Friday, September 18, 2015

NOVA: Dawn of Humanity.



The first human? Homo naledi, a new branch of the human family tree. National Geographic.


Dawn of Humanity. Video. NOVA. PBS, September 10, 2015. Also here.

Homo Naledi, New Species in Human Lineage, Is Found in South African Cave. By John Noble Wilford. New York Times, September 10, 2015.

Naledi Fossils: This Face Changes the Human Story. But How? By Jamie Shreeve. National Geographic, September 10, 2015.

Naledi Fossils: Mystery Lingers Over Ritual Behavior of New Human Ancestor. By Nadia Drake. National Geographic, September 15, 2015.



In this artist’s depiction, Homo naledi disposes of its dead in South Africa’s Rising Star cave. Though such advanced behavior is unknown in other early hominins, the scientists who discovered the fossils say no other explanation makes sense. ART BY JON FOSTER. SOURCE: LEEBERGER, WITS



Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. By Lee R. Berger et al. eLife, September 10, 2015.

Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa. By Paul H.G.M Dirks et al. eLife, September 10, 2015.

The many mysteries of Homo naledi. By Chris Stringer. eLife, September 10, 2015.





Wilford:

Acting on a tip from spelunkers two years ago, scientists in South Africa discovered what the cavers had only dimly glimpsed through a crack in a limestone wall deep in the Rising Star Cave: lots and lots of old bones.

The remains covered the earthen floor beyond the narrow opening. This was, the scientists concluded, a large, dark chamber for the dead of a previously unidentified species of the early human lineage — Homo naledi.

The new hominin species was announced on Thursday by an international team of more than 60 scientists led by Lee R. Berger, an American paleoanthropologist who is a professor of human evolution studies at the University of the Witwatersrand in Johannesburg. The species name, H. naledi, refers to the cave where the bones lay undisturbed for so long; “naledi” means “star” in the local Sesotho language.

In two papers published this week in the open-access journal eLife, the researchers said that the more than 1,550 fossil elements documenting the discovery constituted the largest sample for any hominin species in a single African site, and one of the largest anywhere in the world. Further, the scientists said, that sample is probably a small fraction of the fossils yet to be recovered from the chamber. So far the team has recovered parts of at least 15 individuals.

“With almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage,” Dr. Berger said.

The finding, like so many others in science, was the result of pure luck followed by considerable effort.

Two local cavers, Rick Hunter and Steven Tucker, found the narrow entrance to the chamber, measuring no more than seven and a half inches wide. They were skinny enough to squeeze through, and in the light of their headlamps they saw the bones all around them. When they showed the fossil pictures to Pedro Boshoff, a caver who is also a geologist, he alerted Dr. Berger, who organized an investigation.

Just getting into the chamber and bringing out samples proved to be a huge challenge. The narrow opening was the only way in.

Paul Dirks, a geologist at James Cook University in Australia, who was lead author of the journal paper describing the chamber, said the investigators first had a steep climb up a stone block called the Dragon’s Back and then a drop down to the entrance passage — all of this in the total absence of natural light.

For the two extended investigations of the chamber in 2013 and 2014, Dr. Berger rounded up the international team of scientists and then recruited six excavating scientists through notices on social media. One special requirement: They had to be slender enough to crawl through that crack in the wall.

One of the six, who were all women and were called “underground astronauts,” was Marina Elliott of Simon Fraser University in British Columbia. She said the collection and removal of the fossils involved “some of the most difficult and dangerous conditions ever encountered in the search for human origins.”

Besides introducing a new member of the prehuman family, the discovery suggests that some early hominins intentionally deposited bodies of their dead in a remote and largely inaccessible cave chamber, a behavior previously considered limited to modern humans. Some of the scientists referred to the practice as a ritualized treatment of their dead, but by “ritual” they said they meant a deliberate and repeated practice, not necessarily a kind of religious rite.

“It’s very, very fascinating,” said Ian Tattersall, an authority on human evolution at the American Museum of Natural History in New York, who was not involved in the research.

“No question there’s at least one new species here,” he added, “but there may be debate over the Homo designation, though the species is quite different from anything else we have seen.”

A colleague of Dr. Tattersall’s at the museum, Eric Delson, who is a professor at Lehman College of the City University of New York, was also impressed, saying, “Berger does it again!”

Dr. Delson was referring to Dr. Berger’s previous headline discovery, published in 2010, also involving cave deposits near Johannesburg. He found many fewer fossils that time, but enough to conclude that he was looking at a new species, which he named Australopithecus sediba. Geologists said the individuals lived 1.78 million to 1.95 million years ago, when australopithecines and early species of Homo were contemporaries.

Researchers analyzing the H. naledi fossils have not yet nailed down their age, which is difficult to measure because of the muddled chamber sediments and the absence of other fauna remains nearby. Some of its primitive anatomy, like a brain no larger than an average orange, Dr. Berger said, indicated that the species evolved near or at the root of the Homo genus, meaning it must be in excess of 2.5 million to 2.8 million years old. Geologists think the cave is no older than three million years.

The field work and two years of analysis for Dr. Berger’s latest discovery were supported by the University of the Witwatersrand, the National Geographic Society and the South African Department of Science and Technology/National Research Foundation. In addition to the journal articles, the findings will be featured in the October issue of National Geographic Magazine and in a two-hour NOVA/National Geographic documentary to air Wednesday on PBS.

Scientists on the discovery team and those not involved in the research noted the mosaic of contrasting anatomical features, including more modern-looking jaws and teeth and feet, that warrant the hominin’s placement as a species in the genus Homo, not Australopithecus, the genus that includes the famous Lucy species that lived 3.2 million years ago. The hands of the newly discovered specimens reminded some scientists of the earliest previously identified specimens of Homo habilis, who were apparently among the first toolmakers.

At a news conference on Wednesday, John Hawks of the University of Wisconsin, Madison, a senior author of the paper describing the new species, said it was “unlike any other species seen before,” noting that a small skull with a brain one-third the size of modern human braincases was perched atop a very slender body. An average H. naledi was about five feet tall and weighed almost 100 pounds, he said.

Tracy Kivell of the University of Kent, in England, an associate of Dr. Berger’s team, was struck by H. naledi’s “extremely curved fingers, more curved than almost any other species of early hominin, which clearly demonstrates climbing capabilities.”

William Harcourt-Smith of Lehman College, another researcher at the Museum of Natural History, led the analysis of the feet of the new species, which he said are “virtually indistinguishable from those of modern humans.” These feet, combined with its long legs, suggest that H. naledi was well suited for upright long-distance walking, Dr. Harcourt-Smith said.

In an accompanying commentary in the journal, Chris Stringer, a paleoanthropologist at the Natural History Museum in London, found overall similarities between the new species and fossils from Dmanisi, in the former Soviet republic of Georgia, dated to about 1.8 million years ago. The Georgian specimens are usually assigned to an early variety of Homo erectus.

Much remains to be discovered in the Rising Star Cave, like determining the ages of the fossils and the evolutionary position of H. naledi in the genus Homo and the human family tree. The discovery chamber has not given up all of its secrets. “There are potentially hundreds if not thousands of remains of H. naledi still down there,” Dr. Berger said.

At the news conference in South Africa on Thursday announcing the findings, Dr. Berger said: “I do believe that the field of paleoanthropology had convinced itself, as much as 15 years ago, that we had found everything, that we were not going to make major discoveries and had this story of our origins figured out. I think many people quit exploring, thought it was safer to conduct science inside a lab or behind a computer.” What the new species Naledi says, Dr. Berger concluded, “is that there is no substitute for exploration.”


Is Donald Trump Following in the Footsteps of Andrew Jackson and Ronald Reagan?

Is Donald Trump Another Andrew Jackson? By Alfred J. Zacher. History News Network, September 14, 2015.

Donald Trump Is Reagan’s Heir. By Matthew Pressman. The Atlantic, September 16, 2015.

Donald Trump is brilliant revenge: The GOP’s demise looks a lot like this. By Heather Cox Richardson. Salon, September 8, 2015.


Zacher:

The possibility of Donald Trump becoming the Republican nominee for president and thereafter being elected to that high office elicits an historical perspective. The name that most readily reflects the credentials and character of Donald Trump is Andrew Jackson. The seventh president was not part of the establishment of the Democratic Party that imparted the thoughtful sometimes-scholarly qualities of Jefferson, Madison and Monroe. He was not a member of the Founders. Jackson like Trump was a popular figure of power and success as the general who won the battle of New Orleans. He was a successful lawyer and judge, though known as being hot headed, vulgar and impulsive. He had minimal experience in government serving relatively briefly in the House of Representatives and in the Senate. Jackson entered the political arena at a time of transition and great upheaval in the country. Americans were leaving the comfort of their homes and the country life they knew to work in cities or risking their lives moving to farmlands in the Middle West. This was a rugged, individualistic striving newly enfranchised citizenry who found in the roughhewn outspoken Jackson the personification of themselves. Jackson believed the government was benefiting the wealthy and monopolies to the detriment of the average American.

Jackson clearly represented the views of the majority of electorate during his two terms in office. He met both his and their goal of destroying the Bank of the United States, the institution that carried on some of the functions of the present day Federal Reserve. He and his followers believed the Bank served the wealthy and the monopolies at the expense of the average citizen. Once successful in closing the bank, Jackson established state banks whose easy lending policies led to speculation that ended in a severe depression lasting five years.

Another of his objectives and of the majority of the electorate was the removal of Native Americans from Georgia. Jackson ignored the ruling of the U.S. Supreme Court, which found unconstitutional the State of Georgia law which disposed of all of the property belong to Native Americans. Further, the law ordered them to leave Georgia. Countless thousands of Native Americans were forced to march to the Oklahoma Territory, with many dying along the way.

Andrew Jackson left office a popular president, appearing to have fulfilled the objectives of the rising segment of the population, who were demanding an opportunity to share in the wealth of the nation. They did not blame Jackson for the depression and they were solidly behind the removal of the Native American.

From this historical perspective, the chances of Donald Trump being the Republican nominee and the next president may reside in the degree of discontent there is within the electorate and their belief he has the wherewithal to resolve that discontent.