Posts Tagged ‘Anthropology’

Human evolution as a braided stream rather than a branching tree

January 4, 2014
An interspecies love child? from Nature (Christoph P.E. Zollikofer)

An interspecies love child? from Nature (Christoph P.E. Zollikofer)

The genetic history of modern humans is creating a vast jigsaw puzzle. Genetic evidence is mounting that most people today carry some Neanderthal genes, that some carry what have been labelled “Denisovan” genes, that Denosivans and Neanderthals not only had a common ancestor but that there also was admixture between some Denisovans and some Neanderthals and that there was at least one other as yet unnamed archaic honim which interbred with the Denisovans. It now becomes clear that viewing all these various archaic humans as different species could be wrong. They could all well be the same species.

Chris Finlayson reviews the  paleoanthropology advances during 2013:

The conclusion of the Dmanisi study was that the variation in skull shape and morphology observed in this small sample, derived from a single population of Homo erectus, matched the entire variation observed among African fossils ascribed to three species – H. erectus, H. habilis and H. rudolfensis.

The five highly variable Dmanisi fossils belonged to a single population of H. erectus, so how could we argue any longer that similar variation among spatially and temporally widely distributed fossils in Africa reflected differences between species? They all had to be the same species. 

I have been advocating that the morphological differences observed within fossils typically ascribed to Homo sapiens (the so-called modern humans) and the Neanderthals fall within the variation observable in a single species.

It was not surprising to find that Neanderthals and modern humans interbred, a clear expectation of the biological species concept. …. If the fossils of 1.8 or so million years ago and those of the more recent Neanderthal-modern human era were all part of a single, morphologically diverse, species with a wide geographical range, what is there to suggest that it would have been any different in the intervening periods?

Probably not so different if we take the latest finds from the Altai Mountains in Siberia into account. Denisova Cave has produced yet another surprise, revealing that, not only was there gene flow between Neanderthals, Denisovans and modern humans, but that a fourth player was also involved in the gene-exchange game.

The identity of the fourth player remains unknown but it was an ancient lineage that had been separate for probably over a million years. H. erectus seems a likely candidate. Whatever the name we choose to give this mystery lineage, what these results show is that gene flow was possible not just among contemporaries but also between ancient and more modern lineages.

Just to show how little we really know of the human story, another genetic surprise has confounded palaeoanthropologists. Scientists succeeded in extracting the most ancient mitochondrial DNA so far, from the Sima de los Huesos site in Atapuerca, Spain.

The morphology of these well-known Middle Pleistocene (approximately 400,000 years old) fossils have long been thought to represent a lineage leading to the Neanderthals.

When the results came in they were actually closer to the 40,000 year-old Denisovans from Siberia. We can speculate on the result but others have offered enough alternatives for me to not to have to add to them. The conclusion that I derive takes me back to Dmanisi: We have built a picture of our evolution based on the morphology of fossils and it was wrong.

Some time ago we replaced a linear view of our evolution by one represented by a branching tree. It is now time to replace it with that of an interwoven plexus of genetic lineages that branch out and fuse once again with the passage of time

A braided stream rather than the branches of a tree is the better analogy where  – as John Hawkes describes it:

The “braided stream” analogy captures different information about human origins than the usual branching tree. The branches of a tree do not reconnect with each other above the point where they initially separate. A tree will never admit to exchanging sap between its branches, and there are no little xylem hyphae between branches to carry sap anyway. Our evolution was truly a network in which multiple populations existed and contributed to our process of adaptation.

But the braided stream is not quite satisfactory for the picture that is emerging:

promiscuity in the pleistocene

John Hawkes again:

I admit that the braided stream is not a perfect analogy. Diverging rivulets within a valley almost always come together again, forming a complicated network as they form sandbars and islets. None of them flow into a cul-de-sac. Some human populations of the past did become extinct, they did not inexorably flow back into the mainstream of our evolutionary history. Some of them may have flowed back into the mainstream only through very small channels of genetic exchange. When we go far enough back, some populations really did branch off into their own direction. It’s just not clear yet which populations those were. Maybe an evolutionary swamp would be a better analogy, full of algae-covered bayous.

I like the braided stream, and it’s clear that its time has come. Ancient DNA has begun to show the process of genetic exchange was not a minor player in our evolution. All human populations today evidence some mixture of ancient populations that existed well before the “origin of modern humans”. Genetic exchanges between different populations were dominant in the formation of some human adaptations. Some ancient populations can be understood only as the mixed descendants of other, yet more ancient ones. It’s mixing all the way back.

braided-stream-leone

A braided river from http://cloudman23.wordpress.com/ Image – Yann Arthus-Bertrand

The story will most likely become much more complex – as further pieces of the jigsaw are revealed – before the whole picture can be seen But it is already becoming apparent that the origin of modern humans includes genetic exchange with many “species” supposed to have predated AMH and this exchange was not insignificant.

Perhaps the concept of “Anatomically Modern Humans” has to be expanded and pushed back in time. Rather than an origin some 200,000 years ago the start of “modern humans” could need to be pushed back to about 500,000 years ago and has to somehow bring Neanderthals and Denisovans (and some others) back into the fold.

And maybe our ancestors of 20,000 generations ago were just as shocked at a Denisovan-Neanderthal marriage as some in India are today at an “inter-caste” marriage!

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Another fraudster unmasked in Dutch academia: Anthropologist Mart Bax

September 23, 2013

After the unmasking of the massive scientific misconduct committed by Dirk Smeesters, Don Poldermans and Diedrik Stapel, the Netherlands can ill afford yet another scandal. But that would be living in hope. Now comes this scandal involving an anthropologist, Mart Bax, which appears to be just as massive a fraud.

It does seem that Dutch Universities are cleansing their academic stables. And by the amount of excrement being found it seems to be quite a task! I don’t think that attitudes and pressures in Dutch scientific research are much different to those in other parts of Europe. Which only suggests that while the Dutch are cleaning house, there is a great deal of muck waiting to be found in other countries.

(The picture in the earlier posting was not of Mart Bax but of the journalist who exposed him. The picture has been removed. My thanks to thinkerandtinker for pointing out my error and my apologies to Mr. Frank van Kolfschooten).

Bax retired as a Professor from the Free University (Vrije Universiteit) of Amsterdam in 2003. But for 15 years – at least – he has been making up data. He has invented places where he has claimed to have carried out research, he has made up titles for himself along with claims of non-existent teaching at prestigious universities. Some 64 papers of his 161 claimed publications do not exist.

  • Of the 161 publications claimed by Bax, 64 are non-existent.
  • The book Medjugorje: Religion, Politics, and Violence in Rural Bosnia (1995) mentions a blood feud for which there is no evidence at all. None of the inhabitants of the area are aware of anything like this happening.
  • Shortly after the publication of book mentioned above, Bax acknowledged that he misinterpreted some information, but claimed he did not have the chance to make any rectifications.
  • The commission established he did have the opportunity to rectify these errors at various occasions, yet never did.
  • After the publication of Medjugorje: Religion, Politics, and Violence in Rural Bosnia, Bax referred to the blood feud in three other articles, after he already acknowledged to be aware of the misinterpretation, which the commission labeled as “serious scientific misconduct”.

Retraction Watch: Bax, who studied an Irish town he called Patricksville, a Dutch pilgrimage site he called Neerdonk, and Medjugorje, a Bosnian pilgrimage site, retired from the Free University in 2002. The university began investigating Bax’s work last year after science journalist Frank van Kolfschooten published Ontspoorde Wetenschap (“Derailed science”). In that book, van Kolfschooten raised questions about Bax’s work into an alleged massacre at Medjugorje during the Bosnian War.

 NRC Handelsblad: Again fraud in science is exposed by a university inquiry. Former professor of political anthropology Mart Bax from the Free University has invented research, published nonexistent items put on his list of publications and  committed forgery in university documents. That concludes a commission of inquiry headed by historian Prof. Michiel Baud from the University of Amsterdam.

Volkskrant: The retired professor of political anthropology at the Vrije Universiteit Amsterdam Mart Bax has committed at least 15 years of serious scientific misconduct, forgery and plagiarism itself. That is the conclusion of the inquiry led by historian Michiel Baud in a report released today.  ….

The committee also calls it “very likely” that Bax has made up much of his fieldwork in Brabant and the Bosnian pilgrimage site of Medjugorje from his imagination. But the committee can not formally call it science fraud since Bax insists he was misled by informants themselves. Notes have been destroyed and the informants themselves are untraceable or deceased. The Committee therefore holds it as “serious scientific misconduct “,” deception” and “unethical scientific behavior”.

Noted in passing 21st July 2013

July 21, 2013
map projections galore

Map Projections Galore

More on cartography and map projections.

The linguistic forensics which unmasked JK Rowling as the mystery author Robert Galbraith.

The drop of tar pitch finally fell after 69 years.

Singing in unison in a choir leads to heart beats being synchronised.

The Indian monsoon is almost half-over and rainfall is running 16% above the long term average. In spite of the floods in Uttrakhand this monsoon will probably be classified as a “good” monsoon.

A Viking trading post,  Steinkjer, mentioned in the Norse sagas and dating from 1000 years ago has probably been identified.

The evidence is mounting that there was a pre-Toba expansion Out of Africa and into Asia around 90-100,000 years ago followed by another post-Toba expansion which then went all the way to Australia. The second wave would have mixed with the first wave survivors of the Toba eruption who were probably the first AMH to intermingle with the Denisovans.

The shale gas bonanza continues in the UK and the advantages are being pushed hard even by Bjorn Lomborg.

Noted in Passing 12th January 2013

January 12, 2013

My hope is to make “Noted in Passing” a regular, weekly post but I am not sure if I will have the discipline to maintain it. I shall try to confine myself to 3 topic areas: “Science and Behaviour”, “Engineering and Technology” and “Bad Science”. I’m trying to avoid politics as a topic in its own right but politics may well creep in under “Behaviour”.

Science and Behaviour

Polar bear numbers world-wide are up and here’s  a marvellous image of a polar bear in winter.

polar bear aurora_borealis_3-t2 free

Polar bear and the aurora borealis (from polar bear science)

Some people apparently believe that  too much genetic information could be a bad thing. Virginia Hughes disagrees strongly and I am inclined to agree with her. Genetic sequencing is here to stay and even if interpretation may lead to new challenges and new dilemmas, this genie cannot be stuffed back into the bottle.

Why did our fingers eveolve wrinkles? Was it perhaps to better be able to grip smooth objects?

John Hawks begins his descent through Darwin’s Descent of Man and has posted his “introduction” which is fascinating and – especially for a layman like me – eminently readable. “Experts” in my opinion are those who explain and not those who try to mystify (usually to inflate their own egos).

David McNeil believes that a gesture-speech unity lies at the origins of language but I am not convinced. When speech began – and that is a story in itself – gestures may well have added to man’s vocabulary but I am skeptical as to the role of gesture in the development of language and the grammar associated with language. But what seems obvious to me is that for the origins of speech as well as the origins of language we have to look to the increasing need for communication as the driving force.

In the meantime miR-941 is now being slated as a specific gene that contributed to how early humans developed tool use and language (in contrast to the FoxP2 gene which is thought to be a more general enabler). A study by psychologists claims that language learning begins before birth but I think they jump far too quickly from sound recognition to language learning and the study does not convince.

Recent excavations at an Australian site provides evidence of inhabitation ” certainly” at 41,230 years ago with the dating of charcoal found at the site. However the earliest inhabitation was much older since stone tools were found in deeper layers than the charcoal, but these have yet to be dated. This seems more consistent with the main human expansion Out of Africarabia first happening before Toba.

Even bloggers on the right are questioning the US love affair with semi-automatic weapons but I don’t expect any significant change to the gun laws in the US anytime soon.

Good grief! Greg Laden believes that summer in the Southern Hemisphere must be a sign of global warming. It’s -6°C outside my window right now and its been snowing in Jerusalem and the Lebanon, so I suppose the Northern Hemisphere must be entering a Little Ice Age.

The luminosity of our Sun varies just 0.1% over the course of its 11-year solar cycle. There is, however, a dawning realization among researchers that even these apparently tiny variations can have a significant effect on terrestrial climate. Tony Phillips from NASA comments on  “The Effects of Solar Variability on Earth’s Climate”  issued by the National Research Council.

Engineering and Technology

The technology for drones that today are used to kill could have more peaceful purposes. A Dronenet for a human free package delivery service  is attractive and does not sound so absurd.

Livefist reports that Airbus has beaten out the Russians to win the Indian Air Force’s new generation of  mid-refuelling tankers while Boeing is still going through teething troubles with the 787 Dreamliner.

The pressures on the supply of neodymium, dysprosium, and other rare-earth metals for the manufacture of strong magnets is leading to a surge in the use of nanotechnology to find alternatives.

Bad Science:

  1. Another idiot study about how our fists evolved in response to fighting!  An excellent takedown by  T. Ryan Gregory. “The most impressive thing about this study is that it managed to gain so much attention with so little substance”. 
  2. ChemBark has this update on serial data fabricator Bengu Sezen who has been hired by the Gebze Institute of Technology.
  3. Simon Kuper has some sympathy for Diederik Stapel who now finds himself in an unforgiving Dutch society. His take on the Stapel affaire is in the FT.
  4. The American Psychiatric Association would seem to be in thrall to the pharmaceutical industry as DSM -5 is adjusted to sell more drugs.
  5. John Hawks has a scathing post about Mark Lynas as “someone who had never read a scientific study on the subject, purporting to be an advocate in the popular press, and having his ignorant statements printed widely by multimillion-dollar media organizations” and the shoe fits whether Lynas is pontificating about GMO or global warming.
  6. Further retractions of social psychology papers: “Fraud committed by any social psychologist diminishes all social psychologists” and reinforces the view that social psychology is mainly for headlines and is still a long way from being a science.
  7. Most junior scientists accept academic theft by their advisors as a way of life and only a very few decide to make any noise about it.

DNA evidence shows farming was not indigenous but was imported into Europe from the East

November 10, 2010

A new paper published in PLoS Biology today uses “high precision ancient DNA methods” to  create a detailed genetic picture of one of the first farming communities in Europe (from central Germany) which reveals that this ancient farming population was radically different to the nomadic populations already present in Europe.

Haak W, Balanovsky O, Sanchez JJ, Koshel S, Zaporozhchenko V, et al. (2010) Ancient DNA from European Early Neolithic Farmers Reveals Their Near Eastern Affinities. PLoS Biol 8(11): e1000536. doi:10.1371/journal.pbio.1000536

The hunter-gatherers of Europe it seems did not change rapidly to become farmers. The farmers moved in (invaded?) from the near east and some 8,000 years ago gradually dominated the scene. From Science Daily:

A team of international researchers led by ancient DNA experts from the University of Adelaide has resolved the longstanding issue of the origins of the people who introduced farming to Europe some 8000 years ago. A detailed genetic study of one of the first farming communities in Europe, from central Germany, reveals marked similarities with populations living in the Ancient Near East (modern-day Turkey, Iraq and other countries) rather than those from Europe.

Project leader Professor Alan Cooper, Director of the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, says: “This overturns current thinking, which accepts that the first European farming populations were constructed largely from existing populations of hunter-gatherers, who had either rapidly learned to farm or interbred with the invaders.”

“We have finally resolved the question of who the first farmers in Europe were — invaders with revolutionary new ideas, rather than populations of Stone Age hunter-gatherers who already existed in the area,” says lead author Dr Wolfgang Haak, Senior Research Associate with ACAD at the University of Adelaide. “We have also been able to use genetic signatures to identify a potential route from the Near East and Anatolia, where farming evolved around 11,000 years ago, via south-eastern Europe and the Carpathian Basin (today’s Hungary) into Central Europe,” Dr Haak says.

The Author summary:

The transition from a hunter–gatherer existence to a sedentary farming-based lifestyle has had key consequences for human groups around the world and has profoundly shaped human societies. Originating in the Near East around 11,000 y ago, an agricultural lifestyle subsequently spread across Europe during the New Stone Age (Neolithic). Whether it was mediated by incoming farmers or driven by the transmission of innovative ideas and techniques remains a subject of continuing debate in archaeology, anthropology, and human population genetics. Ancient DNA from the earliest farmers can provide a direct view of the genetic diversity of these populations in the earliest Neolithic. Here, we compare Neolithic haplogroups and their diversity to a large database of extant European and Eurasian populations. We identified Neolithic haplotypes that left clear traces in modern populations, and the data suggest a route for the migrating farmers that extends from the Near East and Anatolia into Central Europe. When compared to indigenous hunter–gatherer populations, the unique and characteristic genetic signature of the early farmers suggests a significant demographic input from the Near East during the onset of farming in Europe.


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