273 replies to this topic

[wjfox]

'Astonishing' fossil ape discovery revealed

6 November 2019

Fossils of a newly-discovered ancient ape could give clues to how and when walking on two legs evolved.

The ability to walk upright is considered a key characteristic of being human.

The ape had arms suited to hanging in the trees, but human-like legs.

It may have walked along branches and even on the ground some 12 million years ago, pushing back the timeline for bipedal walking, say researchers.

Until now the earliest fossil evidence for walking upright dates back to six million years ago.

https://www.bbc.co.u...onment-50305423

 

 

[wjfox]

Secrets of the largest ape that ever lived

 

13 November 2019

 

A fossilised tooth left behind by the largest ape that ever lived is shedding new light on the evolution of apes.

 

Gigantopithecus blacki was thought to stand nearly three metres tall and tip the scales at 600kg.

 

In an astonishing advance, scientists have obtained molecular evidence from a two-million-year-old fossil molar tooth found in a Chinese cave.

 

The mystery ape is a distant relative of orangutans, sharing a common ancestor around 12 million years ago.

 

"It would have been a distant cousin (of orangutans), in the sense that its closest living relatives are orangutans, compared to other living great apes such as gorillas or chimpanzees or us," said Dr Frido Welker, from the University of Copenhagen.

 

https://www.bbc.co.u...onment-50409541

 

 

[wjfox]

Earliest known cave art by modern humans found in Indonesia

Wed 11 Dec 2019 18.00 GMT

Cave art depicting human-animal hybrid figures hunting warty pigs and dwarf buffaloes has been dated to nearly 44,000 years old, making it the earliest known cave art by our species.

The artwork in Indonesia is nearly twice as old as any previous hunting scene and provides unprecedented insights into the earliest storytelling and the emergence of modern human cognition.

Previously, images of this level of sophistication dated to about 20,000 years ago, with the oldest cave paintings believed to be more basic creations such as handprints.

“We were stunned by the implications of this image,” said Adam Brumm, an archaeologist at the Australian Research Centre for Human Evolution at Griffith University. “This was just mind-boggling because this showed us that this was possibly the oldest rock art anywhere on the face of this planet.”

https://www.theguard...nd-in-indonesia

 

 

[wjfox]

[wjfox]

Australopithecine, running from a gigantic Sivatherium.

(Credit: Velizar Simeonovski)

 

 

[Yuli Ban]

In Groundbreaking Find, Three Kinds of Early Humans Unearthed Living Together in South Africa

Scientists studying the roots of humanity’s family tree have found several branches entangled in and around a South African cave.
 
Two million years ago, three different early humans—Australopithecus, Paranthropus, and the earliest-known Homo erectus—appear to have lived at the same time in the same place, near the Drimolen Paleocave System. How much these different species interacted remains unknown. But their contemporaneous existence suggests our ancient relations were quite diverse during a key transitional period of African prehistory that saw the last days of Australopithecus and the dawn of H. erectus’s nearly two-million-year run.
“We know that the old idea, that when one species occurs another goes extinct and you don’t have much overlap, that’s just not the case,” says study coauthor Andy Herries, a paleoanthropologist at La Trobe University in Australia.

[caltrek]

Oldest Ever Human Genetic Evidence Clarifies Dispute Over Our Ancestors

 

https://www.courthou...-our-ancestors/

 

Introduction:

(Courthouse News) — Researchers have made new discoveries about the earliest history of humanity’s family tree, thanks to a brand-new research technique and an 800,000-year-old tooth.

 

In a study published Wednesday in Nature, scientists from the University of Copenhagen reveal a new research method that allows them to study some of the earliest genetic histories of humanity. Using this new method, they studied in deep detail a roughly 800,000-year-old dental fossil from the Gran Dolina cave site in Sierra de Atapuerca, Spain, and learned some interesting truths about humanity’s ancient and sprawling family tree.

 

The discoveries center around Homo antecessor, an ancient human species believed to have thrived largely during the Old Stone Age. Homo antecessor is widely viewed as an integral part to humanity’s early family tree, but its exact placement and connections with other human species, such as Neanderthals and Denisovans, has never been fully explained.

Wednesday’s study, however, helps to fill in much of those gaps.

 

Using a chemical analysis method known as paleoproteomics, researchers examined the proteins found within the enamel of the 800,000-year-old dental fossil. After sequencing and breaking apart the chemical data, scientists found the Homo antecessor was much more closely related to early modern humans than previously believed.

Reconstruction of Homo antecessor skull (Museu d’Arqueologia de Catalunya, Barcelona, Spain)

[caltrek]

Ancient DNA reveals staying power of early people of the Andes

 

https://www.sciencem...ly-people-andes

 

Introduction:

(Science) Some of the world’s more famous and closely examined archaeological sites pepper the hillsides of the Central Andes, documenting an invention of farming and the rise and fall of powerful civilizations such as the Inca. Now, the largest study of ancient human genomes in South America has added a personal touch to the artifacts. The new research reveals who lived there, when they lived, and how they moved around and intermingled. And despite being a heavily studied area, a big surprise emerged: Descendants of early inhabitants persisted even as civilizations came and went.

 

“This paper sheds light on a region that’s home to some of the world’s most intensively studied ancient societies during a particularly dynamic period in its history,” says Jennifer Raff, an anthropological geneticist at the University of Kansas, Lawrence, who was not involved in the work. “Now, we are beginning to understand the biological history as well” as the archaeological history.

 

The Central Andes Mountains, located mostly in today’s Peru, includes coastal and highland regions. The Incas are the most well-known of the ancient civilizations to live there: During their 1000-year reign, until the Spanish conquered them in the mid-1500s, they built an extensive road system and constructed magnificent stone structures, such as Machu Picchu. And they were preceded by several other well-developed societies. The Moche lived there from 200 C.E. to 850 C.E. and are known for having built giant adobe mounds with murals inside. Overlapping partially in time were the Wari, known for fine textiles and terraced agriculture. And there were other groups as well, such as the Nasca and Tiwanaku.

Machu Picchu was built by the Incas, one of several cultures that settled in the Central Andes over thousands of years.

MATTHEW BUTCHER

[caltrek]

Normally, I don't like to feature reviews for books that I have not actually read.  In the case below, I have made an exception.  Even if one does not read the actual book, the review itself is interesting enough to read. I recommend the entire review instead of just the introduction that I have cited.

 

 

How did ancient cities weather crises?

 

https://www.nature.c...586-020-02070-5

 

Introduction:

(Nature) For millennia, cities have generated power, wealth, creativity, knowledge and magnificent buildings. They have also incubated hunger, violence, war, inequality and disease — as we’ve so painfully experienced this year. The coronavirus pandemic has shaken our faith in urban life, as lockdowns have emptied streets that are home to more than half the world’s population. Basic supply networks have been revealed as fragile, and the densely packed social groups that are engines of income, support and enjoyment have become a source of peril.

 

As the pandemic forces us to contemplate the future of cities — three-quarters of the world’s people could live in urban areas by 2100 — historian Greg Woolf examines their past.

[wjfox]

Earliest evidence for humans in the Americas

1 hour ago

Humans settled in the Americas much earlier than previously thought, according to new finds from Mexico.

They suggest people were living there 33,000 years ago, twice the widely accepted age for the earliest settlement of the Americas.

The results are based on work at Chiquihuite Cave, a high-altitude rock shelter in central Mexico.

Archaeologists found thousands of stone tools suggesting the cave was used by people for at least 20,000 years.

https://www.bbc.co.u...onment-53486868

[Erowind]

If people were in Mexico 33,000 years ago it only reasons they were in North America in general even earlier. Given they'd had to have crossed over from Russia.

[caltrek]

Ancient microbial arms race sharpened our immune system—but also left us vulnerable

 

https://www.sciencem...t-us-vulnerable

 

Introduction:

(Science) At a recent symposium on the evolution of infectious diseases, University of California, San Diego (UCSD), pathologist Nissi Varki noted that humans suffer from a long list of deadly diseases—including typhoid fever, cholera, mumps, whooping cough, measles, smallpox, polio, and gonorrhea—that don’t afflict apes and most other mammals. All of those pathogens follow the same well-trodden pathway to break into our cells: They manipulate sugar molecules called sialic acids. Hundreds of millions of these sugars stud the outer surface of every cell in the human body—and the sialic acids in humans are different from those in apes.

 

Varki and an international team of researchers have now traced how evolution may have scrambled to construct new defenses after that molecular vulnerability emerged in our distant ancestors. By analyzing modern human genomes and ancient DNA from our extinct cousins, the Neanderthals and Denisovans, the researchers detected a burst of evolution in our immune cells that occurred in an ancestor of all three types of human by at least 600,000 years ago.

 

As the researchers report in the current issue of Genome Biology and Evolution, these genetic changes may have sharpened the body’s defenses against the pathogens that evolved to exploit sialic acids—but created new vulnerabilities. In an added irony, they note, humans’ distinctive sialic acids were themselves once a defense against disease. The evolutionary saga is a vivid illustration of the competition between humans and microbes, says microbiologist Christine Szymanski of the University of Georgia, Athens, who is not a co-author. “This gives us a human perspective on how we have to keep changing to keep pace.”

 

The arena for this evolutionary arms race is the glycocalyx, a sugar coating that protects the outer membrane of all cells. It consists of a forest of molecules that sprout from the cell membrane. The sialic acids are at the tip of the tallest branches, sugar chains called glycans, which are rooted to fats and proteins deeper in the membrane.

The influenza A virus, shown in a stylized scanning electron microscopic image, is one of many pathogens that take advantage of a 2-million-year-old evolutionary change in the surface of the human cell in order to slip inside it.

MEDICALRF/SCIENCE SOURCE

[caltrek]

Smallpox and other viruses plagued humans much earlier than suspected

 

https://www.nature.c...586-020-02083-0

 

Introduction:

(Nature) The death date of smallpox is clear. After killing more than 300 million people in the twentieth century, it claimed its last victim in 1978; two years later, on 8 May 1980, the World Health Assembly declared that the variola virus, which causes smallpox, had been eradicated. But the origins of this devastating virus are obscure. Now, genetic evidence is starting to uncover when smallpox first started attacking people.

 

Humans as far back as AD 600 carried variola, an international research team reported this week1 after years of fishing for viral DNA in ancient human remains. The analysis also implies that the virus was circulating in humans even earlier: at least 1,700 years back, in the turbulent period around the fall of the Western Roman Empire, when many peoples were migrating across Eurasia.

 

The research pushes DNA evidence of smallpox back by a millennium. In 2016, researchers had dated it to the seventeenth century, using DNA extracted from a Lithuanian mummy2. “We’ve shown that 1,000 years earlier, during the Viking Age, variola was already quite widespread in Europe,” says Martin Sikora, an evolutionary geneticist at the University of Copenhagen and a member of the team.

 

Smallpox is only the latest example of a serious infectious disease whose history has been suddenly and substantially rewritten by ancient-DNA analysis in the past decade. Earlier this year, a study3 reported that the measles virus — thought to have emerged in humans around the ninth century — might have jumped to people in the first millennium BC, which is when its sequence seems to have diverged from the related (and now-eradicated) rinderpest virus, which infected cattle. In 2018, Sikora’s team showed that hepatitis B had been infecting humans since the Bronze Age, 5,000 years ago4; in 2015, the team reported a similarly early origin for the plague, which is caused by the bacterium Yersinia pestis5.

[caltrek]

How Neanderthals lost their Y chromosome

 

https://www.sciencem...ir-y-chromosome

 

Introduction:

(Science) Neanderthals have long been seen as uber-masculine hunks, at least compared with their lightweight human cousins, with whom they competed for food, territory, and mates. But a new study finds Homo sapiens men essentially emasculated their brawny brethren when they mated with Neanderthal women more than 100,000 years ago. Those unions caused the modern Y chromosomes to sweep through future generations of Neanderthal boys, eventually replacing the Neanderthal Y.

 

The new finding may solve the decade-old mystery of why researchers have been unable to find a Neanderthal Y chromosome. Part of the problem was the dearth of DNA from men: Of the dozen Neanderthals whose DNA has been sequenced so far, most is from women, as the DNA in male Neanderthal fossils happened to be poorly preserved or contaminated with bacteria. “We began to wonder if there were any male Neanderthals,” jokes Janet Kelso, a computational biologist at the Max Planck Institute for Evolutionary Anthropology and senior author of the new study.

 

But in a technical breakthrough, Max Planck graduate student Martin Petr designed a set of probes that used the DNA sequence from small chunks of modern men’s Y chromosomes to “fish out” and bind with DNA from archaic men’s Y chromosomes. The new method works because the Neanderthal and modern human chromosomes are mostly similar; the DNA probes also reel in the few basepairs that differ.

 

The researchers probed the fragmentary Y chromosomes of three Neanderthal men from Belgium, Spain, and Russia who lived about 38,000 to 53,000 years ago, and two male Denisovans, close cousins of Neanderthals who lived in Siberia’s Denisova Cave about 46,000 to 130,000 ago. When the researchers sequenced the DNA, they got a surprise: The Neanderthal Y “looked more like modern humans’ than Denisovans’,” Kelso says.

 

This was a “puzzle,” Petr says, as earlier studies showed the rest of the Neanderthal nuclear genome is a closer match for Denisovans. That suggests the two groups diverged from modern humans about 600,000 years ago. But the appearance of the unusual Y chromosome parallels another genetic takeover: Neanderthal remains dating from 38,000 to 100,000 years ago contain the maternally inherited mitochondrial DNA (mtDNA) of a modern human woman, instead of the ancient Neanderthal mtDNA found in earlier fossils. In that case, an early H. sapiens woman likely interbred with a Neanderthal man more than 220,000 years ago and their descendants carried the modern mtDNA.