origin of humans (Origins)

by dhw, Friday, April 14, 2023, 11:59 (468 days ago)

An article in today’s Times contains an extraordinary contradiction.The headline is:
Grassland theory uproots story of our first steps.

Researchers in East Africa have shown that on 9 sites a group of plants known as C4 grasses were an important part of the ecosystem about 21 million years ago, which “suggests that substantial areas of open grassland existed at least ten million years earlier than was thought.” This in turn suggests that Morotopithecus – an ape that lived then and is “regarded as one of the best representatives of the ancestors to all of the living apes and humans”- would have lived in open spaces. And this is where the article contradicts itself. It begins with the following:

It was widely thought that ancient apes first adopted a vertical posture while living high in the canopies of dense forests, where the limbs of the tree would have met those of the next. Being upright, it was reasoned, would have made it easier for these animals to climb and to reach for fruit while balancing on branches. It was thought that only rarely, if ever, would they have set foot on the ground.

But after explaining all the research, the article goes on to say: “Roughly speaking, researchers have often assumed that humans came to walk on two legs because dense forests receded and grassland environments opened up. Being upright would have allowed us to see for relatively large distances across a flat savannah and would have given us an efficient running gait. However, the idea that ‘shrinking forests made us human’ seems too simplistic.”

I didn’t know researchers had "widely thought" or "often assumed" both theories at the same time! It’s the latter that I think has held sway and certainly sounds to me far more convincing than the former, since even in dense forests, ancient apes would have continued to move through the trees as they do now. And I can see nothing in the new research that makes it sound “too simplistic”. The new research need not even change our views on the timetable of events. Morotopithecus “would not have walked on two legs like a human”, so it proves nothing about the timing of bipedalism. We should bear in mind that bipedalism could have originated in a single group of anthropoids. The researchers examined nine sites. How many sites would have to be explored in order to find what may have been the single original site where a shrinking forest gave way to grassland, and a single group of anthropoids adjusted to their new surroundings by standing upright? Convergent evolution might have resulted in more than one group making the same adjustments, but this still wouldn’t invalidate the second theory.

origin of humans

by David Turell @, Friday, May 05, 2023, 20:36 (446 days ago) @ dhw

dhw: An article in today’s Times contains an extraordinary contradiction.The headline is:
Grassland theory uproots story of our first steps.

Researchers in East Africa have shown that on 9 sites a group of plants known as C4 grasses were an important part of the ecosystem about 21 million years ago, which “suggests that substantial areas of open grassland existed at least ten million years earlier than was thought.” This in turn suggests that Morotopithecus – an ape that lived then and is “regarded as one of the best representatives of the ancestors to all of the living apes and humans”- would have lived in open spaces. And this is where the article contradicts itself. It begins with the following:

It was widely thought that ancient apes first adopted a vertical posture while living high in the canopies of dense forests, where the limbs of the tree would have met those of the next. Being upright, it was reasoned, would have made it easier for these animals to climb and to reach for fruit while balancing on branches. It was thought that only rarely, if ever, would they have set foot on the ground.

But after explaining all the research, the article goes on to say: “Roughly speaking, researchers have often assumed that humans came to walk on two legs because dense forests receded and grassland environments opened up. Being upright would have allowed us to see for relatively large distances across a flat savannah and would have given us an efficient running gait. However, the idea that ‘shrinking forests made us human’ seems too simplistic.”

I didn’t know researchers had "widely thought" or "often assumed" both theories at the same time! It’s the latter that I think has held sway and certainly sounds to me far more convincing than the former, since even in dense forests, ancient apes would have continued to move through the trees as they do now. And I can see nothing in the new research that makes it sound “too simplistic”. The new research need not even change our views on the timetable of events. Morotopithecus “would not have walked on two legs like a human”, so it proves nothing about the timing of bipedalism. We should bear in mind that bipedalism could have originated in a single group of anthropoids. The researchers examined nine sites. How many sites would have to be explored in order to find what may have been the single original site where a shrinking forest gave way to grassland, and a single group of anthropoids adjusted to their new surroundings by standing upright? Convergent evolution might have resulted in more than one group making the same adjustments, but this still wouldn’t invalidate the second theory.

All Darwinist suppositions are simplistic. Apes are not generally upright. They walk on their knuckles quite constantly and become upright on occasion. Their pelvis is not built for bipedalism, like ours. Based on fossils like Lucy, bipedalism came with a slightly enhanced brain, which then went on to tremendous enhancement far beyond the needs of early ape Men. All natural suppositions are far, far to simplistic to explain the changes.

origin of humans; a new fourth branch

by David Turell @, Monday, August 07, 2023, 15:39 (352 days ago) @ David Turell

Found in China:

https://www.sciencealert.com/ancient-skull-found-in-china-is-unlike-any-human-seen-befo...

"An international team of scientists has described an ancient human fossil in China unlike any other hominin found before.

"It resembles neither the lineage that split to form Neanderthals, nor Denisovans, nor us, suggesting our current version of the human family tree needs another branch.

"The jaw, skull, and leg bones belonging to this yet-to-be classified human, labeled HLD 6, were discovered in Hualongdong, in East Asia, in 2019. In the years since, experts at the Chinese Academy of Sciences (CAS) have struggled to match the remains to a known lineage.

"The hominin's face is similarly structured to that of the modern human lineage, which split from Homo erectus as far back as 750,000 years ago. But the individual's lack of chin appears more like that of a Denisovan – an extinct species of ancient human in Asia that split from Neanderthals more than 400,000 years ago.

***

"Historically, many hominin fossils from the Pleistocene that have been found in China haven't fitted easily into any one lineage. As a result, such remains are often explained away as intermediate variations on a straight path to modern humanity; as an archaic example of a Homo sapien, for example, or an advanced form of Homo erectus.

"But this rather linear, simplistic interpretation is controversial and not widely accepted. While Homo erectus did persist in Indonesia until roughly 100,000 years ago, the remains that were recently found in East China hold a greater resemblance to other, more modern lineages of hominin.

"Previously, genome studies on Neanderthal remains in Europe and western Asia have found evidence of a fourth lineage of hominin living in the Middle to Late Pleistocene.

"But this missing group has never been officially identified in the fossil record.

***

"The fossilized jaw and skull belong to a 12- or 13-year-old, and while its face has modern-human like features, the limbs, skull cap, and jaw "seem to reflect more primitive traits," the authors of the analysis write.

"Their results complicate the path to modern humans. The mosaic of physical features found in this ancient hominin instead supports the coexistence of three lineages in Asia – the lineage of H. erectus, the lineage of Denisovan, and this other lineage that is "phylogenetically close" to us.

"Homo sapiens only appeared in China around 120,000 years ago, but it seems as though some of our 'modern' features existed here long before that. It may be that the last common ancestor of H. sapiens and Neanderthals arose in southwest Asia and later spread to all continents."

Comment: the Moroccan sapiens fossil dated at 315,000 years ago complicates the issue.

origin of humans; theory of hair loss

by David Turell @, Thursday, August 17, 2023, 22:21 (342 days ago) @ David Turell

Pure theory, but th physiological changes are enormous:

https://www.the-scientist.com/ts-digest/issue/the-roles-of-endogenous-psychedelics-18-2...

:Luscious fur coats insulate many animals from the cold and protect them from sunlight, insects, and sharp objects in their environments. Yet, somehow humans evolved to be relatively hairless. While this may appear to be a case of selection against a highly desirable trait, Nina Jablonski, who studies the evolution of human skin and skin pigmentation at Pennsylvania State University, said that our relative hairlessness arose just like other traits did: it offered evolutionary advantages.

:The origins of human hairlessness began nearly two million years ago, driven by environmental changes in locations where human ancestors lived. As wooded landscapes in equatorial Africa gave way to open grassland areas, human ancestors had to spend more time outdoors to find food and water. For walking and running long distances, early members of the genus Homo developed a modern human skeleton with long legs and shorter arms. “Around this time, humans lost most of their body hair,” said Jablonski.

"Shedding body hair was a key adaptation since, unlike most other mammals, primates lack a key mechanism for cooling the blood around the brain when it’s hot outside or after exercise. This means that the temperature of the brain increases when the body heats up, which can affect brain functions. Evolution of human hairlessness was accompanied by the Luscious fur coats insulate many animals from the cold and protect them from sunlight, insects, and sharp objects in their environments. Yet, somehow humans evolved to be relatively hairless. While this may appear to be a case of selection against a highly desirable trait, Nina Jablonski, who studies the evolution of human skin and skin pigmentation at Pennsylvania State University, said that our relative hairlessness arose just like other traits did: it offered evolutionary advantages.

"The origins of human hairlessness began nearly two million years ago, driven by environmental changes in locations where human ancestors lived. As wooded landscapes in equatorial Africa gave way to open grassland areas, human ancestors had to spend more time outdoors to find food and water. For walking and running long distances, early members of the genus Homo developed a modern human skeleton with long legs and shorter arms. “Around this time, humans lost most of their body hair,” said Jablonski.

"Shedding body hair was a key adaptation since, unlike most other mammals, primates lack a key mechanism for cooling the blood around the brain when it’s hot outside or after exercise. This means that the temperature of the brain increases when the body heats up, which can affect brain functions. Evolution of human hairlessness was accompanied by the Luscious fur coats insulate many animals from the cold and protect them from sunlight, insects, and sharp objects in their environments. Yet, somehow humans evolved to be relatively hairless. While this may appear to be a case of selection against a highly desirable trait, Nina Jablonski, who studies the evolution of human skin and skin pigmentation at Pennsylvania State University, said that our relative hairlessness arose just like other traits did: it offered evolutionary advantages.

"The origins of human hairlessness began nearly two million years ago, driven by environmental changes in locations where human ancestors lived. As wooded landscapes in equatorial Africa gave way to open grassland areas, human ancestors had to spend more time outdoors to find food and water. For walking and running long distances, early members of the genus Homo developed a modern human skeleton with long legs and shorter arms. “Around this time, humans lost most of their body hair,” said Jablonski.

"Shedding body hair was a key adaptation since, unlike most other mammals, primates lack a key mechanism for cooling the blood around the brain when it’s hot outside or after exercise. This means that the temperature of the brain increases when the body heats up, which can affect brain functions. Evolution of human hairlessness was accompanied by the development of more sweat glands and darker skin pigmentation. Sweat glands helped them dissipate heat from the skin more effectively, while darker skin pigmentation protected their mostly hairless skin from the damaging effects of solar radiation.

"According to Jablonski, the idea of whole-body cooling and heating, or thermoregulation, seems like the most likely explanation for human hairlessness based on physical evidence and our knowledge of comparative anatomy and physiology. “We were shooting in the dark decades ago. Now, we can be much, much clearer on what the likely courses of evolution were,” she said."

Comment: she is so backward in her proposal. Losing hair required all the other changes. They all had to occur together in a coordinated way by design. The hair didn't just fall out; so much more was done as the article shows.

origin of humans; a new ape ancestor

by David Turell @, Wednesday, August 23, 2023, 17:59 (336 days ago) @ David Turell

Found in Turkey:

https://www.nature.com/articles/s42003-023-05210-5

"Fossil apes from the eastern Mediterranean are central to the debate on African ape and human (hominine) origins. Current research places them either as hominines, as hominins (humans and our fossil relatives) or as stem hominids, no more closely related to hominines than to pongines (orangutans and their fossil relatives). Here we show, based on our analysis of a newly identified genus, Anadoluvius, from the 8.7 Ma site of Çorakyerler in central Anatolia, that Mediterranean fossil apes are diverse, and are part of the first known radiation of early members of the hominines. The members of this radiation are currently only identified in Europe and Anatolia; generally accepted hominins are only found in Africa from the late Miocene until the Pleistocene. Hominines may have originated in Eurasia during the late Miocene, or they may have dispersed into Eurasia from an unknown African ancestor. The diversity of hominines in Eurasia suggests an in situ origin but does not exclude a dispersal hypothesis.

"The origin of the hominines is among the most hotly debated topics in paleoanthropology. The traditional view, ever since Darwin, holds that hominines and hominins originate in Africa, where the earliest hominins are found and where all extant non-human hominines live. More recently a European origin has been proposed, based on the phylogenetic analysis of late Miocene apes from Europe and Central Anatolia1. The fossils described here attest to a lengthy history of hominines in Europe, with multiple taxa in the eastern Mediterranean known for at least. Our phylogenetic analysis, based on the new specimens described here and a large sample of other fossil and extant hominoids, Our most parsimonious phylogenetic results suggest that hominines in the eastern Mediterranean evolved from dryopithecins in central and western Europe, though there are alternative interpretations. Either way, the oldest known hominines are European. They may have dispersed into Europe from ancestors in Africa, only to become extinct. However, the more likely and more parsimonious interpretation is that hominines evolved over a lengthy period in Europe and dispersed into Africa before 7 Ma.

***

"...the sample of ape fossils from Çorakyerler demonstrates that great ape diversity in the eastern Mediterranean is greater than previously believed and that hominines had diversified into multiple taxa long before their first documented appearance in Africa."

Comment: what is of interest is that apes, prior to hominin appearance were all over Europe and may not have been in Africa, not as I previously thought.

origin of humans; early use of wood

by David Turell @, Wednesday, September 20, 2023, 18:11 (308 days ago) @ David Turell

Half a million years ago:

https://www.sciencealert.com/evidence-of-a-wooden-structure-that-predates-our-species-u...

"Uncovered in 2019 at the Kalambo Falls in Zambia, the objects provide archaeologists with an exceptionally rare look at wooden technology from mid-Paleolithic Africa, a time better known for an acceleration in the innovations of stone tools. The logs also predate the evolution of our own species, Homo sapiens.

"An analysis conducted by an international team of researchers has now come to the astonishing conclusion that the wooden artifacts were once part of a permanent structure of some kind, such as a platform or building.

"If so, the discovery complicates the conventional image of hominins as nomads hunting migrating herds or gathering seasonal flora with relatively basic tools.

"'This find has changed how I think about our early ancestors," says University of Liverpool archaeologist Larry Barham, leader of a project researching Stone Age technology called Deep Roots of Humanity.

"'Forget the label 'Stone Age,' look at what these people were doing: they made something new, and large, from wood. They used their intelligence, imagination, and skills to create something they'd never seen before, something that had never previously existed." (my bold)

"While indirect signs of woodworking by mid-Pleistocene hominins can be found in the form of plant residue or patterns of wear on stone tools, Stone Age items carved from timber rarely survive the ages.

"At nearly 800 thousand years old, a solitary plank with a polished surface found in Israel is the current record holder for world's earliest prime example of carpentry.

***

"While it's impossible to determine the purpose of the interlocking sections, viewed in association with other discoveries at the site, including several other small wooden artifacts and stone implements, the authors tentatively interpret the findings as structural.

"To determine when the items may have been crafted, the researchers applied a version of infrared stimulated luminescence dating to determine when minerals called feldspar in the surrounding sediment were last bathed in sunlight.

"That figure, of just under 450 to 500 thousand years ago, puts the construction well before the era in which our own species is believed to have emerged.

"To take the time and effort to construct large, wooden items that can't be easily transported, we might presume the structure's makers would be relatively settled in one place, or at least frequent visitors.

"'They transformed their surroundings to make life easier, even if it was only by making a platform to sit on by the river to do their daily chores. These folks were more like us than we thought," says Barham.

"With its perennial waters, lush greenery, and stunning views, it's not hard to see why our ancestors kept coming back to the falls at Kalambo River since long before we were even human."

Comment: could these folks be Erectus? And quite advanced for primarily stone age. Note my bold. They had a very competant brain.

origin of humans; evolution of the skull

by David Turell @, Thursday, October 12, 2023, 18:08 (286 days ago) @ David Turell

Started with a fish 450 million year ago:

https://www.discovermagazine.com/the-sciences/ancient-fish-head-fills-a-100-million-yea...

"This 455-million-year-old specimen of Eriptychius americanus contains the earliest ever seen neurocranium — the cartilage protecting the fish’s brain — and one of the strangest. According to the study, the fish’s cartilage fits neatly yet loosely around the brain in a design with no known analogue.

"As the earliest vertebrate neurocranium ever studied, it fills a 100-year gap between the earliest such fossils ever recovered previously (from about 400 million years ago) and the origin of vertebrate fish some 500 million years ago.

"One of the greatest innovations of the vertebrate body plan, the neurocranium both protects the brain and helps to connect it to sensory organs, the mouth and more. In humans, the neurocranium is the portion of the skull that contains the brain, and the skull's seam-like sutures allow it to expand all the way until early adulthood to allow for growth.

"While the human skull is composed of 22 different bony pieces, E. americanus’ neurocranium was composed of 10 long pieces of cartilage that fit together without being fused, according to the X-ray scans. The imaging also revealed that canals snaked through the cartilage to deliver either blood supply or connections to sensory organs. The fish’s skin wrapped tightly around the whole structure, though the scientists noted a clear anatomical distinction between the two.

"This novel neurocranium falls somewhere between the loose, open cartilage style seen with lampreys and the more closed-off designs present in gnathosomes, a group that includes humans.

"Vertebrates exist with both structures, and scientists have tried to determine how they evolved. The new paper speculates that the largely locked-up cranium we enjoy evolved later down the line from E. americanus.

"Ultimately, that layout became a central part of gnathosomes as we know them (and us) today.

“'These are tremendously exciting results that may reveal the early evolutionary history of how primitive vertebrates protected their brains,” said Ivan Sansom, a paleobiologist."

Comment: the brain is so important it must have a protective casing. How did an unguided evolution have the foresight to recognize the potential dangers to a soft brain? This shows the purposeful design a designer would follow. When studying evolution, it is always important to ask why and how this new event happened. Look for purpose and you will see design.

origin of humans; Erectus in Ethiopian highlands

by David Turell @, Friday, October 13, 2023, 20:29 (285 days ago) @ David Turell

Two million years ago:

https://www.newscientist.com/article/2397291-early-humans-lived-in-ethiopian-highlands-...


"Ancient humans were living in the highlands of what is now Ethiopia as early as 2 million years ago. A reanalysis of a fossilised jawbone from the region confirms that it belonged to a Homo erectus, and represents the earliest evidence of hominins living in such high-altitude areas.

"The highlands represent “a third pole for human evolution in Africa”, says Margherita Mussi of the Italo-Spanish Archaeological Mission at Melka Kunture and Balchit, based in Rome. Hominins have been found in large numbers in eastern and southern Africa, but not to date in upland areas.

***

"Mussi and her team used synchrotron imaging to study Little Garba’s teeth, which hadn’t yet erupted from the jawbone. They compared the shape of the teeth to those of multiple hominin species. “The teeth are a very good marker, so we can say for sure this is indeed an early Homo erectus,” says Mussi.

"In a previous study published in 2021, Mussi’s team also re-dated the Garba IV site. It consists of layers of sediment laid down over time. In the sediments, the researchers found traces of past shifts in Earth’s magnetic field, which could be matched to similar records elsewhere. Based on this, they conclude that Little Garba is 2 million years old. This makes it one of the oldest H. erectus ever found.

***

"Furthermore, the researchers re-examined the stone tools found in the sediments at Garba IV. They say there is a transition from older and simpler Oldowan tools to more sophisticated Acheulean tools between 2 and 1.95 million years ago. The Acheulean tools were harder to make because they required careful planning, but they opened up a wider range of foods.

"Putting these lines of evidence together, Mussi argues that the H. erectus population had to adapt to conditions in the highlands, and developed new styles of stone tools to do so."

Comment: H. erectus is our direct ancestor. They spread all over the Eastern hemisphere and undoubtedly coexisted with early H. sapiens

origin of humans; early sapiens Neanderthal mix

by David Turell @, Tuesday, October 24, 2023, 17:30 (274 days ago) @ David Turell

Not just in Europe:

https://www.sciencealert.com/unknown-human-lineage-found-buried-in-the-neanderthal-geno...

"As Homo sapiens migrated into Eurasia more than 70,000 years ago, much of the continent was already inhabited by Neanderthals, hominins who shared an ancestor with us but had spent roughly half a million years diverging.

***

"During their Late Pleistocene overlap in Eurasia, however, we know the two hominin species sometimes interbred, since many humans today still have traces of Neanderthal DNA.

"And according to a new study, this relationship goes back even farther than we thought, with a long-forgotten earlier chapter re-emerging from clues in the Neanderthal genome.

"When modern humans reached Eurasia in the Late Pleistocene, the study suggests, Neanderthals living there already carried traces of our species' DNA, apparently from a much older, previously unknown run-in with an even more ancient lineage of anatomically modern humans.

"That would mean some Homo sapiens ventured into Eurasia more than 250,000 years ago, the study's authors report, long before the continent's earliest evidence of modern humans. For context, the fossil record indicates our species evolved in Africa only 300,000 years ago.

"'We found this reflection of ancient interbreeding where genes flowed from ancient modern humans into Neanderthals," says Alexander Platt, an evolutionary biologist at the University of Pennsylvania.

"'This group of individuals left Africa between 250,000 and 270,000 years ago. They were sort of the cousins to all humans alive today, and they were much more like us than Neanderthals," Platt says.

"The early modern humans who made it to Eurasia later died out, the researchers note, and Neanderthals continued to dominate the continent for another 200,000 years or so. Hidden in the Neanderthal genome, however, were remnants from this ancient encounter.

"To reveal this, the study's authors first followed clues uncovered by another recent study, which found Neanderthal-like chunks of DNA – called Neanderthal-homologous regions (NHRs) – in multiple present-day human populations from Africa.

"This was surprising, since most interbreeding between modern humans and Neanderthals likely happened in Eurasia. It raised questions about how Neanderthal DNA, typically associated with Eurasian ancestry, could be seemingly abundant in Africa.

***

"NHRs were found in every population tested, showing they are widespread in Africa. Most of this 'Neanderthal-like' DNA originated not with Neanderthals, however, but with ancient modern humans who migrated from Africa to Eurasia about 250,000 years ago.

"As the newcomers interbred with Neanderthals, they left a legacy: Up to 6 percent of the Neanderthal genome came from early members of our species, the researchers report.

"The study also found evidence that, in certain populations, Neanderthal genes were introduced by people migrating back to Africa from Eurasia, where their ancestors had presumably interbred with Neanderthals."

Comment: Lot's more intermixing/interbreeding than realized. Sapiens were obviously prone to migration looking for the best area to live.

origin of humans; migration to Asia controlled by climate

by David Turell @, Tuesday, January 09, 2024, 16:07 (197 days ago) @ David Turell

About 100,000 years ago as climate changed:

https://mail.google.com/mail/u/0/#inbox/FMfcgzGwJchvfjLhvTTCjpkhmdChWdGc

"Our species evolved in Africa some 300,000 years ago, but fossil evidence suggests people didn't begin migrating into East Asia until around 100,000 years ago. What took them so long? A new analysis of ancient climate conditions suggests these eastbound migrants had to wait until a strengthening monsoon pattern across southern Asia rolled out a green carpet for them.

"Before about 125,000 years ago, people journeying east out of the African continent would have encountered cold, arid conditions inhospitable to modern humans. But then, a lot changed—including greenhouse gas concentrations, the volume of ice covering the Northern Hemisphere, and the intensity of sunlight reaching Earth, ultimately governed by the planet’s tilt, wobble, and solar orbit. Combined, these increased heat and rainfall across the region, and this new climate produced a green corridor, the authors argue, that would have proven irresistible to hunter-gatherers at the time, drawing them into East Asia.

“'Now we can confidently add rain and water to the equation that makes environment more suitable for H. sapiens settlement,” says anthropologist and study author María Martinón-Torres."

From the original article:

https://www.science.org/content/article/strong-monsoons-may-have-carved-path-early-huma...

"Evidence from fossils, artifacts, and DNA has established that H. sapiens evolved in Africa by roughly 300,000 years ago. About 60,000 years ago, the lineage that led to people alive today began to disperse across all of Earth’s habitable lands. But remains that resemble H. sapiens, reportedly dated to between 120,000 and 70,000 years old, have surfaced at various East Asian sites, including Fuyan Cave in China and Tam Pà Ling in Laos. Those putative modern human groups may not have persisted, and anthropologists debate what drove them to venture out in the first place.

***

"A team led by Chinese Academy of Sciences geologist Hong Ao sought a record that could track the timing of these changes on a scale of centuries. In 2021, they found what they were looking for: a slope of the Chinese Loess Plateau where windblown sediment had accumulated relatively quickly, creating a high-resolution record. For 1 month, the researchers dug steps into the plateau and shoveled sediments about every 2 centimeters along a 44-meter slope. From 2066 samples, they measured magnetic particles that form more abundantly as wetter conditions hasten the formation of soils with iron minerals. This provided snapshots of monsoon intensity every 100 to 800 years for the past 280,000 years.

"The researchers combined this record with a climate simulation model and existing environmental reconstructions to make estimates for annual rainfall, summer temperature, and other climate variables.

***

"How wet Asia gets, the researchers learned, varies with multiple factors, including greenhouse gas concentrations, the amount of ice covering the Northern Hemisphere, and the intensity of sunlight reaching Earth, ultimately governed by the planet’s tilt, wobble, and solar orbit. Between 125,000 and 70,000 years ago, when H. sapiens likely apparently first ventured there, East Asia had spells of 27.5°C summers with more rain than the present day—an enticing environment for mammals and the hunter-gatherers tracking them.

“'Now we can confidently add rain and water to the equation that makes environment more suitable for H. sapiens settlement,” says study author María Martinón-Torres, an anthropologist with Spain’s National Research Center on Human Evolution."

Comment: H. erectus was certainly prone to migration, always looking for the best spots to live. This theory does not explain the thinking that North America was colonized across an ice bridge to Alaska. Not a hospitable climate in that instance.

origin of humans; migration to the Americas

by David Turell @, Wednesday, January 10, 2024, 21:32 (196 days ago) @ David Turell

Much earlier than previously known:

https://www.smithsonianmag.com/smithsonian-institution/thirteen-discoveries-made-about-...

"...tool use doesn’t have to be confined to purely practical purposes. Modern human cultural expression is characterized by the production and aesthetic significance of jewelry, clothing and other items. Two stories from this year use jewelry and personal adornments specifically to better unravel the story of human migration and existence.

"First, a study published in July by Thais Pansani and colleagues investigates the remains of giant sloths from Santa Elina in central Brazil. At this site, abundant stone tools are intermixed with the fossils of the extinct ground sloth Glossotherium phoenesis, which grew to be 10 to 13 feet long and weighed 1.1 to 1.6 tons. These fossils include thousands of osteoderms, bony plates in the sloth’s skin similar to the armor on an armadillo, to whom sloths are closely related.

"Strikingly, three of these osteoderms had holes drilled into them by humans, which, according to the authors, means they were fashioned into pendants to be worn. These drill holes were also made prior to the bones becoming fossilized, meaning that humans must have existed alongside these megafauna to have access to their fresh bones.

"The dating of the oldest human activity at this site, including these giant sloth bone pendants, to around 27,000 years ago means that modern humans reached central Brazil prior to the last glacial maximum around 20,000 years ago. This study contributes to the growing body of evidence demonstrating that modern human migration into the Americas is much older than previously accepted."

Comment: migration was certainly Eastward. The date of 20,000 year ago for the last glaciation means a so-called ice-bridge existed, but recognizing how humans sailed around the Pacific, my bet is they sailed to South America at these much earlier times.

origin of humans; migration to Europe

by David Turell @, Thursday, February 01, 2024, 15:32 (174 days ago) @ David Turell

Specific tools found from before 35,000 years ago:

https://www.science.org/content/article/puzzling-prehistoric-artifacts-served-practical...

"In 2015, archaeologists working at a cave in southwestern Germany found an enigmatic perforated baton in a cave called Hohle Fels. It was a near-perfect match for an artifact found in 1983 in a cave down the road. Carved from single pieces of mammoth ivory, the Hohle Fels baton—roughly 20 centimeters long, about the length of a large paperback book—had multiple holes with spiraling grooves around the openings.

"Similar objects have been found elsewhere in Germany and in nearby France, often made from ivory or antler. They date from the last ice age, more than 35,000 years ago, a time when human hunters and foragers were flourishing across Europe and creating cave paintings, figurines, and other expressions of creativity. In the past, many archaeologists interpreted these batons as a noisemaker or ritual object, a sort of ice age magic wand or scepter. “Ritualism was something they used to ascribe everything to,” says Wei Chu, an archaeologist at Leiden University.

"In a new paper out today in Science Advances, researchers suggest the tools were used for a more prosaic purpose: to make rope.

***

"After removing tiny bits of soil near the holes, Veerle Rots, an archaeologist at the University of Liège and co-author of the new research, peered at their edges under a microscope and found tiny plant in much higher concentrations than in the surrounding soil. “The combination of looking at it, seeing the grooves were intentionally made, and finding those fibers made us think it was a tool” used for turning plant fiber into rope, Rots says.

"Although perishable items such as fabric and cord haven’t survived the millennia, hunter-gatherers couldn’t have survived without them. Twine, cord, and rope were needed for a host of tasks, including fastening stone points to spears, tying down tents, and securing packages of meat. “Cords are very important in people’s lives, but we hardly ever have traces of them,” Rots says. “This tool permitted us to reflect on the whole process.”

"Once the researchers had a hypothesis, they set out to test it. An expert carver recreated copies of the baton, first out of wood and then—because mammoth ivory was difficult to come by—the tusk of an African warthog.

"The team next turned to historic depictions of ropemaking. In the Middle Ages, ropemakers used blocks of wood with similar-size drilled holes. By pulling fibers through adjacent holes, artisans working in teams of three or four were able to maintain tension on the fibers while braiding them into multistrand ropes. With a little practice, the archaeologists found their replica tool “works very efficiently and quickly to make thick cords with very little effort,” Rots says.

"The researchers managed to fashion 5 meters of rope in about 10 minutes with their replica batons. For fiber, they used everything from flax and hemp to cattail reeds—all plants that would have grown near the Hohle Fels and Geissenklösterle caves 30,000 years ago. The ropes proved capable of supporting the weight of one of the team’s larger members. Reeds made the strongest rope fiber.

***

"The find is more evidence the “cave man” designation applied to people in the past underestimates their innovative capacities. “People back then weren’t stupid,” Conard says. “They knew how to do all kinds of things.'”

Comment: the illustrations show the actual process. The final paragraph says it all. H. sapiens were bright folks.

origin of humans; migration to Europe

by David Turell @, Thursday, February 01, 2024, 15:50 (174 days ago) @ David Turell

Around 45,000 year ago:

https://www.science.org/content/article/mysterious-ice-age-artifacts-suggest-modern-hum...

"More than 45,000 years ago, small bands of hunters chased horses, reindeer, and mammoth over a vast expanse of tundra that stretched across most of northern Europe. They rarely stayed anywhere for long, leaving behind a scattering of stone tools and traces of the odd campfire in the depths of caves.

"For more than a century, archaeologists debated whether these artifacts were left by some of the last Neanderthals to roam Europe—or the first modern humans to brave the northern reaches of the continent.

"A trio of papers published today in Nature and Nature Ecology & Evolution may help settle the question. Between 2016 and 2022, archaeologists recovered fragments of hominin bone from a cave in the central German village of Ranis. The bones were at least 45,000 years old, and their DNA has now identified them as the remains of our species. “We now have a Homo sapiens population in northern Europe long before Neanderthals disappeared,” says Marcel Weiss, an archaeologist at the Friedrich Alexander University of Erlangen-Nuremberg who supervised the excavations.

"What’s more, the bones were found with a type of stone blade known from other sites across northern Europe, from the British Isles to modern-day Poland. Archaeologists once assumed they were the handiwork of Neanderthals, but the Ranis bones hint that the tools—a style called Lincombian-Ranisian-Jerzmanowician (LRJ)—are modern humans’ calling card. “This suggests that early humans were far more widely spread, much earlier than we thought,” says University of Vienna archaeological scientist Tom Higham, who was not involved with the research. “What seems to be emerging is a complex mosaic pattern” in northern Europe, with pioneering bands of modern humans sharing the continent with Neanderthals.

"The Ranis bones aren’t the only evidence for H. sapiens’s early presence in Europe: In 2022, members of the same team reported finding 45,000-year-old modern human remains at a cave in Bulgaria called Bacho Kiro. A woman’s skull reported last year from Zlatý kůň, a site in the Czech Republic, had well-preserved modern human DNA and may be more than 43,000 years old. Another team has claimed still older H. sapiens finds—including a tooth from a cave in southern France that may be 54,000 years old.

***

"The new evidence from Ranis, added to Bacho Kiro and Zlatý kůň suggests that rather than a single wave, small groups of modern humans moved from Africa into Europe piecemeal starting about 48,000 years ago, overlapping with Neanderthals for many millennia. “That implies coexistence and competition and interaction. It’s a much more complex and diverse process,” says Carles Lalueza-Fox, an archaeologist who now directs the Museum of Natural Sciences of Barcelona and was not part of the research team.

"Genetic evidence has confirmed that the two groups sometimes met and interacted. DNA results from Bacho Kiro, for example, showed that people there had Neanderthal ancestors within six generations, although the Zlatý kůň woman had no recent Neanderthal ancestry. Analysis of the genetic results from the Ranis individuals is ongoing, but early results hint at the mobility of these small bands, showing close connections to the skull found at Zlatý kůň, more than 500 kilometers to the south.

***

"Oxygen isotopes from horse teeth in the cave’s LRJ layers, for example, captured a hyperlocal weather report from 48,000 years ago. The average forecast? What researchers call “peri-Arctic,” or 7°C to 15°C colder than modern-day Germany. “These guys spread in a very hostile environment, like the north of Scandinavia today,” says Jean-Jacques Hublin, a paleoanthropologist at the College of France who led the Ranis research.

***

"Though they apparently managed to make a go of it for millennia, ultimately the Ranis people and their contemporaries “weren’t entirely successful,” Hublin says. “They didn’t replace the Neanderthals living farther south, and at least when we try to trace the descendants of people of this time, from Bacho Kiro, it seems we have very little of their genome in later populations.” About 40,000 years ago, a new wave of modern humans arrived and proliferated on a much larger scale. It was those people who soon pushed Neanderthals to the margins, and then to extinction."

Comment: we are seeing a gradual exposition of how sapiens arrived and took over Europe at very cold times. The issue becomes what made them leave warmer climates? Were they forced to?

origin of humans; early migration to Jordan

by David Turell @, Friday, February 09, 2024, 19:05 (166 days ago) @ David Turell

700,000 years earlier than previously thought:

https://www.newscientist.com/article/2416647-hominins-may-have-left-africa-700000-years...

"Our ancient ancestors may have ventured outside of Africa much earlier than previously believed, according to archaeologists working in Jordan. They say they have found stone tools there that were made and used 2.5 million years ago.

“'Now we know that hominins left Africa at least 700,000 years before we thought,” says Walter Neves at the University of São Paulo in Brazil.

***

"To firm up their case, they have re-examined the purported stone tools and described them in detail. The tools, they say, are a type called Oldowan that have been found at multiple locations in Africa, dating back as far as 3 million years ago.

***

"...he is persuaded that Neves and his colleagues really have made an important discovery. “My take on this is that there is very likely a hominin in Jordan making artefacts prior to 2 million years ago,” says Braun. “I am uncertain exactly how much earlier than 2 million years ago.”

"Because some of the tools were found just above the basalt layer, Neves argues they are probably 2.5 million years old. This makes them older than any known fossils of H. erectus, implying that another hominin species was the first to leave Africa.

"Neves points to Homo habilis, which may have been present 2.3 million years ago or even earlier. “Our hypothesis is that the first hominin to have left Africa was Homo habilis and not Homo erectus,” he says.

"Other researchers have claimed to have evidence of hominins outside Africa older than the Dmanisi remains. At Shangchen in China, researchers have described 2.1-million-year-old stone tools, while at Longgupo, also in China, there are stone artefacts and hominin remains that have been claimed to be 2.5 million years old. There are also claims of stone tools in northern India 2.6 million years ago. However, none of these claims have been widely accepted. Either the artefacts themselves, or their ages, or both, have been questioned.

“'The truth is that we know very little about the earliest excursions of hominins [outside Africa],” says Braun."

Comment: Erectus loved to migrate, gradually moving east and finally north. I think habilis is just an early erectus.

origin of humans; migration to Europe

by David Turell @, Monday, March 18, 2024, 14:48 (128 days ago) @ David Turell

Related to climate 900 thousand years ago:

https://www.sciencealert.com/study-reveals-how-ancient-humans-escaped-climate-extinctio...

"Some 900,000 years ago, humans nearly went extinct.

"According to the results of a genomics study published last year, modern humanity's ancestors were reduced to a breeding population of barely 1,300 individuals in a devastating bottleneck that brought us to the very brink of annihilation. Now, a new study has found that a mass migration of humans out of Africa occurred at the same time.

"It's a discovery that confirms the previous dating of the population decline, and suggests that the two are linked to a common denominator; an event known as the Mid-Pleistocene Transition, in which Earth's climate underwent a period of utter turmoil, wiping out many species.

"The movement of early humans into and across Europe and Asia from Africa is difficult to reconstruct. The best evidence we have consists of a sparse record of bones and mostly stone artifacts, which can be challenging to date. However, the evidence suggests that it wasn't one event, but multiple waves of early hominids and human ancestors that packed up their lives and made long journeys into new environments.

"Two recent studies have linked human migration to a population bottleneck, based on different types of analysis. A close reading of the human genome found that a population bottleneck caused a loss of genetic diversity some 900,000 years ago. A second study, published a few weeks later, studied early archaeological sites in Eurasia, and dated the bottleneck to 1.1 million years ago.

***

"First, the researchers re-evaluated records of sites of early hominid habitation across Eurasia, and found a cluster of sites reliably dated to 900,000 years ago. In comparison, the dating on older sites used as evidence of a population bottleneck was more ambiguous and therefore disputable.

"They compared their findings to marine sediment records, which preserve evidence of changes in the climate in the form of oxygen isotopes. Ratios of oxygen trapped in sediment layers indicate whether the climate was warmer or cooler at the time the minerals were deposited.

"The genomic data and the dating of the hominid sites together suggest that the bottleneck and the migration were simultaneous. During the Mid-Pleistocene Transition, global ocean levels dropped, and Africa and Asia dried out, with large patches of aridity. Hominids living in Africa would have faced horrible conditions depriving them of food and water. Fortunately, with the falling sea level, land routes into Eurasia became available and they were able to skedaddle, according to the researchers' model.

"This is not to say, they carefully note, that hominids had not migrated previously. Rather that the population bottleneck in the ancestor of modern Homo sapiens and the migration thereof occurred at the same time as a result of the climate upheaval that was occurring some 900,000 years ago.

"'We suggest that the enhanced aridity during marine isotope stage 22 that caused the spread of savanna and arid zones across much of continental Africa pushed early Homo populations in Africa to adapt or migrate to avoid extinction," they write in their paper.

"'Rapid migration in response to a severe climate trigger and concomitant means to escape is what can account for the … migration out-of-Africa at 0.9 million years ago and contribute to the modern genomic evidence in modern African populations of the bottleneck.'"

Comment: no question that marked climate changes will drive migrations. The 'population bottleneck' has been presented here previously.

origin of humans; migration to Persian plateau

by David Turell @, Monday, March 25, 2024, 19:07 (121 days ago) @ David Turell

Trying to follow the paths:

https://www.sciencedaily.com/releases/2024/03/240325114147.htm

"A new study combining genetic, palaeoecological, and archaeological evidence has unveiled the Persian Plateau as a pivotal geographic location serving as a hub for Homo sapiens during the early stages of their migration out of Africa.

"This revelation sheds new light on the complex journey of human populations, challenging previous understandings of our species' expansion into Eurasia.

"The study, published in Nature Communications, highlights a crucial period between approximately 70,000 to 45,000 years ago when human populations did not uniformly spread across Eurasia, leaving a gap in our understanding of their whereabouts during this time frame.

"Key findings from the research include:

"The Persian plateau as a hub for early human settlement: Using a novel genetic approach combined with palaeoecological modelling, the study revealed the Persian Plateau as the region where from population waves that settled all of Eurasia originated.

"This region emerged as a suitable habitat capable of supporting a larger population compared with other areas in West Asia.

"Genetic resemblance in ancient and modern populations: The genetic component identified in populations from the Persian Plateau underlines its long-lasting differentiation in the area, compatible with the hub nature of the region, and is ancestral to the genetic components already known to have inhabited the Plateau.

"Such a genetic signature was detected thanks to a new approach that disentangles 40,000 years of admixture and other confounding events. This genetic connection underscores the Plateau's significance.

***

"'The Persian Plateau emerges as a key region, underlining the need for further archaeological explorations."

"First author Leonardo Vallini of the University of Padova, Italy, said: "The discovery elucidates a 20,000 year long portion of the history of Homo sapiens outside of Africa, a timeframe during which we interacted with Neanderthal populations, and sheds light on the relationships between various Eurasian populations, providing crucial clues for understanding the demographic history of our species across Europe, East Asia, and Oceania."

"'The Persian Plateau emerges as a key region, underlining the need for further archaeological explorations.'"

Comment: the area of Israel has shown many ancient sites for sapiens activity on their way to the Persian plateau.

origin of humans; the loss of Neanderthals

by David Turell @, Wednesday, March 27, 2024, 12:39 (120 days ago) @ David Turell

They lost, we won, but why?:

https://www.sciencealert.com/modern-humans-thrived-while-neanderthals-disappeared-but-n...

"Why did humans take over the world while our closest relatives, the Neanderthals, became extinct? It's possible we were just smarter, but there's surprisingly little evidence that's true.

"Neanderthals had big brains, language and sophisticated tools. They made art and jewellery. They were smart, suggesting a curious possibility. Maybe the crucial differences weren't at the individual level, but in our societies.

"Two hundred and fifty thousand years ago, Europe and western Asia were Neanderthal lands. Homo sapiens inhabited southern Africa. Estimates vary but perhaps 100,000 years ago, modern humans migrated out of Africa.

"Forty thousand years ago Neanderthals disappeared from Asia and Europe, replaced by humans. Their slow, inevitable replacement suggests humans had some advantage, but not what it was.

***

"Neanderthals mastered fire before we did. They were deadly hunters, taking big game like mammoths and woolly rhinos, and small animals like rabbits and birds.

"They gathered plants, seeds and shellfish. Hunting and foraging all those species demanded deep understanding of nature.

"Neanderthals also had a sense of beauty, making beads and cave paintings. They were spiritual people, burying their dead with flowers.

"Stone circles found inside caves may be Neanderthal shrines. Like modern hunter-gatherers, Neanderthal lives were probably steeped in superstition and magic; their skies full of gods, the caves inhabited by ancestor-spirits.

"Then there's the fact Homo sapiens and Neanderthals had children together. We weren't that different. But we met Neanderthals many times, over many millennia, always with the same result. They disappeared. We remained.

***

"Modern hunter-gatherers provide our best guess at how early humans and Neanderthals lived. People like the Namibia's Khoisan and Tanzania's Hadzabe gather families into wandering bands of ten to 60 people. The bands combine into a loosely organised tribe of a thousand people or more.

"These tribes lack hierachical structures, but they're linked by shared language and religion, marriages, kinships and friendships. Neanderthal societies may have been similar but with one crucial difference: smaller social groups.

"What points to this is evidence that Neanderthals had lower genetic diversity.

"In small populations, genes are easily lost. If one person in ten carries a gene for curly hair, then in a ten-person band, one death could remove the gene from the population. In a band of fifty, five people would carry the gene – multiple backup copies. So over time, small groups tend to lose genetic variation, ending up with fewer genes.

"In 2022, DNA was recovered from bones and teeth of 11 Neanderthals found in a cave in the Altai Mountains of Siberia. Several individuals were related, including a father and a daughter – they were from a single band. And they showed low genetic diversity. (my bold)

***

"But the Altai Neanderthals often had one version of each gene. As the study reports, that low diversity suggests they lived in small bands – probably averaging just 20 people.

"It's possible Neanderthal anatomy favoured small groups. Being robust and muscular, Neanderthals were heavier than us. So each Neanderthal needed more food, meaning the land could support fewer Neanderthals than Homo sapiens.

"And Neanderthals may have mainly eaten meat. Meat-eaters would get fewer calories from the land than people who ate meat and plants, again leading to smaller populations.

"If humans lived in bigger groups than Neanderthals it could have given us advantages.

***

"Big societies have other, subtler advantages. Larger bands have more brains. More brains to solve problems, remember lore about animals and plants, and techniques for crafting tools and sewing clothing. Just as big groups have higher genetic diversity, they'll have higher diversity of ideas.

"And more people means more connections. Network connections increase exponentially with network size, following Metcalfe's Law. A 20-person band has 190 possible connections between members, while 60 people have 1770 possible connections.

"Information flows through these connections: news about people and movements of animals; toolmaking techniques; and words, songs and myths. Plus the group's behaviour becomes increasingly complex.

***

"To paraphrase poet John Dunne, no man – and no Neanderthal – is an island. We're all part of something larger. And throughout history, humans formed larger and larger social groups: bands, tribes, cities, nation states, international alliances.

"It may be then that an ability to build large social structures gave Homo sapiens the edge, against nature, and other hominin species."

Comment: this approach of larger civil and societal groups as a human advantage makes more sense than any other discussion I've seen.

origin of humans; h Erectus in Siberia

by David Turell @, Sunday, April 21, 2024, 18:18 (94 days ago) @ David Turell

417,000 years ago:

https://www.newscientist.com/article/2427163-early-humans-spread-as-far-north-as-siberi...

"A site in Siberia where early humans lived has been dated to 417,000 years ago, making it by far the most ancient early human site found this far north.

“'This site dramatically revises our understanding of when humans reached high latitudes,” John Jansen at the Czech Academy of Sciences told a press conference on 16 April. Other early human sites in the Arctic region are no more than 45,000 years old, he says.

***

"The site at Diring Yuriakh, near the city of Yakutsk in Russia, was discovered in 1982. It consists of primitive stone tools buried in layers of wind-blown sand. In 1997, it was shown that these layers were at least 260,000 years old, but their actual age remained unknown.

"Now, Jansen and his colleagues have used a method called cosmogenic dating to date the layers to 417,000 years ago, plus or minus around 80,000 years.

"The timing coincides with a warm interglacial period, he says, so it makes sense that people moved north at this time. “The age perfectly corresponds with the interglacial,” says Jansen. Later glacial periods would have forced them to move back south, he thinks.

"No human remains have been found at the Siberian site, but based on the timing it is likely the inhabitants were Homo erectus, a species that evolved around 2 million years ago and spread from Africa to Eurasia.

"Beyond this, nothing is known about them. We don’t know if they used fire or made clothes, says Jansen, let alone if they had any specific adaptions to living so far north.

"The earliest evidence of humans in North America is from around 33,000 years ago.

"If any early humans did make it to North America at this time, it seems that they went extinct before modern humans arrived, as there is no genetic trace of them within modern American peoples.

"It is possible that some human DNA from this time remains frozen in Siberian permafrost, but the site can no longer be visited because of Russia’s invasion of Ukraine, says Jansen. The samples that were dated were taken in 2021, before the invasion.

“'These are really interesting results,” says Chris Stringer at the Natural History Museum in London

***

“'Given the warmth of this interglacial, it is certainly plausible that early humans were able to move even further north in places like Siberia, at least briefly,” he says. “However, I think it is a speculation too far to suggest they could even have reached the Bering Strait and the Americas at this time.”

***

"Earlier this year, Jansen and colleagues dated another early site in Ukraine to 1.4 million years ago."

Comment: our early ancestors surely were opportunistic wanderers. Everything must have looked better over the next hill.

origin of humans; a new massive analysis

by David Turell @, Saturday, March 30, 2024, 17:46 (116 days ago) @ David Turell

A study of almost every available worldwide fossil:

https://evolutionnews.org/2024/03/fossil-friday-new-dating-of-pleistocene-fossils-rewri...

"They re-dated the earliest occurrences of Homo sapiens in Africa, the Levant and Europe, and confirm that “if Apidima 1 is indeed a H. sapiens, it documents the earliest known presence of our species in Eurasia with an estimated age of about 211 thousand years, while the Misliya cave material from Israel “still represents the earliest known derived H. sapiens in the Levant” with an age of 152 thousand years”. Both dates are much earlier than the traditional Out-of-Africa scenario would predict to find.

***

"...they provided an updated summary of our present understanding of human evolution, with remarkable admissions such as the “co-existence of multiple lineages (in our view, species) over the last 2 million years, with at least 4 of these persisting into the last 100,000 years”, or that studies “show that searching for deep single points of origin for lineages like H. sapiens may ultimately be a futile task.”

"However, the most important take-home message is shown in figure 85...It shows that several different alleged species of the genus Homo lived contemporary in the Pleistocene and experienced various instances of gene flow. This strongly suggests to me and some other critics of the current consensus that all these assumed species are just different populations of a single species Homo sapiens, that at best would qualify as subspecies or geographical races. I will provide a detailed argument for such reclassification in a book-length treatment of archaic Homo that is currently in preparation.

"The most recent data on human fossils and their dating do not really support an evolutionary narrative from ape-like ancestors to modern humans, but a gap between ape-like australopithecines and real humans, as well as just a very diverse human species that even featured a greater morphological and genetic diversity in the past than today. Darwin critics with a Biblical perspective may find it interesting that this would resonate quite well with population genetic models based on a first pair with designed heterozygotic diversity and a significant population bottle neck (Sanford et al. 2018, Hössjer & Gauger 2019)." (my bold)

Comment: this is Bechly from a very ID viewpoint. The references just above are ID science articles. I've reviewed the enormous study he has used for his commentary. Generally, they used advanced dating techniques to show most fossils wee older than originally dated. Note my bold. Either they are not available, or the fossil gap between Australopithecus and real humans exists as true history. Such a gap literally demands a designer, just as the Cambrian gap does.

origin of humans; a new massive analysis

by David Turell @, Sunday, April 28, 2024, 18:48 (87 days ago) @ David Turell

The original study:

https://www.nature.com/articles/s41559-024-02390-z

"Abstract:
The search for drivers of hominin speciation and extinction has tended to focus on the impact of climate change. Far less attention has been paid to the role of interspecific competition. However, research across vertebrates more broadly has shown that both processes are often correlated with species diversity, suggesting an important role for interspecific competition. Here we ask whether hominin speciation and extinction conform to the expected patterns of negative and positive diversity dependence, respectively. We estimate speciation and extinction rates from fossil occurrence data with preservation variability priors in a validated Bayesian framework and test whether these rates are correlated with species diversity. We supplement these analyses with calculations of speciation rate across a phylogeny, again testing whether these are correlated with diversity. Our results are consistent with clade-wide diversity limits that governed speciation in hominins overall but that were not quite reached by the Australopithecus and Paranthropus subclade before its extinction. Extinction was not correlated with species diversity within the Australopithecus and Paranthropus subclade or within hominins overall; this is concordant with climate playing a greater part in hominin extinction than speciation. By contrast, Homo is characterized by positively diversity-dependent speciation and negatively diversity-dependent extinction—both exceedingly rare patterns across all forms of life. The genus Homo expands the set of reported associations between diversity and macroevolution in vertebrates, underscoring that the relationship between diversity and macroevolution is complex. These results indicate an important, previously underappreciated and comparatively unusual role of biotic interactions in Homo macroevolution, and speciation in particular. The unusual and unexpected patterns of diversity dependence in Homo speciation and extinction may be a consequence of repeated Homo range expansions driven by interspecific competition and made possible by recurrent innovations in ecological strategies. Exploring how hominin macroevolution fits into the general vertebrate macroevolutionary landscape has the potential to offer new perspectives on longstanding questions in vertebrate evolution and shed new light on evolutionary processes within our own lineage."

Another commentary:

https://www.discovermagazine.com/the-sciences/human-ancestors-may-have-bucked-an-evolut...

"In evolution, competition is thought to be a zero-sum game. One species adapts and survives. Another doesn’t and dies off. A new study in Nature Ecology & Evolution posits that human ancestors might be an exception.

"Conventional wisdom in evolutionary theory has held that climate has driven the rise and fall of various hominin species. In most vertebrates, interspecies competition also plays an important role. That role has been discounted in human ancestors, according to the study.

“We have been ignoring the way competition between species has shaped our own evolutionary tree,” said Laura van Holstein, a University of Cambridge archeologist and author of the paper, in a press release. “The effect of climate on hominin species is only part of the story.”

***

"Van Holstein found that in many early hominins — as in other mammals — separation into other species increases, then flatlines, at which point extinction rates start to ramp up.

"But when she looked at the later “Homo” groups of hominins, van Holstein noticed a finding she called bizarre. Her analysis showed that competition between Homo species appeared to result in even more species.

"'This is almost unparalleled in evolutionary science," van Holstein said.

"Her analysis explains why the hominin fossil record can sometimes appear uneven. Several more hominin species than previously assumed were likely co-existing, and potentially competing. She added that the fossil record, by itself, can’t fully explain separation into species, because it relies somewhat upon chance — the finding of a particular fossil that pinpoints a particular species to a certain time and place.

“'The earliest fossil we find will not be the earliest members of a species,” said van Holstein.

"So why the divergence? Later Homo sapiens became ecosystem engineers, according to the paper. Learning how to make and use tools and to build fires gave later species adaptive benefits that could improve quicker than any evolutionary change.

“'Adoption of stone tools or fire, or intensive hunting techniques, are extremely flexible behaviors,” van Holstein said. “A species that can harness them can quickly carve out new niches, and doesn’t have to survive vast tracts of time while evolving new body plans.'”

Comment: simple reasons we dominated. We outsmarted all of them!! Human exceptionalism, of course!

origin of humans; cave dwellers not hunters

by David Turell @, Monday, April 29, 2024, 19:16 (86 days ago) @ David Turell

These folks were content to gather veges with little hunting:

https://www.sciencenews.org/article/stone-age-humans-gatherer-hunter

"Unlike many of their mostly meat-eating peers, a group of late Stone Age hunter-gatherers living in what is now northeastern Morocco had a largely plant-based diet. But despite dining for millennia on local, wild plants — such as acorns, pistachios and wild oats, the Iberomaurusians never started cultivating those plants. The finding aligns with recent challenges to scientists’ theory that heavy reliance on plants ultimately leads to their domestication (SN: 11/9/21).

"Before humans figured out farming, they relied on hunting and gathering to sustain themselves, with most protein coming from animals. Over time, they shifted from foraging to cultivating certain plants, eventually leading to the plants’ domestication — so goes the typical story of agriculture’s emergence. Archaeologists once assumed that the Iberomaurusians also relied mostly on animals. But data from human remains at a site in Morocco points to a predominantly plant-based diet, researchers report April 29 in Nature Ecology & Evolution.

"The site — called Taforalt, which is located in a cave — is a “very important site to study human evolution and understand human behavior during this time,” says Zineb Moubtahij, an archaeologist at Géosciences Environment Toulouse, a research laboratory in France. The Iberomaurusians lived around this area for a long time, starting around 23,000 years ago. They used part of the cave to bury the deceased.

***

"The analysis showed that the Iberomaurusians’ diets were closer to that of herbivores, suggesting a heavy reliance on plants not animals. The group wasn’t completely vegetarian; meat was still on the menu, Moubtahij says. But compared with other hunter-gatherers from this time, the Iberomaurusians’ diet leaned more on the gatherer side and less on the hunter side.

"Previous work has suggested that the Iberomaurusians loved their plant foods, says Teresa Steele, a paleoanthropologist at the University of California, Davis not involved in this study. In 2014, researchers analyzed the decayed teeth of some Iberomaurusians. Their frequent cavities indicated a diet rich in starchy, fermentable foods. But it’s “always nice to see further verification of things we have less direct evidence about,” she says.

"Curiously, the group relied on wild plants for many millennia without ever domesticating them. The archaeological record suggests the plants’ features didn’t change over time.

"That’s in contrast with humans in southwestern Asia, who began farming around 12,000 to 11,000 years ago (SN: 7/4/13). It wasn’t until around 7,600 years ago that agriculture arrived in what is now Morocco, and the farmed plants had been brought from other lands. Why the Iberomaurusians’ reliance on plants didn’t lead to domestication is a mystery, Moubtahij says.

"Because there are relatively few well-preserved human remains from around this time in history — the late Pleistocene — scientists have limited evidence to piece together how agriculture arose in different places. “It’s really important that we have these sort of studies that show us that there were alternative pathways and food production systems,” says Michael Westaway, an archaeologist at the University of Queensland in Australia who was not involved in the work. One thing is clear: “Not all roads lead to agriculture.'”

Comment: necessity drives use. If one had an easy plant diet, why bother to make the effort to hunt? There are, obviously, a variety of human activities that described our evolution.

origin of humans; Denisovans in New Guinea

by David Turell @, Monday, May 13, 2024, 16:55 (72 days ago) @ David Turell

In Papua:

https://www.livescience.com/health/genetics/papua-new-guineans-genetically-isolated-for...

"Papua New Guineans, who have been genetically isolated for millennia, carry unique genes that helped them fight off infection — and some of those genes come from our extinct human cousins, the Denisovans.

"The research also found that highlanders and lowlanders evolved different mutations to help them adapt to their wildly different environments.

"New Guineans are unique as they have been isolated since they settled in New Guinea more than 50,000 years ago," co-senior study author François-Xavier Ricaut, a biological anthropologist.

"Not only is the predominantly mountainous terrain of the island country particularly challenging, but infectious diseases are also responsible for more than 40% of deaths.

"Locals therefore had to find a biological and cultural strategy to adapt, which means that the population of Papua New Guinea is a "fantastic cocktail" to study genetic adaptation, Ricaut said.

"Modern humans first arrived in Papua New Guinea from Africa around 50,000 years ago. There, they interbred with Denisovans who'd been living in Asia for tens of thousands of years. As a result of this ancient interbreeding, Papua New Guineans carry up to 5% Denisovan DNA in their genomes.

***

"They found that mutations lowlanders probably inherited from Denisovans boosted the number of immune cells in their blood. The highlanders, meanwhile, evolved mutations that raised their red blood cell count, which helps reduce hypoxia at altitude. That's not unusual, as people from several other high-altitude environments have evolved different mutations to combat hypoxia.

"The Denisovan gene variants may affect the function of a protein called GBP2 that helps the body fight pathogens that are only found at lower altitudes, such as the parasites that cause malaria. These genes may therefore have been selected during evolution to help people fight off infection at lower altitudes where pathogens are rife, the team said.

Comment: from Siberia to New Guinea, the Denisovans covered Asia. No full-sized fossil so far, only DNA traces.

origin of humans; early human hunting weapons

by David Turell @, Thursday, May 16, 2024, 18:00 (69 days ago) @ David Turell

Found only in Germany:

https://www.sciencealert.com/ancient-humans-crafted-deadly-wooden-weapons-300000-years-...

"Powerful new imaging techniques reveal humans were already crafting complex hunting weapons from wood 300,000 years ago, upending the stereotype of the Stone Age.

"Archeologists have previously suspected humans have been using wooden tools for at least as long as stone ones, but due to wood's more fragile nature, most evidence has rotted away.

"Now, using 3D microscopy and micro-CT scanners to examine 187 wooden artifacts from Schöningen in Germany, archeologist Dirk Leder from the Lower Saxony State Office for Cultural Heritage and colleagues have confirmed the suspicions.

"'Wood was a crucial raw material for human evolution, but it is only in Schöningen that it has survived from the Paleolithic period in such great quality," explains University of Göttingen archeologist Thomas Terberger.

"Amidst this stash of wooden artifacts, the largest known from the Pleistocene (2.58 to 11,700 years ago) were at least 10 spears, seven throwing sticks, and 35 domestic tools. They were all carved from woods known to be both flexible and hard, including spruce, pine, and larch.

"The tools showed clear evidence of a splitting technique previously only known to be used by modern humans, as well as signs of carving, scraping, and abrasion.

"'The way the wooden tools were so expertly manufactured was a revelation to us," exclaims University of Reading paleolithic archaeologist Annemieke Milks.

"Working wood to the discovered level of sophistication is a slow and many-step process, requiring much patience and forethought. What's more, the age of the tools coincides with when Neanderthals were rising to dominance in Europe, outcompeting other early human species.

***

"It turned out that these pre-Homo sapiens had fashioned tools and weapons to hunt big game," Terberger told Franz Lidz at the New York Times. "Not only did they communicate together to topple prey, but they were sophisticated enough to organize the butchering and roasting."

"These powerful hunting abilities are likely much older than the wood artifacts found in Schöningen, the researchers argue. These skills would have ensured early humans had access to high-quality food sources for generations, providing the capacity for this increase in brain growth and associated cognitive skills.

"'Likewise, [hunting] would have ensured sustainable populations even in less favorable parts of Europe during the Pleistocene and contributed to human range expansion across the globe," Leder and team write in their paper.

"Incredibly, the researchers also found evidence of recycling. Tools that had been broken or blunted were reworked for new purposes.

"The study provides unique insights into Pleistocene woodworking techniques," the researchers conclude.

"'Schöningen's wooden hunting weapons exemplify the interplay of technological complexity, human behavior, and human evolution.'"

Comment: This ancient big game hunting requires coordination of actions of a team of folks. They could not have done this without some understandable vocal communications. Not true organized language as we know it, but meaningful grunts and gestures. We think in our language, but I wonder how did they think to invent these weapons, so long ago.

origin of humans; neanderthal sapiens breeding brief

by David Turell @, Tuesday, May 28, 2024, 23:33 (57 days ago) @ David Turell

At a period about 47.000 years ago:

https://www.nature.com/articles/d41586-024-01452-3?utm_source=Live+Audience&utm_cam...

"...a study of hundreds of ancient and modern genomes has pinpointed when the two species began pairing off — and has found that the genetic intermingling lasted for only a short time, at least on an evolutionary scale.

***

"Earlier studies tried to understand this history by comparing contemporary human genomes with a small number of Neanderthal ones. But this approach makes it challenging for researchers to define where Neanderthal sequences in the modern genome start and end.

"To address this challenge, Leonardo Iasi, an evolutionary geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his colleagues analysed 58 individuals who lived between 2,200 and 45,000 years ago and compared their DNA with that of 231 modern individuals of diverse ancestries other than African ones. People of full African ancestry don’t carry substantial amounts of Neanderthal DNA because their forebears were not part of the exodus from the continent while Neanderthals were alive.

"This large-scale, multi-millennia-spanning comparison made it more straightforward to monitor ‘introgression’ of Neanderthal-derived sequences into the modern human genome. The results indicated that Neanderthal-derived genetic contributions in the modern samples could be traced to a single ‘pulse’ of gene flow starting roughly 47,000 years ago — more recently than originally projected —and spanning some 6,800 years, ending around the same time that Neanderthals were nearing extinction. Nearly 7,000 years might seem like a long time, but it is remarkably short on evolutionary timescales considering the sizable changes that the human genome underwent.

"Notably, many of the Neanderthals’ genomic contributions were subsequently removed with remarkable speed from the H. sapiens genome. Modern human genomes contain vast ‘deserts’ that have been fully cleared of Neanderthal remnants — but the authors detected these deserts even in ancient genomes from the latest stages of human–Neanderthal interaction. According to Emilia Huerta-Sanchez, an evolutionary biologist at Brown University in Providence, Rhode Island, this suggests that many Neanderthal sequences could have been detrimental to humans, and were therefore actively and rapidly selected against by evolution.

"Huerta-Sanchez says this work fills important gaps in ancient human history. “One of the strengths of the study is that by incorporating ancient human genomes, they learnt more about how evolutionary forces have shaped Neanderthal variation in human populations,” she says.

"But other gaps remain. For example, ancestral human genomic data from some geographical regions, including Oceania and East Asia, are much scarcer than from western Eurasia. East Asia is particularly intriguing, because modern humans in the region retain especially high levels of Neanderthal DNA — roughly 20% more than do European people."

Comment: the interbreeding had to be fast and furious but seeing different females is always tempting to the male. A designer would not have to help.

origin of humans; tracing early migration patterns

by David Turell @, Wednesday, May 29, 2024, 18:48 (56 days ago) @ David Turell

Using open and riparian areas:

https://phys.org/news/2024-05-environmental-conditions-early-humans-migrated.html

"The Out of Africa theory suggests that more than 70,000 years ago, some groups left Africa to spread across Europe, Asia, Australia, and the Americas. However, it remains unclear how much the environment they encountered beyond Africa facilitated or hindered their journey.

"Researchers combined climate models, genetic data, and archaeological evidence to examine how regional environmental conditions influenced migration and to re-establish our long-lasting connection to nature.

***

"'The first human migrants favored routes that provided essential resources and facilitated travel, as well as regions with a mix of forests and open areas for shelter and food, while allowing them to expand into new territories," Dr. Saltré said.

"In Europe, humans likely first spread from the Fertile Crescent through the Caucasus Mountains into Scandinavia approximately 48,300 years ago and Western Europe around 44,100 years ago, following warmer and wetter conditions.

"In northern Asia, migration routes followed major rivers to cope with harsher climates before reaching Beringia, a currently submerged land bridge between Siberia and Alaska, approximately 34,700 years ago.

"In North America, humans initially migrated along the Pacific coast around 16,000 years ago, and then approximately 3,000 years later, moved inland through the ice-free corridor by the Mackenzie River.

In South America, migration followed wetter grasslands bordering the Amazon, leveraging connectivity provided by major rivers by 14,800 years ago.

***

"He said, "Knowing where people first trekked beyond the cradle of human evolution gives us a flavor of how adaptable our early ancestors were, what environmental challenges they faced, and how they overcame them and survived. We can also infer the technological innovations that were at play during those times—such as watercraft, clothing, and other tools—that allowed people to exploit the most hostile environments.'"

Comment: Why did we migrate? Did we use up the resources to force a move or were we just curious about what was over the next set of hills? This doesn't tell us, but the direction is North and then East, which strongly suggests curiosity.

origin of humans; Neanderthal DNA in humans has no Y

by David Turell @, Monday, June 17, 2024, 17:21 (37 days ago) @ David Turell

Neanderthal sex chromosome Y is missing in humans:

https://www.sciencealert.com/neanderthal-dna-exists-in-humans-but-one-piece-is-mysterio...

"The Homo sapiens genome today contains a little bit of Neanderthal DNA. These genetic traces come from almost every part of the Neanderthal genome – except the Y sex chromosome, which is responsible for making males.

"So what happened to the Neanderthal Y chromosome? It could have been lost by accident, or because of mating patterns or inferior function. However, the answer may lie in a century-old theory about the health of interspecies hybrids.

***

"Scientists have recovered copies of the full male and female Neanderthal genomes, thanks to DNA from well-preserved bones and teeth of Neanderthal individuals in Europe and Asia.

"Unsurprisingly, the Neanderthal genome was very similar to ours, containing about 20,000 genes bundled into 23 chromosomes.

"Like us, they had two copies of 22 of those chromosomes (one from each parent), and also a pair of sex chromosomes. Females had two X chromosomes, while males had one X and one Y.

"Y chromosomes are hard to sequence because they contain a lot of repetitive "junk" DNA, so the Neanderthal Y genome has only been partially sequenced. However, the large chunk that has been sequenced contains versions of several of the same genes that are in the modern human Y chromosome.

"In modern humans, a Y chromosome gene called SRY kickstarts the process of an XY embryo developing into a male. The SRY gene plays this role in all apes, so we assume it did for Neanderthals as well – even though we haven't found the Neanderthal SRY gene itself.

***

"At least half of the whole Neanderthal genome can be pieced together from fragments found in the genomes of different contemporary humans. We have our Neanderthal ancestors to thank for traits including red hair, arthritis and resistance to some diseases.

"There is one glaring exception. No contemporary humans have been found to harbour any part of the Neanderthal Y chromosome.

***

"...maybe the Neanderthal Y was never present in interspecies matings. Perhaps it was always modern human men who fell in love with (or traded, seized or raped) Neanderthal women? Sons born to these women would all have the H. sapiens form of the Y chromosome.

"However, it's hard to reconcile this idea with the finding that there is no trace of Neanderthal mitochondrial DNA (which is limited to the female line) in modern humans.

"Or perhaps the Neanderthal Y chromosome was just not as good at is job as its H. sapiens rival. Neanderthal populations were always small, so harmful mutations would have been more likely to accumulate.

***

"The missing Neanderthal Y may then be explained by "Haldane's rule". In the 1920s, British biologist J.B.S. Haldane noted that, in hybrids between species, if one sex is infertile, rare or unhealthy, it is always the sex with unlike sex chromosomes.

"In mammals and other animals where females have XX chromosomes and males have XY, it is disproportionately male hybrids that are unfit or infertile. In birds, butterflies and other animals where males have ZZ chromosomes and females have ZW, it is the females.

"Many crosses between different species of mice show this pattern, as do feline crosses. For example, in lion–tiger crosses (ligers and tigons), females are fertile but males are sterile.

"We still lack a good explanation of Haldane's rule. It is one of the enduring mysteries of classic genetics.

"But it seems reasonable that the Y chromosome from one species has evolved to work with genes from the other chromosomes of its own species, and might not work with genes from a related species that contain even small changes.

"We know that genes on the Y evolve much faster than genes on other chromosomes, and several have functions in making sperm, which may explain the infertility of male hybrids.

"So this might explain why the Neanderthal Y got lost. It also raises the possibility that it was the fault of the Y chromosome, in imposing a reproductive barrier, that Neanderthals and humans became separate species in the first place."

Comment: it is a mystery looking for an explanation. Presented here as interesting.

origin of humans; Neanderthal interbreeding over more time

by David Turell @, Friday, July 12, 2024, 19:32 (12 days ago) @ David Turell

Latest analysis more than 100 thousand years:

https://www.sciencemagazinedigital.org/sciencemagazine/library/item/12_july_2024/420649...

"A paper this week in Science concludes Neanderthals inherited as much as 10% of their genome from modern humans, including several genes involved in brain development. The Neanderthal-eye view allowed the researchers to date when the two groups mingled, finding they made babies together remarkably early: more than 200,000 years ago, not long after Homo sapiens coalesced as a species. The dalliances were repeated 105,000 to 120,000 years ago, and 45,000 to 60,000 years ago, the ancient Neanderthal DNA suggests. “It argues mating was more common than previously thought,” says Princeton University geneticist Joshua Akey, who led the study.

"This new picture further blurs the boundaries between Neanderthals and modern humans. And it identifies features of the Neanderthal genome suggesting our big-brained, heavy-browed relatives were pitifully rare, which could help explain why they went extinct. “It’s alarming to see how small the Neanderthal populations were—this is a very powerful result,” says paleogeneticist Maanasa Raghavan of the University of Chicago.

"Once seen as a separate species, Neanderthals have enjoyed a complete makeover in the 14 years since researchers first sequenced DNA in their fossils and found they interbred with modern humans. Most living people outside of Africa have inherited about 1% to 2% of their DNA from Neanderthals, perhaps from a prolonged period of mixing 45,000 to 60,000 years ago in Europe or the Middle East.

***

"By analyzing the length and other features of the diverse segments of modern human DNA, Akey and Li could calculate when and how often these ancient hookups happened. The smaller the stretches of DNA, the earlier Neanderthals got them, because inherited segments get shorter over generations.

"The first mating episode the team spotted was very ancient—200,000 to 250,000 years ago, around the time anatomically modern humans first show up in the fossil record in Africa. The team speculates that perhaps some early modern humans crossed the Sahara Desert when the climate was humid, on the trail of antelope, ostrich, and other game, and eventually wandered to the Middle East, where they met the Neanderthals.

"A few tantalizing fossils—a purported modern human skull from Greece and a jaw from Israel—support the idea that modern humans did leave Africa that early. Their lineages died out—but not before they left their mark on the Neanderthals’ genome.

"Akey’s team dated another round of Neanderthal-modern mating to about 105,000 to 120,000 years ago. Researchers speculate those encounters, too, could have happened in the Middle East, because modern humans and Neanderthals are known to have lived in nearby caves at that time. One team even thinks they have found hybrid offspring: The remains of a strange-looking Neanderthal with modern tools dating to 120,00 to 130,000 years ago from the Nesher Ramla quarry in central Israel.

"The third bout of mixing is the familiar one, about 50,000 to 60,000 years ago, likely in the Middle East or Europe, where Neanderthals and modern humans overlapped for thousands of years."

***

"If some of the diverse DNA in Neanderthals came from modern humans, then our cousins had even less genetic diversity than previously thought—and therefore even smaller populations. The study implies Neanderthal numbers dwindled between 250,000 years and 40,000 years ago, and that by the end of their time on the planet, their breeding population was less than 3000, compared with at least 10,000 breeding modern humans, Akey says. Stringer says Neanderthal numbers may have been so small because they mostly lived in northern regions where they were vulnerable to climate change and glaciation.

"People with Neanderthal genes didn’t abruptly vanish, Akey says—their offspring just acquired more and more modern human DNA. “They were overwhelmed by waves of modern humans extending out of Africa,” he says. “The modern human population eventually absorbed the Neanderthals.”

"Even before then, the findings suggest, our ancestors and Neanderthals had more in common than we ever knew. “I think this paper closes the loop in terms of us thinking about ‘us’ versus ‘them,’” Raghavan says."

Comment: By studying Neanderthal DNA for the presence of human DNA the picture of interbreeding becomes clearer and more time expansive.

origin of humans; a place for Sahelanthropus

by David Turell @, Tuesday, July 09, 2024, 21:42 (15 days ago) @ David Turell

An ancestor from seven million years ago:

https://www.newscientist.com/article/2438905-when-did-human-ancestors-start-walking-on-...

"The period between 7 million and 4 million years ago is a bit of a nebulous phase in the story of human evolution. There are basically four data points: Sahelanthropus tchadensis from 7 million years ago, Orrorin tugenensis from 6 million years ago and the two species of Ardipithecus from 5.6 million and 4.4 million years ago. Each is known from a handful of incomplete fossils. For a period of 3 million years, that’s not much. For comparison, there are dozens of Neanderthal sites from the past 500,000 years.

***

"Despite being the oldest known hominin, Sahelanthropus is a relatively recent discovery, first described in 2002 by a group of researchers. The remains were found in the deserts of Chad, which is in north-central Africa, a long way from eastern countries of the continent like Ethiopia and Tanzania that had yielded many famous fossils.

"The main find was a skull, which was named Toumaï... writer Jeff Hecht said it didn’t resemble any modern great ape: “Although its body and brain were the size of a modern chimp’s, its face was quite different, with large brow ridges and much smaller canine teeth.” The researchers also found some teeth and bits of jawbone.


"The French researchers who described Sahelanthropus argued it was bipedal. This was based mainly on the base of the skull and how it apparently fitted onto the spine: it looked like the skull sat directly atop the spinal column, as opposed to being at an angle like in an ape skeleton. It was an intriguing argument – but far from conclusive.

***

"In 2018, the pair tried to present their own analyses of the femur at a conference at the University of Poitiers, but they were blocked by the organisers....

"The following year, Macchiarelli and Bergeret-Medina submitted a paper about the femur... which was finally published in November 2020. The key point was that the Sahelanthropus femur was curved. This is typical of a great ape like a chimpanzee, and not what you’d expect of an upright-walking hominin. Our leg bones are straight because they need to act like pillars supporting the entire weight of our bodies. I consulted two palaeoanthropologists,.. and they both agreed: Sahelanthropus didn’t look like a biped.

"However, the original Poitiers research team, after years of silence, decided to start talking....

"Guy and his colleagues highlighted a number of features of the femur that they say indicate bipedality. For instance, thicker regions along the shaft of the bone correspond to those seen in modern humans and are different from those in great apes. There was also “a rough surface at the top of the femur where the buttock muscles attach”.

***

"The overall message is that the few pieces we have of Sahelanthropus’s limbs don’t show strong evidence of habitual bipedal walking. “It’s generally indistinguishable from the African apes,” says Zanolli.

***

"For now, we can’t even be sure that bipedality evolved in Africa. It’s tempting to think so, because the oldest bipedal hominins we know of are African, even if you discount Sahelanthropus. A study published in May combined the locations of known hominin and ape fossils and their suspected relationships, and concluded that the group that includes both chimpanzees and hominins probably originated in north-central Africa.

"A paper from March suggested that the last common ancestor of hominins and other African apes lived in Eurasia, but that a dramatic event separated the population into two, which then evolved independently.

"What dramatic event? Why, the Zanclean Megaflood of course. If you don’t know, there was a period between about 6 million and 5.3 million years ago when the Mediterranean almost entirely dried out. The Strait of Gibraltar, which connects the Mediterranean to the wider Atlantic, closed – and the sea gradually evaporated, leaving hypersaline lakes. This was the Messinian Salinity Crisis.

"Then, around 5.3 million years ago, the Strait of Gibraltar reopened – and the waters of the Atlantic came rushing in. One reconstruction estimated that it took “from a few months to two years” to refill the Mediterranean basin, which, if not an apocalyptic mega-tsunami, is still pretty fast.

"Supposedly, this Zanclean Megaflood cut off one population of apes/hominins on the Arabian peninsula, while others were able to reach Africa – creating an evolutionary split. In May, a separate group went further and linked the closure and reopening of the Mediterranean to changes in the behaviour of the Pacific tectonic plate.

"You may be able to tell that I’m unconvinced by all of this. It seems to me there are far too many intermediate steps from the Pacific tectonic plate and the Zanclean Megaflood to hominins habitually walking upright, and we can’t be sure about any of them. We don’t even know the timing of the origin of bipedality. If either Sahelanthropus or Orrorin was bipedal, the behaviour evolved well before the megaflood.

"So, much as I want to link the origin of hominins to the biggest flood of the past 10 million years, I think we probably ought to find some more fossils first."

Comment: a low fossil count in this period may mean very small populations of these forms. We obviously evolved from some ape form. The Mediterranean flood is a fascinating event to add to the confusion.

origin of humans; early migration to Iberia

by David Turell @, Saturday, July 13, 2024, 18:27 (11 days ago) @ David Turell

Latest Archeology:

https://phys.org/news/2024-07-geological-dating-techniques-european-hominids.html

"One of the most important controversies about human evolution and expansion is when and by what route the first hominids arrived in Europe from the African continent. Now, geological dating techniques at the Orce sites (Baza basin, Granada) place the human remains found in this area as the oldest in Europe, at approximately 1.3 million years old. These results reinforce the hypothesis that humans arrived in Europe through the south of the Iberian Peninsula, through the Strait of Gibraltar, instead of returning to the Mediterranean via the Asian route.

***

"These new data are very precise thanks to the long sedimentary sequence that outcrops in Orce. "The uniqueness of these sites is that they are stratified and within a very long sedimentary sequence, more than eighty meters long. Normally, the sites are found in caves or within very short stratigraphic sequences, which do not allow you to develop long paleomagnetic sequences in which you can find different magnetic reversals," says Luís Gibert.

"The researchers have been able to identify a magnetic polarity sequence "with five magnetic events that allow them to place the three Orce sites with human presence between the Olduvai and Jaramillo subchron, that is, between 1.77 and 1.07 million years ago (Ma)," says the researcher. Subsequently, they have applied a statistical age model to accurately refine the chronology of the different stratigraphic levels with a margin of error of only 70,000 years.

"The result of this innovative methodology is that the oldest site with human presence in Europe would be Venta Micena with an age of 1.32 Ma, followed by Barranco León, with an age of 1.28 and finally Fuente Nueva 3, with an age of 1.23 Ma. "With these data, the other major site on the peninsula, the Sima del Elefante in Atapuerca, would be relegated to second place, far behind Orce, between 0.2 and 0.4 Ma more modern," adds the researcher.

***

"In this sense, the paper presents a detailed analysis of the micromammals and large mammals from all the Orce sites, carried out by the expert Robert Martin, based on the paleontological collections stored at the Museum of the Catalan Institute of Palaeontology Miguel Crusafont (IPS) in Sabadell.

"'The results indicate that the small and large fauna of Orce is more primitive than, for example, that of the Sima del Elefante, where the evidence shows that the rodent Allophaiomys lavocati is more evolved than the Allophaiomys recovered from the Orce sites," Gibert explains.

"Another relevant indicator of the age of the Orce sites is the absence of the ancestors of the pigs. "These animals are considered to be Asian immigrants and have not been found in any European site between 1 and 1.5 Ma, while they have been found in the Sima del Elefante, supporting that the Orce fauna is older," explains the researcher.

"This new dating would be added, according to the researcher, to other evidence that would tip the balance in favor of the colonization of Europe through the Strait of Gibraltar, rather than the alternative route: the return to the Mediterranean via Asia, such as "the existence of a lithic industry with similarities to that found in the north of the African continent and also the presence of remains of African fauna in the south of the peninsula, such as those of Hippopotamus, found in the sites of Orce, and those of Theropithecus oswaldi, an African primate similar to a baboon, found in the Victoria cave, a site near Cartagena (Murcia), non-existent anywhere else in Europe."

"'We also defend the hypothesis—adds the researcher—that they arrived from Gibraltar because no older evidence has been found at any other site along the alternative route," says Gibert.

"With these results, the researchers point to a "diachronism" between the oldest occupation of Asia, measuring 1.8 Ma, and the oldest occupation of Europe, which would be 1.3 Ma ago, so that African hominids would have arrived in southwestern Europe more than 0.5 Ma after leaving Africa for the first time about 2 Ma ago.

"'These differences in human expansion can be explained by the fact that Europe is isolated from Asia and Africa by biogeographical barriers that are difficult to overcome, both to the east (Bosphorus Strait, Dardanelles, Sea of Marmara) and to the west (Strait of Gibraltar). Humanity arrived in Europe when it had the necessary technology to cross maritime barriers, as happened before a million years ago on the island of Flores (Indonesia)," says Gibert.

***

"'As cited in the paper, we have identified other migrations of African fauna through Gibraltar at earlier times, 6.2 and 5.5 Ma ago when the Strait of Gibraltar was very narrow."

"A total of five human remains were found at the Orce sites since excavations began in 1982 by the paleoanthropologist Josep Gibert. Firstly, two fragments of humerus bitten by hyenas were found at Venta Micena, as well as parts of a cranial fragment consisting of two parietals and an occipital, associated with an abundant Early Pleistocene fauna."

Comment: this paper turns around the theory that humans went East out of Africa and then West. Now it is North, then East.

origin of humans; early migration to Argentina

by David Turell @, Wednesday, July 17, 2024, 20:01 (7 days ago) @ David Turell

22,000-year-old evidence:

https://www.newscientist.com/article/2440063-butchered-bones-hint-humans-were-in-south-...

"Marks found on the 21,000-year-old bones of a giant, armadillo-like animal in Argentina may be the oldest evidence of humans in the southern South America.

"If confirmed through additional excavation and research, the findings could push back the date humans were known to be living in the area by about five millennia, to the end of the last glacial period. That would predate the currently accepted arrival of humans on either American continent by at least 1000 years, says Nicolas Rascovan at the Pasteur Institute in Paris, France.

“'Humans could have been present in South America much earlier than we thought and even earlier than what is assumed of the entry of people in North America,” he says.

"Scientists generally believe that people migrated across the Bering Strait from Asia into North America between 15,000 and 20,000 years ago and then spread down into Central and South America, says Rascovan. However, the proposed dates have stirred significant controversy among experts since the mid-19th century.

"Recently, the apparent discoveries of butchered bones in Mexico from up to 26,000 years ago and jewellery made of giant sloth bones in Brazil from up to 27,000 years ago have made researchers question whether humans reached the Americas much earlier, he says.

***

"Its bones and shells were marked by 32 straight cuts that looked like they had been made by stone tools, given the inner stripes within the grooves and their V-shaped form. Radiocarbon dating placed the specimen in the last glacial maximum, as late as 21,000 years ago.

"Delgado, Rascovan and their colleagues scanned a selection of cut marks and created 3D models for closer analysis. The angles of the entry point of the grooves and the depth of the cuts reflect a pattern that is consistent with butchering of fresh bone, they say.

The bones showed no signs of scrapes from the teeth of carnivores or scavengers. The team’s investigation of the sediment around the bones and shell suggests that the animal parts were buried quickly in partially wet climate conditions like those of the region 21,000 years ago.

***

“'A red flag is the total absence of any associated human-made artefacts with these [bones],” says Potter, adding that the marks might be due to carnivore activity or trampling. “Stone tools and debris are ubiquitous in actual human processing sites.”

"Such evidence may appear as the excavation continues, says Rascovan.

"In the meantime, though, Delgado says his team feels confident about the findings since the marks strongly fit with scientific models of cuts made by human tools and patterns that would be followed during butchering."

Comment: Humans liked to migrate Eastward from Africa, a curiosity about what lay over the ridge.

origin of humans; Denisovan Neanderthal mixing

by David Turell @, Friday, July 19, 2024, 17:36 (5 days ago) @ David Turell

More DNA from the cave:

https://www.sciencemagazinedigital.org/sciencemagazine/library/item/19_july_2024/420769...

“'I’m pleased to tell you about a new Denisovan genome from a 200,000-year-old male,” said Peyrégne, a postdoc at the Max Planck Institute for Evolutionary Anthropology.

"The genetic sequence he unveiled is the oldest high-quality human genome yet—80,000 years older than the previous record holder, a Neanderthal who lived about 120,000 years ago. The results come after more than a decade of effort to find fossilized bones and a second genome of a Denisovan, the mysterious archaic human discovered through its DNA 14 years ago.

***

"The genomes of both Denisovans and the ancient Neanderthal all came from the same cold, fossil-rich site: Denisova Cave in the Altai Mountains of Siberia.

According to the analysis by Peyrégne and colleagues, the newly sequenced male represents a distinct population of early Denisovans that interbred multiple times with a group of Neanderthals whose population had not been detected in DNA before.

***

"Denisovans are primarily known from their DNA. Researchers have the genome of the girl, as well as bits of nuclear and mitochondrial DNA from fragmentary fossils of seven additional individuals, all also from Denisova Cave. Scientists have also identified some Denisovan DNA in living humans, including in Papuans and Han Chinese people, acquired from past interbreeding. DNA in sediments showed that Denisovans were first in the cave 300,000 years ago, and later lived in a cave on the Tibetan Plateau. The scanty fossils—teeth, a toe bone, a rib—reveal this archaic human had larger molars than did the Neanderthals and a robust lower face, known from a jawbone in China. But no one really knows what Denisovans looked like.

***

"The DNA analysis revealed the male Denisovan had inherited 5% of his genome from an ancient, previously unknown population of Neanderthals. The male, labeled Denisova 25, came from a separate population of Denisovans from the girl, known as Denisova 3, and from the other Denisovans in the cave. The girl’s DNA is more closely related to the Denisovan sequences in living modern humans, who got them from at least two Denisovan populations.

"All this suggests the older male’s population was replaced in the cave by later Denisovans, Peyrégne said in his talk. The data also suggest the male Denisovan’s ancestors interbred multiple times with Neanderthals. Denisovans were apparently replaced in the cave by Neanderthals for a period, based on the Neanderthal fossil dated to about 120,000 years ago. By about 60,000 years ago, though, the Denisovans had moved back in. The two groups may even have met in the cave—DNA from a bone fragment from a female dated to more than 50,000 years ago shows her mother was a Neanderthal and her father a Denisovan. Later, both DNA and fossils indicate modern humans occupied the cave and Denisovans and Neanderthals disappear. The region was clearly a crossroads for various types of humans, Peyrégne said in the talk.

***

"Although Denisovans and Neanderthals apparently interbred repeatedly, their lineages are distinct: They diverged from a common ancestor at least 400,000 years ago. The ancestors of Neanderthals settled in Europe and the Middle East, whereas Denisovans headed farther east into Asia where they evolved separately, acquiring roughly 300,000 genetic changes that differentiate them from Neanderthals, according to the new genome. “Neanderthals and Denisovans remain in separate groups,” and mixed at the edges of their geographic ranges, Peyrégne said in his talk.

"In the question and answer period, an audience member asked whether the male’s genome also had DNA from an even older, unidentified type of human—perhaps Homo erectus—whose DNA has been spotted in the Denisovan girl’s genome. “If there is any Denisova superarchaic ancestry, it’s also present in this genome,” Peyrégne responded. “[That DNA] is shared between Denisova 3 and Denisova 25.'” (my bold)

Comment: Note the bold. It is the first evidence of Erectus to Homo as a direct connection, which would indicate Bechly's point that all the other Homo sapiens fossils found are just variations of early sapiens. That the Denisovans and Neanderthals co-habituated means to me they were so similar, they easily lived together.

origin of humans; early migration to southeast Asia

by David Turell @, Tuesday, July 23, 2024, 18:55 (1 day, 9 hours, 18 min. ago) @ David Turell

Recent discoveries:

https://www.sciencedaily.com/releases/2024/07/240719123837.htm

"New evidence of human occupation in southeast Indonesia dating back 42,000 years offers fresh clues on the route taken by some of the first humans to arrive in the region, according to a study from The Australian National University.

"Lead author and ANU PhD candidate Hendri Kaharudin said the location of the discovery -- at Elivavan on Indonesia's Tanimbar islands -- makes it especially significant.

"Tanimbar is located just off the 'Sahul shelf', which encompasses modern-day Australia, as well as New Guinea," he said.

"'The question of how our early ancestors arrived there from Southeast Asia is one of the most captivating in prehistoric migration, mainly because of the vast distances covered and advanced seafaring skills that would have been required.

"'There are two main routes that have been explored as possibilities since the mid-20th century -- a northern path via islands like Sulawesi, and a southern track passing near Timor and the Tanimbar islands.

"'This discovery marks one of the southern route's earliest known sites, making it a crucial piece of the puzzle."

"According to the researchers, while there are still unanswered questions about Elivavan's first inhabitants, the risky nature of the sea crossings suggests the colonists had developed advanced maritime technology by around 42,000 years ago.

"'They would have had to traverse bodies of water exceeding 100 kilometres in distance, regardless of their direction of travel," Mr Kaharudin said.

"'Along with tiny fragments of pottery we also found evidence of things like bones, shells and sea urchins that point to the island's role as a hub for early maritime activities.

"'As more work is done in lesser-explored regions like the Tanimbar islands, I expect we'll uncover more about early human life and migration patterns."

"Mr Kaharudin said it's also clear the colonisation of Sahul was not a single event but "a gradual process involving successive waves of seafaring populations."

"'Coastal communities likely navigated shorelines, exploiting marine resources and establishing resilient settlements along their journey," he said."

Comment: skipping from island makes sense, but raises the question, why leave an island unless its resources dwindled? Or just wanderlust?

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