks like Michael Marshall, an author at New Scientist who pondered this phenomenon in a new piece about this quantum leap in human development.
As a 2023 PNAS paper cited by Marshall suggests, the things scientists do know about this incredible happenstance are what make it so captivating.
After the great ice sheets age of the Pleistocene Epoch began to retreat about 11,700 years ago, humans who had gradually migrated to at least four continents — Africa, Eurasia, and North and South America — moved from hunting and gathering to domesticating plants. In as many as 24 separate sites of origin, the paper explained, people began farming within a few thousand years of each other, with no means of contact between them.
Across scientific disciplines, researchers have long been trying to figure out why this leap in evolutionary behavior occurred with so many groups simultaneously. Anthropologist Melinda Zeder, the senior scientist emeritus at the Smithsonian Institute, told PNAS in 2023 that some of her colleagues even argue that humans may have been "tricked into it by plants" — but still, there's nothing near consensus about why, exactly, our ancestors all picked up farming around the same time.
In his more recent musings, Marshall, the New Scientist writer, pointed out that agriculture may have emerged as a response to any number of external factors: food shortages, climate change, or even sociopolitical reasons as evidenced by research suggesting that a rudimentary form of property rights may have begun around the same time that farming emerged.
He then went on to hypothesize something that hasn't been studied outright before: that Neanderthals, or any other early hominin groups, may have "tried their hands at gardening, if only in a small way."
"If they were lacking some crucial cognitive or physical capability to enable gardening, I'm not sure what it was," Marshall wrote. "And if they did enjoy tending their own small gardens, that would have given our species a head start on creating full-blown farms."
Even if Neanderthals did make early attempts at agriculture, however, it wouldn't explain why subsequent evolutionary groups wouldn't have immediately followed suit, or why there was suddenly a global explosion of farming activity more than 100,00 years after the first known deforestation projects took place in modern-day Germany.
Like many worthwhile mysteries, this one doesn't have a neatly-packaged answer — and unless something unprecedented about our ancestors' agricultural practices is uncovered, it may never be explained at all.
More on our origins: Something Mysterious Swept Over Our Entire Solar System, Scientists Say
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Washington Post
13 hours ago
- Washington Post
Little-known cells might be key to human brain's massive memory
A new model of memory — and a little-heralded type of brain cell — might explain why the human brain has such a huge storage capacity, researchers reported in the journal PNAS in May. The study looks at astrocytes, star-shaped cells that interact with neurons in the brain. The brain contains billions of astrocytes, and scientists have long known they play a part in cleaning up molecules within brain synapses, the junctions where neurons come together. More recent research, though, suggests that astrocytes do more. The new model suggests the astrocytes could also be used for computation, coordinating with neurons and connecting synapses in networks. These complex connections might allow the brain to encode memories in dense networks that expand the brain's capacity beyond its neurons alone, the researchers write. 'This makes neuron-astrocyte networks an exciting candidate for biological 'hardware' implementing Dense Associative Memory,' they add. The model runs counter to the prevailing theory that memory storage occurs in synapses, and implies that the brain is capable of storing even more memories than once thought possible. The researchers also describe how the theory could be validated in the lab. 'We hope that one of the consequences of this work could be that experimentalists would consider this idea seriously and perform some experiments testing this hypothesis,' said Dmitry Krotov, a research staff member at the MIT-IBM Watson AI Lab and IBM Research and the paper's senior author, in a news release. The model could also be used as a 'fresh source of inspiration' for future artificial intelligence technology, the researchers conclude.
Yahoo
19 hours ago
- Yahoo
Hidden layer beneath Italy's Campi Flegrei caldera may explain why it's so restless
When you buy through links on our articles, Future and its syndication partners may earn a commission. A weak layer of crust deep below the floor of Italy's Campi Flegrei causes the caldera to undergo periods of earth-trembling unrest, new research has found. According to the new study, published April 5 in the journal AGU Advances, this layer sits between 1.8 and 2.5 miles (3 to 4 kilometers) deep. It is made of a rock called tuff, which has been weakened by multiple magma intrusions over tens of thousands of years. This tuff, a light rock made of compressed volcanic ash, acts like a sponge for volcanic gases rising from the magma chamber that sits at least 7.5 miles (12 km) below the surface. When these gases begin to saturate the pores in the tuff, they cause the rock to deform and even break, creating earthquakes. This finding could explain the source of Campi Flegrei's regular restless periods, said study leader Lucia Pappalardo, senior researcher at the National Institute of Geophysics and Volcanology in Italy (INGV). "Other calderas in the world are characterized by this phenomenon," Pappalardo told Live Science, "[so] we think our model can be extended to other calderas worldwide." The research is part of a larger project with the aim of better forecasting eruptions at Campi Flegrei, which is also known as the Phlegraean Fields and sits west of Naples. Roughly 500,000 people live in an area that would be swamped by boiling pyroclastic flows of hot ash and gas in the event of a caldera eruption, according to Italy's Civil Protection Department. Campi Flegrei has been erupting for at least 47,000 years and last erupted in 1538. But it undergoes periods of significant unrest, one of which has been ongoing since 2005. During these restless periods, the region shakes with frequent, mostly small, earthquakes. One of these minor quakes caused a wall to collapse at the historic site of Pompeii on Thursday (June 5), according to news reports. Pappalardo and her team wanted to understand how the structure and strength of the rocks under the caldera contribute to the volcanic activity. They used rocks drilled decades ago from deep below the caldera's center , subjecting them to a bevy of scientific analysis. They characterized the minerals and elements in the samples and also subjected them to a process called "4D computed X-ray microtomography," which allowed them to observe the structure of the rock samples while they were being compressed until they cracked. This provided information about the rocks' strength and mechanics, study co-author and INGV researcher Gianmarco Buono told Live Science. RELATED STORIES —Italy's Campi Flegrei volcano may unleash devastating eruptions more often than we thought —Were Neanderthals really killed off by Campi Flegrei, Europe's awakening 'supervolcano'? —Supervolcano 'megabeds' discovered at the bottom of the sea As the researchers conducted these tests on samples from different layers of rocks, they discovered the weak tuff layer. "This was unexpected," Pappalardo said. Using computer modeling, the researchers discovered that this layer has likely trapped numerous magma intrusions, or dykes, over the millennia. These intrusions heated and deformed the rock, weakening it. The researchers are now working to understand the ways that material from the caldera's deep magma chamber can rise to the surface, causing an eruption. But despite the caldera's frequent shuddering, there is no indication that a major eruption is imminent, Pappalardo said. "At the moment, our monitoring system is not registering any parameters that can suggest magma movement," she said. "So the eruption cannot be in a short time."
Medscape
4 days ago
- Medscape
How Today's Human Brain Became so Uniquely Human
What unique processes conspire to create a healthy, functional human brain? How can we be so genetically similar to, say, chimpanzees, and yet be light-years more sophisticated cognitively and behaviorally? It may just come down to six cells. Evolutionary biologists who study the human brain and explore questions about why we're so different from other primates are especially interested in the contrasts between humans and chimpanzees. 'We share more than 99% of our DNA with chimpanzees, yet the human and chimpanzee brains are unique. That difference has always been very fascinating to me,' said Soojin Yi, PhD, professor in the Department of Ecology, Evolution, and Marine Biology at the University of California, Santa Barbara. Yi and colleagues recently published findings in the Proceedings of the National Academy of Sciences ( PNAS ) that help deepen scientists' understanding about what's behind our brain differences. They've found that 'there is more differential gene expression in human brains,' said Yi, referring to the activation of different genes within a single brain cell type that defines that cell's purpose. What's more, she said, 'Different brain cells follow different evolutionary paths depending on their unique roles in the brain.' New Findings While previous studies have suggested that human brain evolution is linked to accelerated changes in gene expression, Yi said many questions still remain. To explore how genes in different types of human brain cells have evolved compared with those of chimpanzees, the researchers used single-cell human and nonhuman primate (chimpanzee and rhesus macaques) transcriptomic data — messenger RNA transcripts present in a specific cell type — to analyze the unique molecular profiles (the gene activity) of six brain cell types. Yi said many single-cell research approaches had focused primarily on neurons, with relatively small numbers of nonneuronal cells, so their team aimed for a more diverse approach. 'To balance the brain cellular heterogeneity and statistical rigor,' she said that in addition to looking at excitatory and inhibitory neurons, they also looked at four glial cell types — astrocytes, microglia, oligodendrocytes, and oligodendrocyte precursor cells. Each of these cell types plays an important role in brain function and health. For example, excitatory neurons transmit signals between brain regions, inhibitory neurons help control brain activity, oligodendrocytes contribute to the formation of the myelin sheath around nerve fibers, and microglia are the brain's immune cells, always on the prowl for pathogens. Star-shaped astrocytes play a variety of roles, including maintaining the blood-brain barrier and supporting neurons. What They Learned 'Compared to chimpanzee brains, the human brain showed significant signs of accelerated regulatory evolution across all of the six major cell types in the brain,' said Yi, explaining that certain genes in human brain cells have evolved to produce more of certain proteins at a faster rate than in other primates. 'It's much more extensive than previously believed,' she said. Of the 25,000 genes involved in their analysis, Yi and colleagues were able to identify differences in the expression of about 5%-10% of the genes. When they considered cell subtypes, differences in expression leapt to 12%-15%. While the researchers expected to see more regulation than what was seen in previous studies, as well as some kind of cell-type specificity, Yi said, 'We didn't expect as much cell-type specificity as we saw.' 'What was really interesting to me was that when you compared cell types, genes that are differentially expressed in microglia are very different than genes that are differentially expressed in neurons,' said Yi. The findings support the belief held among many other researchers that there is 'a tremendous amount of diversity' among even the same types of brain cells in one part of the brain compared with another, Yi said. 'You may have the same cell type [such as a neuron], but it looks a little bit different in terms of transcript profiles depending on where it is located in the brain. I think that we cannot look at the brain from just a molecular perspective. We've got to really appreciate that the brain is an amalgam of many different cell types doing their own things while also working together to do these very complex functions that our brains are capable of,' said Yi. The authors pointed out study limitations, including the fact that data from nonhuman primates came from individuals living in captive facilities, which could affect their transcriptional profiles. Another Perspective In André Sousa's lab at the University of Wisconsin-Madison, the assistant professor of neuroscience and his colleagues study human brain development and evolution. 'We try to understand the mutations that have accumulated in human DNA after our split from our closest lineage — chimpanzees, bonobos, and gorillas — that can alter gene expression,' he said. Sousa, who was not involved in the PNAS study, said the new research adds another piece to the puzzle. 'I don't think it's an 'aha moment' in the sense that several studies before this had shown this abundance of genes that are more expressed in the human brain. But most of those studies were done at the bulk tissue level. The brain is very heterogeneous, and in bulk tissue studies, you can be diluting lots of signals,' he said. Because the new study analyzed single cells, he said, 'they found way more differentially expressed genes than previous studies. And we need to be a little bit careful because it could be a bias from the methodology because when you are analyzing single cells, you increase your statistical power.' Sousa said the results of the study left him pondering the fact that 'in general, more genes are more expressed both in chimpanzees and humans than genes that are lower expressed.' And that's interesting. 'I've been thinking about it quite a lot. Why do we see more genes going up than down in all of these species? We still don't know very much about what it means. It's hard to understand what's happening because it's very complex. It can have a lot of justifications, both molecularly, what's happening in the DNA, but also evolutionarily, what are the constraints that allow a gene to be more or less expressed?' he said. Sousa said he also found it interesting that the researchers subdivided certain cell types into subgroups. 'Even within subtypes, they saw accelerated evolution in terms of more upregulated genes in humans and chimpanzees than downregulated ones, and what the interesting thing they see is that the genes that are differentially expressed in each cell tend to be different. So they speculate that that probably reflects functional specialization of these cells in these species. It's a potential explanation. But it's impossible to know for sure from this data set and will require more research,' said Sousa. The authors hope to continue studying differential gene expression at the cellular level in both human and primate brains, especially the brain cell subtypes. But Yi said as scientists continue to piece together clues to what makes today's human brain so uniquely human, all animal brain evolution is fascinating. 'There are other species with awesome brains that are doing all these special things, too,' she said.
