Category: anthropology

Readers’ fieldwork pictures

January 15, 2018 • 8:45 am

I’ve put up posts before from Dorsa Amir, a graduate student in biological anthropology at Yale. Here’s her latest contribution: a set of photos from her fieldwork (more photos here). Dorsa’s notes are indented:

As an anthropologist, one of my goals is to explore human behavioral variation across diverse contexts. In conjunction with the larger Shuar Health & Life History project, I have had the amazing opportunity to work with the Shuar, a population indigenous to the Ecuadorian Amazon. The Shuar are forager-horticulturalists who still hunt, fish, and cultivate crops for most of their subsistence, and largely function as small-scale societies. Working with communities of people still living in many ways like their ancestors has been an eye-opening experience when pondering human evolution and culture change. One of the most salient differences between their way of life and ours, in my experience, has been the resilience and independence of Shuar children, who furnish many of their own calories, care for their siblings, and live a much more independent life than their Western counterparts. (I’ve written a bit more about this in a piece for Nautilus). Below are some photos from several summer fieldwork trips.

Note the tamarin:

In the spirit of wildlife photos, here’s Shuar woman with her pet kinkajou [Potos flavus]:

Dorsa had an orange and white cat named Emerson, but wants us to know she’s expanded the felid family to include Hamilton (“Hammy”), named after the late evolutionary biologist W. D. Hamilton. Here’s the happy couple:

 

Nature paper suggests humans inhabited North America 130,000 years ago

April 27, 2017 • 5:43 pm

by Greg Mayer

As Jerry noted yesterday, in a new paper in Nature, Steven R. Holen and colleagues report finding the remains of a butchered 130,000 year old mastodon in San Diego. (If you haven’t already done so, do go take a look at Jerry’s post, which includes a video press release, and illustrations from the paper.)

The key words in the first sentence are ‘butchered’* and ‘San Diego’. The first word indicates that people had taken the bones of the 130,000 year old mastodon apart– which in itself would be a “neat, but what’s the fuss” result. It’s ‘San Diego’ that’s the cause of the fuss. The peopling of the Americas has been a contentious topic for some time, but virtually all the debate has concerned a relatively slim time interval– 12-30 kya (see here for a previous discussion at WEIT, and this news piece in Science about two recent papers with contrasting conclusions). The San Diego find is thus 100,000 + years earlier!

So what evidence do they have for this early arrival? First, they have the mastodon, whose bones were fractured in ways which they find inconsistent with damage by carnivores or the environment, but which appear consistent only with being struck with implements. They did a lot of breaking of elephant bones in order to try to simulate the damage to the mastodon, and concluded that tools alone could do the trick. The mastodon’s remains were radiometrically dated at 130.7 ± 9.4 kya. In addition to the mastodon, they also found stone tools, which they interpret as hammerstones and anvils.

These results would have many important implications for human evolutionary history; but first we must ask, are the results correct?

I must admit I’m dubious. The anvil and hammerstones are not the sorts of objects which are unquestionably manufactured– they are not like finely fluted spear points, whose human origin cannot be doubted. The breakage patterns in the bones do indicate that the breaks occurred perimortem, but I’m not sure the breaks could not be due to non-human causes. The dating is directly on the mastodon, which is good– they’ve not dated some possibly extraneous item which could have been redeposited from earlier strata. But, nonetheless, dating is subject to various artifacts.

As Carl Sagan used to say, “Extraordinary claims require extraordinary evidence.” What makes the current claim extraordinary is that there’s no other evidence of human presence in the Americas for ca. 100+ K years after this find. And it’s not like the late Quaternary of America is an unstudied or poorly known stretch of time! I don’t regard fracture patterns and crude tools to be sufficiently extraordinary evidence to overcome, in a single go, the weight of that 100,000 year absence. It is much more reasonable to think that the new data can be reconciled with all the past data in a way that does not require us to discount the past data. And, thinking, “they must have made a mistake somewhere with the new data”, is a perfectly plausible way of reconciling the two. This conservatism in the face of anomalies is a key part of the method of science– it properly proportions belief to the evidence.

On the other hand, the new data do not threaten to overturn any fundamental principles, merely a seemingly well-attested fact of evolutionary history, and such facts have been overturned before. So, we must ask, but what if they’re right?

The most interesting implication, to me, is that if there were people here 130 kya, they went completely extinct.  It means that human habitation of an entire hemisphere is an iffy thing. The real first Americans got wiped out by something– disease, predators, climate, competitors, whatever. Who would these now extinct people have been? Well, if they got to America not too long before the radiometric date, they would probably be Neanderthaloid (by which I mean the varied archaic Eurasian subspecies of Homo sapiens with which anatomically modern humans interbred after their spread from Africa). If they came much earlier, they might have been Homo erectus (which would make Harry Turtledove’s A Different Flesh, in which the first European settlers of America encounter not Indians, but “sims“, prophetic!).

There would also be a possibility that these first Neanderthaloid Americans survived, and that the anatomically modern human colonizers of ca. 20 kya, interbred with them in the course of replacing them, just as their forebears did in Asia. However, because American Indians are not, as far as I know, enriched for Neanderthaloid alleles relative to other Eurasians (who are 1-4% Neanderthaloid; a bit higher in Melanesia), this seems unlikely. (There are claims out there that Indians are enriched for Neanderthaloid genes, but I don’t know how that got started; East Asians, from which, at least generally, American Indians descend, are Neanderthaloid enriched relative to Western Europeans, which seems to indicate more than one episode of interbreeding on the course of their migration from Africa.)

* I use “butchered” here in the sense of “processed for eating”, as the bones were presumed broken apart to get at the marrow. The paper uses “butcher” in the narrower sense of “cut with a knife or similar implement”. The paper does not say the mastodon was cut with a knife or other sharp tool.

Holen, S. R., T. A. Deméré, D. C. Fisher, R. Fullagar, J. B. Paces, G. T. Jefferson, J. M. Beeton, R. A. Cerutti, A. N. Rountrey, L. Vescera, and K. A. Holen. 2017. A 130,000-year-old archaeological site in southern California, USA. Nature 544:479-483.

The evolution of sexual dimorphism in humans: Part 2

December 21, 2016 • 11:00 am

In a post one week ago, “The ideological opposition to biological truth,” I argued that sexual dimorphism for body size (difference between men and women) in humans is most likely explained by sexual selection, and that it also reflects behavioral differences between males and females: males compete for females, and greater size and strength give males an advantage. That competition results from females—in many species, not just ours—being a “scarce” resource for males, since the number of males capable of breeding far exceeds the number of females who cannot breed because they’re tending offspring or in gestation. This disparity can be categorized in two ways:

  • The behavioral operational sex ratio: the ratio of sexually active males to fertilizable females at a given time. This is about 11.7 in humans!
  • The physiological operational sex ratio, the same ratio but for all individuals capable of reproducing (rather than those actually engaged in mate-hunting). This is about 8.6 in humans.

The ratios are greater in some primates (gorillas have values of about 84!), but if they’re greater than 1, there’s room for sexual selection, since there are more males seeking females than there are females available as mates. This itself is one bit of evidence for the operation of sexual selection in humans.

Now how the sexual selection actually operated in our ancestors is not perfectly clear. Some of it, as the data suggest, involves male-male competition: fights between males to control females, as we witness in gorillas, deer, and elephant seals. Females are more or less constrained to mate with the winning males. Or females may prefer to mate with the biggest and strongest males, for those males may protect their offspring—and hence the female’s genes—better than do smaller, weaker males. (This gives an evolutionary advantage to those females who can discern and choose the best males.)

Both of these factors can, of course, work at the same time, and there are other more arcane forms of sexual selection I won’t mention, including other signs in males of “good genes”. But any sexual-selection scenario goes along with a difference in sexual behavior, explaining why, even today, males are more promiscuous and willing to mate than are the choosier females.

A further possibility is that there could be an ecological distinction between males and females, with males hunting, and thus needing size and strength, while females do gathering (presumably females don’t have time to hunt because they’re rearing children). That doesn’t involve sexual selection, but it also fails to explain all the data, like the correlation between sexual dimorphism and polygyny within humans, and the fact that in our primate relatives there’s not only the same correlation among species, but no palpable division of labor among males and females. It also doesn’t explain the existence of traits like beards, lower voices, or same-sex aggression among human males but not females. Nevertheless, there’s no reason why several forces couldn’t work together to cause men to have evolved larger body size and increased musculature (as well as other features) in our ancestors. But surely sexual selection is one, for the evidence below fits no other hypothesis.

As I noted, these relatively uncontroversial ideas about sexual selection (not mine, actually; they’re the conventional wisdom among evolutionists beginning with Darwin), was challenged by Holly Dunsworth, an associate professor of anthropology at the University of Rhode Island, on her website. Dunsworth, who called my theory (supported by lots of data cited in my original post) a “story”, offers her own speculations, which really are a story because they lack empirical support and don’t explain a lot of observations. Here’s what she said:

It’s not that Jerry Coyne’s facts aren’t necessarily facts, or whatever. It’s that this point of view is too simple and is obviously biased toward some stories, ignoring others. And this particular one he shares in this post has been the same old story for a long long time.

What about the other side of the body size sexual dimorphism story?

What about the women?

Selection could well be the reason they stop growing before men and why they end up having smaller bodies than men, on average.

Perhaps men can make babies while growing, but perhaps women can’t. Energetically, metabolically. So reproduction wins over growth. We reach sexual maturity and stop growing. Is that just a coincidence?

Why doesn’t this (and other tales) fit alongside the big-aggressive-males-take-all explanation for sexual dimorphism? #evolution

But as I noted in the piece she criticized, selection on females—through either evolution of female preference or on differential ecological roles between the sexes—could affect sexual dimorphism. But Dunsworth conveniently ignored that bit. Her criticisms were echoed by an article by Jesse Singal in New York Magazine, which claimed, as did Dunsworth, that I was offering mere “stories”—unevidenced speculation. Singal said this:

In Dunsworth’s view, all she is asking for is some nuance and, well, skepticism. “People love to boil complex processes down to their preferred (intentional or not) story,” she wrote, “with some in leading roles and others completely absent, and we don’t have to take that anymore.” Her tweeted example about growth nicely captures this: It could be that Coyne’s aggressiveness story leaves out important details about why men are bigger than women, or fails to explain certain aspects about that differences. Overall, it certainly seems like people are quicker to latch onto evo-psych stories that reinforce certain views of men and women.

That last sentence is a veiled accusation that my piece was sexist. I reject that completely.

As I noted in part I of this response, neither Singal nor Dunsworth appreciated that I have a long published history of criticizing “just-so” stories in evolutionary psychology. I don’t like unevidenced speculation when it’s promoted as truth. But the sexual selection theory for human sexual dimorphism is supported by a lot of evidence. It is manifestly not a mere “just-so” story.  In my original piece I adduced this evidence (revised slightly):

  • In human societies studied by Richard Alexander, those societies that are more polygynous (in which males compete more intensively for females) show greater sexual size dimorphism than societies that are more monogamous. This was a prediction made before the data were acquired—a prediction derived from sexual selection theory. And it was fulfilled. UPDATE: I see now that Alexander’s finding wasn’t reproduced in another experiment, so consider this conclusion questionable.
  • Among species of primates, there’s a good correlation between the polygyny of a species and sexual dimorphism: those species in which males have a higher variance in offspring number, and in which males thus compete more intensely for females, also show a greater ratio of male/female body size, even when corrected for phylogeny. (Too, in primate species in which males fight each other over females, the relative size of the canine teeth, used in battle, is larger than in species showing less direct male-male competition.)
  • In humans, as in many other species in which males compete for females, the sex ratio at birth favors males. They then die off at a higher rate due to higher risk-taking and exploratory behavior, and also senesce faster, which is why among older humans there are so many more females than males. (Check out any Gray Line tourbus.) This is predicted by sexual selction theory.
  • In line with the above, in humans and other primates, males show from the outset great exploratory and risk-taking behaviors, and as adults show many other behaviors that differ from those of females, such as greater dispersal. Is this due to the Primate Patriarchy? Probably not, given that these differences in behavior are shown in many species besides ours and make evolutionary sense.

There’s more evidence, too, which I’ll mention shortly.

But what’s the evidence for Dunsworth’s theory? As far as I can see, there isn’t any. Her theory claims that 1) females can’t reproduce while growing, while males can. 2) There’s a tradeoff between growth and reproduction, so if you stop growing as a female, you can start reproducing earlier. Conclusion: females stop growing before males because reproduction is all-important, and therefore they’re smaller than males as adults.

But the data don’t even support her theory. Puberty begins in females at about ages 10 and 11, and in males between 11 and 12.  (The age of both appears to be decreasing in recent years.) Yet males keep growing this whole period and well beyond, as do females. There’s no indication that females stop growing when they become reproductively competent. Here are growth curves (stature and weight) for both males and females. Stature begins tapering off at about ages 14-15 in both sexes (a slower taper in males), but both sexes continue to grow until age 20.

Females:

growth-2-20-girls

Males:growth-2-20-boys

Now we don’t know about body sizes and ages of puberty in our ancestors, which is the really important information, and I doubt we’ll have that given that it’s virtually impossible to ascertain the age of puberty in fossils. But clearly there’s no support in any data for Dunsworth’s hypothesis that “perhaps men can make babies while growing, but perhaps women can’t. Energetically, metabolically.” Both men and women can make babies while they’re still growing. But men continue to grow not only faster but also bit longer than do women (see above), something which explains sexual dimorphism. But since men are reproductively competent when they hit puberty, why do they keep getting bigger? Dunsworth doesn’t tell us, but sexual selection theory does. Men achieve greater stature and muscle mass by both growing faster than females, and tapering off a bit later.

So Dunsworth’s hypothesis is not only unsupported by data, but fails to explain the growth data that do exist.

More important, her theory doesn’t explain the four points given above—points that are well explained by sexual selection theory.  She and New York Magazine fail to realize that the sexual-selection explanation for human sexual dimorphism is not a “story”, but makes supported predictions and clarifies previously obscure observations. How irritating to see these people distort what we know about evolutionary theory and human biology!

As I mentioned in earlier posts, I think Dunsworth is blinkered by her ideology, because she thinks that sexual selection theory ignores females. Well, straight male-male competition without female choice does involve evolution mainly in males, but there are forms of sexual selection that involve female choice, too, and that has surely happened in species like birds and fish. In those groups, and others, males show ornaments and colors not useful in male-male competition, but are the object of female choice. And some of that process may have happened in our own lineage. The competing theories are not zero-sum, so that only one can be right. All these processes can work together. But surely one is sexual selection.

Regardless, sexual selection as an explanation implies that there are also sexual differences in behavior: differences we see in modern experiments and are probably not purely cultural because a. they’re predicted by the differences in body size and b. we see the same difference in mate choosiness in many other species—and not just primates. It’s an ineluctable consequence of the difference in reproductive investment between males and females.

I’ll now list some other observations about human mating and morphology that are explained by sexual selection theory but not explained at all by Dunsworth’s theory. Some of these come from the references given at the bottom of the post.

  • In other sexually dimorphic primates, including chimpanzees and gorillas, direct contests between males can be observed, and probably existed in our ancestors since paleoanthropological data show that many more males were killed by violence than females, possibly reflecting inter-group battles, which in modern hunter-gatherer societies are often over females. Many societies also show “bride theft”, capture of females by bands of males—common in Amazonian hunter-gatherer societies.
  • Male humans have more robust skulls than do females, including mandibles and brow ridges. This may reflect evolution to withstand blows to the head. (Males also have a higher tolerance for pain.)
  • Men are not only taller and heavier than women, but are stronger, particularly in the upper body. While size differences are about 8%, and body mass about 15-20%, women’s bodies have a higher percentage of fat, so that when you look at fat-free body mass, men are 40% heavier, have 60% more lean muscle mass, 80% greater arm muscle mass, 75% more upper-body muscle mass, and 50% more lower body mass. This difference in relative amount of muscle mass cannot be explained by Dunsworth’s theory, which is purely about growth, but is explained by male-male competition under sexual selection—and perhaps by female preference as well. This is reflected in differential athletic performance, and is why men and women usually compete separately in athletics. Even for men and women of equal sizes, men are far stronger; as Hill et al. note, “the average man is stronger than 99.9% of women (some of this, of course, may be because men work out; I haven’t checked the references.)
  • In every society studied, men are physically more aggressive than women, both in play as kids and as adults. The vast majority of murderers are men, and this aggressive activity peaks during men’s peak reproductive years, when they would be competing for mates most strongly. These data do not include killings in war.
  • Traits like beards and lower voices in men (men’s vocal folds are 60% longer than women’s, giving them lower voices) have been shown to act as indicators of dominance; both are evolved morphological traits. (The evidence supporting all these claims can be found in the papers cited below.) Women also prefer larger men and deeper voices, so there may have been an element of female choice in sexual selection, though of course the observations we make are on modern rather than ancient hominins.
  • Sexual dimorphism is also seen in our ancestors like Australopithecus and H. erectus, implying that it’s been acting on our lineage a long time. But there’s also some evidence, cited by Plavcan, that the degree of sexual dimorphism has waxed and waned as females got either bigger or smaller over time, implying that there may have been some separate natural selection in females that could increase or decrease sexual dimorphism (but never effaced it).
  • Finally, Buss’s article and others not cited outline the psychological and behavioral differences between males and females that make sense under sexual selection. These not only include the greater promiscuity of males than females, but also the greater sexual jealousy of males toward women than vice versa (our male ancestors weren’t always sure who the father of their mate’s children was, while women were far more certain). There is also a big difference between males and females in their attitudes towards casual sexual experiences (guess in which direction), and in how exacting their standards are for a short-term mate (guess again). Men have lower psychological thresholds for risk-taking. And so on. As Buss wrote, “Large sex differences appear reliably for precisely the aspects of sexuality and mating predicted by evolutionary theories of sexual strategies.”

I’ve adduced about a dozen pieces of evidence supporting the sexual selection explanation for human morphological and behavioral dimorphism—none of which can be explained by Dunsworth’s hypothesis. (And that hypothesis was dead in the water anyway, contradicted by the known data.) Since all hypotheses must, at bottom, be supported by the weight of accumulated scientific evidence, it is clear that sexual selection, and male-male contest competition in particular, is a compelling explanation for human sexual dimorphism. In contrast, Dunsworth’s hypothesis isn’t in the least compelling. That doesn’t mean we shouldn’t keep evaluating the evidence or suggesting new hypotheses, but simply that these should be supported by data rather than ideological preference.

I urge readers to look at the papers below, and use the data (and that from other papers) to evaluate theories about human behavioral and sexual dimorphism. I don’t propose to engage in a dialogue with Dr. Dunsworth about this, but I would like to know how her theory can explain the dozen-odd observations given above.

Dunsworth must have emitted something like twenty tweets about her piece, impugning me; and she even issued this over-the-top pronouncement:

Well, there’s fighting material above, but I’ve had my say. Still, I can’t believe that simply my writing a post on human sexual dimorphism and its implications would drive anybody away from studying human evolution. After all, the give-and-take of hypotheses, critical thinking, and data are the very meat of science, and if you disagree with somebody, you don’t simply walk away from a field. I sure as hell am not leaving evolutionary biology because Dunsworth and New York Magazine took out after me!

2028_4_16

UPDATE: Things are getting worse: Peter Boghossian is arguing with Dunsworth on Twitter (I’m not involved, as I avoid Twitter Wars), but now we’re getting lumped with some rather unsavory types (except for the “evolutionists”):

h/t: Steve, David

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Buss, D. M. 1995. Psychological sex differences. Amer. Psychologist 50:164-168.

Hill, A. K., D. H. Bailey, and D. A. Puts. 2017. Gorillas in our midst? Human sexual dimorphism and contest competition in men. pp. 235-249 in: On Human Nature: Biology, Psychology, Ethics, Politics, and Religion. in M. Tibayrencand F. J. Ayala (eds.) .On Human Nature, M.  Tibayrenc and F. J. Ayala, eds. Academic Press.

Puts, D. A. 2010. Beauty and the beast: mechanisms of sexual selection in humans. Evolution and Human Behavior 31:157-175.

Plavcan, J. M. 2012. Sexual size dimorphism, canine dimorphism, and male-male competition in primates. Where do humans fit in? Human Nature 23:45-67.

A MOOC on Homo floresiensis, the “hobbit” hominin

November 15, 2016 • 10:00 am

I just want to let you know about a new Massive Open Online Course (MOOC) on Homo floresiensis that reader Dermot C. called to my attention. As you may recall, new dating methods have shown that this 3.5-foot diminutive hominin died out about 50,000 years ago rather than the 12,000 originally posited, and arrived in Flores (Indonesia) between 700,000 and 1,000,000 years ago. Also, new specimens have been found, making it pretty clear that the original specimen wasn’t a malformed or diseased individual, but was a member of a real and very tiny hominin species. (Their brains were about the size of those in modern chimps.)

Their phylogenetic relationship to modern H. sapiens isn’t yet clear (they haven’t been able to get good DNA from the remains), but it is clear the species went extinct without leaving descendants, like the “robust” hominins in Africa. They may have well have been descendants of Homo erectus that evolved a small size for reasons unknown.

Here’s the skinny from Dermot’s email:

I thought your readers might be interested in this free MOOC:

“Homo floresiensis uncovered: the science of ‘the Hobbit'”

The course concerns the discovery of Homo floresiensis, ‘the Hobbit’, discovered on Flores island in 2003. It started on 7th November but it is not too late to catch up. The aim of the course is to ‘discover the incredible world of ‘the Hobbit’ as modern archaeological science uncovers secrets hidden in time…Investigating a range of multidisciplinary approaches and techniques, we explore the contributions of modern archaeological science in challenging assumptions about human evolution and exposing secrets hidden in time.

This course has been developed by the Centre for Archaeological Science (CAS) at theUniversity of Wollongong in association with the Indonesian National Research Centre for Archaeology (ARKENAS), and Lakehead University, Canada.’

The course leader is Prof. Bert Roberts, the Director of the Centre for Archaeological Science at the University of Wollongong and an Australian Research Council Laureate Fellow. He was one of the archaeologists involved in excavations where Homo floresiensis was discovered. The Educator is Professor Zenobia Jacobs, Director of the Luminescence Dating Laboratory at the University of Wollongong and an Australian Research Council Future Fellow. And the Mentor is Alyce Mason, an Educational Designer and researcher from the University of Wollongong.

The course lasts 4 weeks at 2 hours per week, although one can spend more time at it.

Anything for the Brits and Yanks to forget about Brexit and Trump!

Here’s a cast of a H. floresiensis cranium from Wikipedia (note the small brain case):

800px-homo_floresiensis

and where H. floresiensis remains were found.

800px-id_-_flores

If you ever get a chance to go to the Smithsonian’s Hall of Human Evolution in Washington D.C. stand next to the reconstructed skeleton of this species and see how incredibly tiny they were. No wonder they were called “hobbits”!

Here’s a reconstructioncompared to a modern human female:

homo_floresiensis_with_modern_human

New study suggests a single miscreant, Charles Dawson, created the “Piltdown Man” hoax

August 11, 2016 • 8:30 am

The story of the fraudulent skull known as “Piltdown Man” is well known. In 1912, lawyer and amateur archaeologist Charles Dawson turned up at the London Natural History Museum with a specimen he claimed to have found at a site in Sussex. He and Arthur Smith Woodward, the head geologist at the Museum, further excavated the site and turned up more bone fragments, including bits of a skull, teeth, jawbones, and even a piece of carved bone—an “artifact” of human devising.

Woodward reconstructed the “skull” and announced with Dawson that the skull, jawbone, and two molar teeth constituted the “missing link” between apes and humans: a 500,000-year old specimen they named Eoanthropus dawsoni. Dawson later reported finding an “intermediate” canine tooth at the site, as well as similar teeth and skull bits (“Piltdown II”) from a site 3 km away. The bones were darkly stained, matching the gravels at the site.

Here’s a reconstruction of the Piltdown Man (Piltdown I), with the original bits in brown and the rest added to fill in the gaps:

piltdown-skull_2416562b

Subsequent findings of genuine early hominins marginalized this fossil (Austalopithecus africanus was described in 1924), but many still believed that E. dawsoni was real. (There were, however, many doubters from the outset.) That lasted until 1953, when scientists showed beyond doubt that “Piltdown Man” comprised, as some had surmised, skull bits from modern humans combined with a recent ape jaw (likely an orangutan), with the ape teeth filed down to look intermediate between those of apes and humans. The jaw, as well as a modern human skull, had been artificially stained, and fossils of other species had been planted at the Sussex locality, along with a bogus “artifact” (probably an elephant bone carved with a steel knife) to give credibility to the fossils. By 1955, after a second publication, Piltdown Man was universally rejected as a hoax.

Yet some creationists still tout the early acceptance of Piltdown Man as evidence for the credulity of scientists who accepted a fake simply because they wanted to believe in human evolution. That doesn’t wash, though, in light of the doubts that accompanied the fossil’s original discovery, the subsequent uncovering of the duplicity by scientists (not creationists), and the dozens of genuine hominin fossils that have turned up since then. This is an example of the self-correcting nature of science, something not seen in the religious belief of those creationists who still tout this example.

Some questions remain. Who, exactly, was responsible for the forgery? Suggestions have included Dawson himself, Sir Arthur Conan Doyle (Dawson’s neighbor), Arthur Keith, and—Steve Gould’s choice—Pierre Teilhard de Chardin, a French Jesuit priest and amateur anthropologist. At least twenty people have been named as possible hoaxers.

A new paper by Isabelle De Groote and many colleagues, just posted at the Royal Society Open Publishing site (reference and free download below), answers other questions, and suggests that the consistency of methods used for both Piltdown I and II specimens, points to a single forger. That forger was almost surely Dawson himself.

De Groote et al. raise three questions (in bold below), and tried to answer them using a combination of morphological analysis, DNA sequencing, radiocarbon dating, and inspection of the fossils. I’ll briefly give their responses below the questions.

  • (Q1)  Lowenstein [16] showed that the mandible was likely to have come from an orang-utan (Pongo sp.). Are the ape jaw, isolated canine (both Piltdown I) and molar (Piltdown II) indeed from an orang-utan? If so, are they likely to originate from the same animal?

Yes, the jaw and teeth from Piltdown I and II came from a single orangutan, as judged by both morphology and mitochondrial DNA sequencing. Carbon dating gave results ranging from 90-500 years, so the jaw and teeth may well have come from an Edwardian skull collection, though the authors couldn’t find records of missing specimens.

The organgutans themselves were likely, given their placement in the DNA phylogeny of known individuals, to have come from southwest Sarawak.

  • (Q2)  How many crania were used to produce the various fragments found at the Piltdown sites and can we assign them to a putative source population?

The authors suggest that at least two modern human skulls, whose dates could not be determined, were used to reconstruct the fossils. No putative source population could be identified, though the authors conjecture that the skulls were from medieval humans.

  • (Q3)  Is there consistency in the modus operandi (MO) used to modify the various materials, linking them to one or more forgers?

The answer to this one is yes. The bones and tooth sockets were all plugged with gravel, originating at both sites, that were mixed with putty. And the same putty was used on the human skulls, as well as to affix the molars back into the organgutan jawbones. That, and the artificial staining that was the same on all specimens, points to a single forger—most likely Dawson, who had the means, opportunity, and anthropological knowledge to create this fake. De Groote et al. summarize their reasons for a single hoaxer:

This is largely because the story originated with [Dawson], he brought the first specimens to Dr Arthur Smith Woodward, Keeper of Geology at the British Museum (Natural History) in 1912, nothing was ever found at the site when Dawson was not there, he is the only known person directly associated with the supposed finds at the second Piltdown site, the exact whereabouts of which he never revealed, and no further significant fossils, mammal or human, were discovered in the localities after his death in 1916.

The final question is this: if it was Dawson, why did he do it? The authors tackle that question, too, and show from letters that Dawson was desperate to be elected a member of the Royal Society. Fortunately, that honor eluded him (it would have been further hay for creationists), but he might well have been elected had he lived longer.

De Groote et al. finish with a lesson: paleoanthropologists shouldn’t hoard or retain exclusive possession of their fossils, for science demands verification through independent observation. I’ll add here the words of Richard Feynman, “For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled.”

h/t: Latha for the original link, also sent by several other readers
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de Groote, I. et al. 2016. New genetic and morphological evidence suggest that a single hoaxer created “Pildown man.”   R. Soc. Open Sci. 2016 3 160328; DOI: 10.1098/rsos.160328. Published 10 August 2016

SCIENCE tells us what Jesus looked like!

December 15, 2015 • 8:45 am

Here’s a headline and subheadline from yesterday’s AOL News.  You can immediately spot two things wrong with it:

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Seriously? That’s a news headline? First of all, it presupposes that a historical Jesus really existed, with the implication that it’s the Jesus who did the stuff described in the Bible. Well, based on the lack of evidence, I’m not prepared to admit that there really was a person who served as a model for Bible Jesus. But a more obvious problem is that any forensic reconstruction of a person’s face demands that we have his or her remains, and of course that’s not the case for Jesus Person. After all, if we had Jesus’s skull, which is what we need to reconstruct the face, we’d have stronger evidence that Jesus really existed.

For example, you probably remember that the remains of King Richard III were found under a car park in Leicester in 2013, identified by DNA analysis, and then his facial features painstakingly reconstructed from the skull (the last link also gives an idea of what Richard sounded like, based on his letters).  Here’s his skull, an early painting, and then the reconstruction based on his remains:

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Reconstruction based on skull:

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Here’s a fascinating video showing how it was done:

Now, what about Jesus? Without a skull, what could they discern what he looked like? Well, they did something dumb, but it’s the best a believer can do. Christianity Today reports excitedly:

With this in mind, the research team acquired three well-preserved skulls from Jerusalem in Israel, where Jesus lived and preached.

Medical artist Richard Neave from The University of Manchester in England then took charge of evaluating the skulls. Using special computer programmes, his team was able to re-create the muscles and skins overlaying the skulls.

The skulls, however, did not provide two key pieces of information about Jesus’ appearance: his hair and his skin colour. To be able to determine these, the researchers analysed drawings found in various archaeological sites in Israel.

The research team ultimately concluded that Jesus had dark eyes, and was bearded following Jewish tradition.

As regards the length of Jesus’ hair, the researchers deviated from the common belief that Christ had long, straight hair. Instead, they assumed that Jesus Christ had short hair with tight curls, based on their analysis of the Holy Bible. [JAC: I don’t think the Holy Bible tells us anything about how Jesus’s hair looked!]

Well that’s certainly convincing, isn’t it? The chance that Jesus, if he really existed, looked like an amalgam of three random skulls dug up in Jerusalem (dates not given), is about nil. Nevertheless, they produced the image given below, which links to the AOL video (click on screenshot:

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What Jesus looked like!!!

Now who does that remind you of? I’ll let readers guess. Not only did they reconstruct the adult Jesus, but they also managed to reconstruct the 12-year-old Jesus, the one who confounded the temple Rabbis and went about his father’s work. To do that, they used the image from the bogus Shroud of Turin and then computer enhanced it. Here he is:

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Adolescent Jesus!!

I am SO convinced! But that’s going to cause a lot of consternation for Christians who were brought up thinking that Jesus looked Aryan, like this:

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I mean, who would ever have thought that Jesus looked like a Jew from Palestine?

I’m not surprised that The Christian Post would claim that this dubious methodology can give us any idea of what Jesus looked like, but what disturbs me is how credible they (and AOL) are about thinking they have any meaningful result. The Christian Post argues that we have actually gained some information from this analysis (my emphasis in following):

For Christians, what Jesus Christ may have looked like has been a mystery. The New Testament of the Holy Bible does not provide any detailed description of Jesus Christ, nor have any drawings of Him been discovered. As a result, Christ has been depicted in various appearances by people from different times and cultures.

Fortunately, science may have found a way for Christians to finally find an answer to the age-old question of how Jesus Christ looks like.

Of course, for them it’s a given that a Jesus-person actually existed, so half the problem is solved right there. Then assume that he was, as the New Testament tells us, a Middle Eastern Jew (of course the Bible gives no description of Jesus), and you’re 3/4 of the way there. The rest is commentary—or rather, credulousness.

h/t: Jonathan S.

Wrongheaded anthropologist claims that humans aren’t apes

November 2, 2015 • 12:30 pm

It’s time to affirm once and for all that humans are apes, and to educate those who say otherwise. To deny that is to deny a palpable fact of biology and evolution: our close ancestry with other primates.

One of those who need education is Jonathan Marks, a cultural anthropologist at the University of North Carolina at Charlotte. The University lists his interests as “Biological Anthropology, Human Genetics, History of Anthropological Thought, Evolution and Human Society.”  And he’s clearly passionate about his field, but his passion sometimes becomes rather aggressive—or even nasty.

I have a report, for instance, that Marks once gave a talk that was, in part, about human genetic variation and “races,” and in it he vehemently denied not only the existence of races, but also attacked studies of genetic variation among human populations, studies that, he claimed, were motivated by racism. When a questioner asked him, “Are you saying that anybody who studies geographic variation in human genes is a racist?”, Marks reportedly answered (in a large seminar), “Yes, and I’d put my boot up their ass.”

He’s now trying to put his boot up another posterior: the notion that humans are apes. But that posterior won’t yield, because, in fact, humans ARE apes. For that is how we’re technically classified in biology. Here’s a simple representation of that, showing that we’re apes; and one could also have put in another bracket around orangs, gorillas, the two chimp species and us, and labeled it “hominids (great apes)”.

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And the classification from Wikipedia:

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Family: Hominidae
Genus: Homo
Species: H. sapiens

If you look up the family Hominidae, you’ll see that it includes all the “great apes”: orangutans, chimps (both common chimps and bonobos), gorillas, and humans. In other words, we are “great apes”. We are also “hominids”, a term once used to refer to every species on “our” side of the evolutionary tree since we diverged from the ancestors of the other apes, but now hominids refers to all the hominidae, and the former “hominid” is now “hominin“.  (You can see the full phylogenetic placement of our species here.) Finally, we are in the more inclusive superfamily Hominoidea, which are all apes, including the great apes and the gibbons.

But Marks disputes this universally accepted classification in a post at the website PopAnth called “Are we apes? No, we are humans.” What he’s doing in the post, as you’ll see below, is denying that we’re apes because the popular conception of apes includes every hominid other than humans, but not humans themselves. He also intimates that there are dire but unspecified political consequences of thinking that we’re apes. Here’s his argument:

Our ancestors were of course apes. That is what science shows. Our closest zoological relatives are apes, and we fall phylogenetically among them–indeed, we are closer to a chimpanzee than that chimpanzee is to an orangutan.

But that elaborates the identities of our ancestors, not us. They were apes, but that doesn’t necessarily tell us what we are. The problem, as Simpson understood decades ago, is that ancestry is not the same as identity.

Yes but the classification of humans as hominids—as apes—does indeed tell us what we are, at least in one sense. It tells us, as you see above, that our closest relatives are other species that share some derived traits (called “synapomorphies”) with other apes, showing that these traits arose after we branched off from other primates. You can see a list of those synapomorphies here.

Marks goes on, confusing the issue of ancestry, which is what our classification with other apes is meant to show, with “identity,” a term that is pretty nebulous and has no formal meaning in biological classification, or even in biology.

We reject the simple equation of ancestry with identity in other contexts. Why should we accept it in science? The short answer is that we shouldn’t.

Science no more says that I am an ape because my ancestors were, than it says that I am a slave because my ancestors were. The statement that you are your ancestors articulates a bio-political fact, not a biological fact. And it is ridiculous and offensive in the modern era, in addition to being false.

Here you can see the ideology creeping in, though I’m not quite sure what ideology Marks projects, though he appears to be a leftist in other contexts. But saying that we’re “apes” has no “bio-political” connotation at all, except in the minds of ideologues like Marks. It doesn’t say that we are our ancestors: it says that we belong to a group whose members share some derived traits and who are evolutionarily diverged from other primates. It becomes clear that Marks is using a concept of “ape” different from that used by other scientists: apes are those other species that we gawk at in cages at the zoo:

What are we? We are human. Apes are hairy, sleep in trees, and fling their poo. I should make it clear: Nobody likes apes more than I do; I support their preservation in the wild and their sensitive treatment in captivity. I also don’t think I’m better than them. I’m smarter than they are, and they are stronger than I am. I’m just not one of them, regardless of my ancestry. I am different from them. And so are you. You and I have 46 chromosomes in our cells; chimpanzees have 48. They are indeed very similar, but if you know what to look for, you can tell their cells apart quite readily.

Then he becomes terminally confused:

. . . Obviously we are very similar to chimps, because we shared a common ancestry with them only a few million years ago. But that doesn’t tell us that we are apes; it only says that we are genetically very similar to apes by virtue of our shared ancestry with them.

And indeed we–that is, Homo sapiens–fall phylogenetically within the group that we call “apes.” Shouldn’t that make us apes?

On the other hand, we also fall phylogenetically within the group that we call “fish.” That is to say, a coelacanth is more closely related to us than it is to a trout. So we fall within the category that encompasses both coelacanths and trout, namely, fish.

Yes, but that’s not the same thing as saying that we fall phylogenetically with the group that we call fish. In fact we don’t (see below).

Yet we are not fish. There are certainly things to be understood by confronting our fish ancestry (such as our gestation in a saline, aqueous environment), but fish can’t read, so if you are reading this, then you are not a fish.

Well, “bony fish”are in the superclass Osteichthyes, to which we don’t belong, but we do belong to the class Sarcoptrygii, which are descendants of early fish, a group that include tetrapods.

Saying that we are not apes is like saying that Drosophila are not flies (dipterans). It’s just dumb, and somehow meant to set us apart from other great apes. Yes, we do have unique traits, but we’re still in the family of hominids. And, contra Marks, that does not mean that we are our ancestors. It means we share a common ancestor that lived in the past.

Historically, Marks is a bit like Deepak Chopra, who can’t let a criticism slide. So when the commenters try to set him straight, he goes into the comments section and argues with them—nearly always a mistake, particularly if there are biologists afoot. Here’s a humorous exchange from that section:

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Finally, it may not be irrelevant that Marks is also author of a book called Why I am not a Scientist, characterized like this:

Science, Marks argues, is widely accepted to be three things: a method of understanding and a means of establishing facts about the universe, the facts themselves, and a voice of authority or a locus of cultural power. This triple identity creates conflicting roles and tensions within the field of science and leads to its record of instructive successes and failures.

Well, whatever this postmodern babble means, if Marks wants to establish that he’s not a scientist, he’s gone quite a ways towards that goal in this piece.

And let’s not forget that denying that humans are apes plays right into the hands of religious human exceptionalism as well as creationism. It may not be surprising that Marks’s University web page says this: “Prof. Marks is on leave during the Academic Year 2013-2014, participating as a Templeton Fellow at the Institute for Advanced Study at the University of Notre Dame.”