Friday, November 24, 2017

New Jebel Irhoud Date Causes Rethink of Chinese Dali Skull

Newsweek (Yes, that Newsweek) has a story on the reexamination of the Chinese Dali cranium, in light of the revised dates for the Jebel Irhoud skulls.  Kastalia Medrano writes:
Known as the Dali skull, it was discovered nearly 40 years ago in China’s Shaanxi province. It belonged to a member of the early hominin species Homo erectus. Its facial structure and brain case are intact, despite being dated to around 260,000 years ago. The Dali skull is so old that archaeologists initially didn’t believe it could share features with the modern Homo sapiens.

But Xinzhi Wu of the Chinese Academy of Sciences in Beijing believed that due to the overwhelming physical similarities, Homo erectus must have shared DNA with Homo sapiens. After decades of this idea being dismissed by mainstream academia, Wu and a colleague, Sheela Athreya of Texas A&M University, recently reanalyzed the Dali skull and found it may force us to rewrite our evolutionary history after all. It’s incredibly similar to two separate Homo sapiens skulls previously found in Morocco. “I really wasn’t expecting that,” Athreya told New Scientist.

If we’d found only the Moroccan skulls, and not the Dali skull, it would make sense to keep believing all modern humans evolved in Africa. But the similarities show that early modern humans may not have been genetically isolated from other parts of the world, like what we know today as China.

“I think gene flow could have been multidirectional, so some of the traits seen in Europe or Africa could have originated in Asia,” Athreya told New Scientist.
Okay, now the nuts and bolts.Dali has always been thought to occupy that rarified space between Homo erectus  and early modern Homo sapiens.  It was always thought to be between 200 and 250 kya, and optically-stimulated luminescence dating (a variant of thermoluminescence) places it between 258 and 267 kya.  My analyses of the skull suggested that it was, in no way, shape or form, a modern human but it did not tend to cluster with the Neandertals in terms of head shape.  Athreya and Wu have done an extensive multivariate analysis and conclude (from the article, likely behind a paywall:
When just the facial skeleton is considered, Dali aligns with Middle Paleolithic H. sapiens and is clearly more derived than African or Eurasian Middle Pleistocene Homo. When just the neurocranium is considered, Dali is most similar to African and Eastern Eurasian but not Western European Middle Pleistocene Homo. When both sets of variables are considered together, Dali exhibits a unique morphology that is most closely aligned with the earliest H. sapiens from North Africa and the Levant.

These results add perspective to our previous view of as Dali a “transitional” form between
Chinese H. erectus and H. sapiens. Athough no taxonomic allocation is appropriate at this time for Dali, it appears to represent a population that played a more central role in the origin of Chinese H. sapiens. Dali's affinities can be understood in the context of Wu's Continuity with Hybridization scenario and a braided-stream network model of gene flow. Specifically, we propose that Pleistocene populations in China were shaped by periods of isolated evolutionary change within local lineages at certain times, and gene flow between local lineages or between Eastern and Western Eurasia, and Africa at other times, resulting in contributions being made in different capacities to different regions at different times.
In combination with the Xuchang remains, the reanalysis of this skull suggests that, indeed, there is a long and complex interrelationship between different hominin groups that dates back some 400 thousand years. From the paper:
In the braided-stream network model, evolutionary change in China was the result of a shifting network of gene flow among distinct regional Chinese populations, as well as between Chinese and Western Eurasian populations. These were not isolated evolutionary lineages; gene flow both within China and between Eastern Eurasia, Western Eurasia and Africa was intermittent and could explain the similarities in aspects of the neurocranium found here between Dali and Western Eurasian Middle Pleistocene humans. Gene flow would best be described as a braided stream network with periods of isolated evolutionary change within a local lineage at times, and periods of gene flow between local lineages or paleo-demes at other times, resulting in contributions being made in different capacities to different regions at different times.
It is pretty clear that our simplistic models of Recent African Replacement and Multiregional Evolution need to be reworked. It is becoming more apparent that what we are looking at either a polytypic species with a huge geographical range or a syngamion of related species that intermixed regularly. The Xuchang skulls were, apparently, not unique.

Thursday, November 23, 2017

Flat Earth Convention in North Carolina

Nuts, I wish I could have gone to this. Stephanie Pappas, at Live Science writes:
A conference aimed at disputing the idea that the world is round just wrapped up in North Carolina.  The first-ever 2017 Flat Earth International Conference (FEIC) was held in Raleigh on Nov. 9 and 10, featuring some of the big names in round-Earth denial. Among the speakers were Darryle Marble, who once took a level on a plane to "prove" the Earth doesn't curve; Mark Sargent, the creator of the Flat Earth Clues YouTube Series, who believes all life is enclosed in a "Truman Show"-like dome structure; and Jeran Campanella, a YouTube and online radio personality, who makes flat-Earth, 9/11 Truther and other conspiracy theory videos. [7 Ways to Prove the Earth Is Round]
Apparently, it was quite a smorgasbord of conspiracy theoreticians.  It is always great fun to see how the science is twisted and one can never quite tell if they are serious or not. 

Wednesday, November 22, 2017

ID Supporter Has Wikipedia Page Erased

Okay, this is just snotty.  Günter Bechly is a palaeontologist who was at the State Museum of Natural History in Stuttgart, Germany.  Recently, Dr. Bechly came out in favor of Intelligent Design.  For this crime, he has had his Wikipedia erased.  According to David Klinghoffer, at Evolution and Science Today (used to be Evolution News and Views):
Our distinguished paleontologist colleague Günter Bechly was erased from Wikipedia after he came out as a proponent of the theory of intelligent design. That, in turn, was after he had already been pushed out of his curator role at the State Museum of Natural History in Stuttgart, Germany, for the same reason. The editors at Wikipedia obscured their treatment of Günter, a world-class expert on dragonflies, by claiming his heresy on ID had nothing to do with the decision to excise him. Instead, they innocently proclaimed that it was due to the realization that he isn’t “notable” enough for the online encyclopedia.

I’ve already pointed out the problems with this contention, and noted that the editors of Bechly’s page and of the grossly distorted Intelligent Design page itself make little effort to hide the ideological axes they grind. There’s little mystery about what happened to Dr. Bechly, or to another ID advocate, Walter Bradley at Baylor University, whose Wiki entry was shredded to near nothing. This is one way the scientific consensus on evolution is maintained, by threatening dissenters. For a scientist, having your accomplishments erased is the ultimate punishment. Wiki editors meanwhile indulge atheist nobodies with extensive biography entries.
Aside from Klinghoffer's usual histrionic bluster about silencing people who disagree with “Darwinism,” (Ken Ham, Henry Morris, John Morris, Stephen Myer, Michael Behe and, yes, even Klinghoffer, himself, have Wikipedia pages) the timing is very suspicious.  Additionally, if you thought he was well-known enough to have a Wikipedia page, why is he suddenly not so?  His page needs to be restored. This just makes Wikipedia look bad and smacks of censorship.

Sunday, November 19, 2017

Neandertal to Modern Transition Full of Fits and Spurts

New evidence suggests that Neandertals survived longer on the Iberian peninsula than elsewhere in Europe.  The redating of the Zafarraya Neandertal from the late 20k's to between 38 and 40 ky saw a revision of theories about Neandertal extinction. Now more evidence has been unearthed suggesting that this window is more secure.   From The Statesman:
Neanderthals may have survived at least 3,000 years longer than thought in what is now Spain – much after the species had died out everywhere else, a study has found.

The findings suggest that the process of modern human populations absorbing Neanderthal populations through interbreeding was not a regular, gradual wave-of-advance but a “stop-and-go, punctuated, geographically uneven history.”

Over more than ten years of fieldwork, researchers excavated three new sites in southern Spain, where they discovered evidence of distinctly Neanderthal materials dating until 37,000 years ago.

“Technology from the Middle Paleolithic in Europe is exclusively associated with the Neanderthals,” said Joao Zilhao, from the University of Barcelona in Spain.

“In three new excavation sites, we found Neanderthal artefacts dated to thousands of years later than anywhere else in Western Europe,” said Zilhao, lead author of the study published in the journal Heliyon.
It seems pretty clear now that the model of rapid replacement of Neandertals does not hold. This kind of evidence, along with sites such as Lagar Velho, suggest that the transition, at least in this region was long-term, with much hybridization.  We still do not know exactly how long Neandertals persisted in this region.  It makes perfect sense that they would have been the last ones to undergo the transition (however that happened) because the earliest Aurignacian sites, associated with modern humans, occur in far eastern Europe as the wave of moderns came through during the Würm I/Würm II interglacial.

The question that I have is why didn't the earliest modern humans, represented by the Jebel Irhoud remains, come through the Strait of Gibraltar?  North of that, all you find are archaic, all the way down to the Zafarraya remains.  I wonder why this is.

Monday, November 13, 2017

And, Apparently, The Stolen Bone is Only One Problem...

The journal Nature is reporting on a scandal of sizable proportions involving a site of early human occupation in Europe.  Ewen Callaway reports:
Serious concerns have surfaced about three research papers claiming evidence for one of the earliest human occupations of Europe.

In an extraordinary letter posted to the preprint server on 31 October1, archaeologists allege that the papers, published in 2013, 2016 and 2017, included material of questionable provenance, and that results reported in the 2016 paper were based on at least one stolen bone. Editors at the journals concerned are publishing expressions of concern about the papers.
The bioRxiv paper is available from the site and, since it is a preprint server, is accessible to anyone wishing to read the story. Here is the bombshell from the paper:
A series of recent papers on the Early Pleistocene palaeontological site of Untermassfeld (Germany) makes claims that are of great interest for studies of earliest Europe and are at odds with the described pattern: the papers suggest that Untermassfeld has yielded stone tools and humanly modified faunal remains, evidence for a one million years old hominin presence in European continental mid-latitudes, and additional evidence that hominins were well-established in Europe already around that time period. Here we evaluate these claims and demonstrate that these studies are severely flawed in terms of data on provenance of the materials studied and in the interpretation of faunal remains and lithics as testifying to a hominin presence at the site. In actual fact any reference to the Untermassfeld site as an archaeological one is unwarranted.
The site is said to have been occupied beginning around a million years ago, which was an astounding claim when it was made.  Critical, however, is that, despite the wealth of archaeological, taphonomic, faunal and floral evidence from the site, there have never been any hominin remains found. 

The article is lengthy but is a fascinating account of a palaeontological mystery and sleuthing.  If the accusations are true, it is blow for the study of early human European occupation and puts a stain on the whole proceedings. 

Thursday, November 09, 2017

Ken Ham Comes to Alberta

Young earth creationism is ubiquitous in home school curricula here in the United States.  Ken Ham is trying to make that the case in Canada, as well.  There has been pushback. Bill Kaufmann of the Calgary Herald writes:
Australian-born Ken Ham, a leading Christian fundamentalist proponent of creationism over evolution, is scheduled as a keynote speaker at the Alberta Home Education Association (AHEA) convention in Red Deer next April.

Ham spearheaded the building of a Noah’s Ark-centred creationist museum in Kentucky, and the educational books he’s authored includes Dinosaurs of Eden: Did Adam and Eve live with dinosaurs?

“Those who believe that only the uneducated reject evolution perhaps do not realize that evolution, far from fact, does not even qualify as a theory,” states an entry on his Answers in Genesis website.

“Evolution is a belief system about the past.”

It also offers a line of textbooks in areas of biology, geology and “creation apologetics.”
This is total nonsense. I would quote Todd Wood at this point, but he is probably tired of me quoting him. Suffice it to say, evolution is one of the most well-tested theories on the planet.  If you choose not to “believe” it, that is fine but to say that it is not a theory is just ignorant and foolish.  The more Ken Ham writes, the less I think he knows about how science works.   And now the pushback:
But Alberta Liberal Leader David Khan said while home schoolers have every right to invite speakers like Ham, it raises questions about what those children are being taught as science.

“None of that belongs in science curriculum, which should be mandatory for everyone regardless of whether they’re funded by Alberta Education or not,” said Khan.

“Having a bunch of kids lacking in basic science education is a problem for society writ large.”

He questioned whether Education Minister David Eggen is doing enough to ensure real science is being taught outside conventional classrooms.

While the AHEA doesn’t receive provincial funding, they’re expected to teach fact-based science, said Eggen’s spokeswoman Lindsay Harvey.

“All students, no matter what format of education they receive, are expected to learn from the current Alberta curriculum,” said Harvey.
I am generally not in favor of government oversight in home schooling. When that happens, you tend to get an agenda that seems to be tolerant of everything except “conservative” values.  Having said that, I wonder about all of these kids who wind up going to secular universities and having their faith blown apart by grounded, empirical science.  You can't mandate to homeschoolers what they should and should not teach unless you force a specific curriculum on them but stories like this shine a spotlight on home schooling that might be detrimental in the long run.

I wonder if Ken Ham is even aware of the damage that he is causing.  As Joel Edmund Anderson put it in his book The Heresy of Ham:
I believe that the paranoia, divisiveness, and frustration that the young earth creationist movement fosters wherever it goes should serve as an indication that there is something fundamentally wrong with it. This is not simply a case of Christians having a difference of opinion on a certain topic.  This is a case of a movement willing to declare war on everyone, Christian and non-Christian alike, who does not capitulate to what they have unilaterally declared to be true.
I couldn't agree more.