Thursday, May 25, 2017

3.3 Million Year Old Vertebral Column Confirms Human Pattern of Au. afarensis

The science site PhysOrg has posted a story on a study of the 3.3 million year old fossil from the site of Dikika, in the Afar Triangle.  The fossil, known as Selam, is an almost complete skeleton of a 2 ½ year-old child. From the story:
Many features of the human spinal column and rib cage are shared among primates. But the human spine also reflects our distinctive mode of walking upright on two feet. For instance, humans have fewer rib-bearing vertebrae - bones of the back - than those of our closest primate relatives. Humans also have more vertebrae in the lower back, which allows us to walk effectively. When and how this pattern evolved has been unknown until now because complete sets of vertebrae are rarely preserved in the fossil record.

"For many years we have known of fragmentary remains of early fossil species that suggest that the shift from rib-bearing, or thoracic, vertebrae to lumbar, or lower back, vertebrae was positioned higher in the spinal column than in living humans. But we have not been able to determine how many vertebrae our early ancestors had," said Carol Ward, a Curator's Distinguished Professor of Pathology and Anatomical Sciences in the University of Missouri School of Medicine, and lead author on the study. "Selam has provided us the first glimpse into how our early ancestors' spines were organized."
This gives us much better evidence of how bipedality was practiced in some of the earliest hominins. We know, from the footprints at Laetoli and the hip remains of Lucy, that Au. afarensis was bipedal but now we know that the rib structure had evolved into a more human pattern. 

Wednesday, May 24, 2017

Ken Ham Needs to Stay Away From Twitter

Like Donald Trump, Ken Ham sometimes shoots off at the mouth on his Twitter feed.  Hermant Mehta, of Patheos records his latest post:

As with most of the things that Ken Ham says about evolution, it reflects absolutely no knowledge of the subject and includes invective and nonsense.  As Mehta points out:
The entire point of science is to take what we know, try something new, find out new information, and expand our base of knowledge. The evidence for evolution springs from that process. You don’t need to regurgitate it. You don’t need to point to a science textbook. You can test it for yourself.
This is something Ken Ham will never understand.

P.S. This is one of the reasons I don't use Twitter.


Was the LCA in Europe????

Was the last common ancestor of apes and humans in Europe?  That seems to be the gist of a study published in the PLoS One.  Nicole Mortillaro, of CBC News reports:
A jawbone discovered by German troops in Athens during the Second World War could be evidence that apes and humans diverged 200,000 years earlier than the current theory says.

Chimpanzees and bonobos are the nearest known relatives to humans, sharing 99 per cent of our DNA. It's believed that we split between five and seven million years ago.

However, researchers analyzing two fossils — a jawbone from a German museum and an upper premolar from a collection in Bulgaria — concluded their ages to be roughly 7.2 million years, and belonging to a pre-human.
From the paper in PLoS:
The split of our own clade from the Panini is undocumented in the fossil record. To fill this gap we investigated the dentognathic morphology of Graecopithecus freybergi from Pyrgos Vassilissis (Greece) and cf. Graecopithecus sp. from Azmaka (Bulgaria), using new μCT and 3D reconstructions of the two known specimens. Pyrgos Vassilissis and Azmaka are currently dated to the early Messinian at 7.175 Ma and 7.24 Ma. Mainly based on its external preservation and the previously vague dating, Graecopithecus is often referred to as nomen dubium. The examination of its previously unknown dental root and pulp canal morphology confirms the taxonomic distinction from the significantly older northern Greek hominine Ouranopithecus. Furthermore, it shows features that point to a possible phylogenetic affinity with hominins. G. freybergi uniquely shares p4 partial root fusion and a possible canine root reduction with this tribe and therefore, provides intriguing evidence of what could be the oldest known hominin.
Hominin, in this case, means humans and their premodern forms.  I think it is more than somewhat suspect to base a far-reaching hypothesis on one trait, even if it is the p4 root. It is commonly held that the last common ancestor of apes and humans was in Africa, sometime around 7.5 to 8 million years ago, but we have no fossil evidence to support that position.  While it is certainly true that the further back in time you go, the more ape-like our ancestors get, there is simply no smoking gun.

The world will not end if the LCA is, in fact, in southern Europe, but if it is, then it raises some interesting questions.  For one, if the LCA is in Europe, why are all of its hominin descendants in Africa?  So far, even discounting Sahelanthropus, which is a surface find and was crushed, all of the late Miocene and early Pliocene hominin remains are found in either the Afar triangle (Ardipithecus) or the Tugen Hills, in Kenya (Orrorin tugenensis).  If you add Sahelanthropus, then Chad comes into the picture. Additionally, why have we found no post-split hominids in southern Europe?  So far, all that has come out of the ground in this region is middle to late Miocene apes.

Other hurdles exist to acceptance of this idea.  For one, it is pretty clear that our closest living relatives, genetically, are the chimpanzees, who reside in the tropics of central Africa.   Next on the list is the gorilla, also found in the tropics of Africa.  Why have we found no precursors to these hominoids in southern Europe? 

On the other hand, the fossil find has been securely dated to the Messinian Event, in which the Mediterranean Sea effectively dried up, suggesting the possibility that the ancestors of the Pliocene hominins from North Africa migrated from southern Greece.  If this is so, then it raises the dark and ominous thought that much of the information regarding the LCA lies at the bottom of the Mediterranean Sea. That is terrible to contemplate.  This would also mean that Chimpanzees and Gorillas are the survivors of a group of Miocene apes that ranged from southern Europe to central Africa.  We know that the ancestors of chimpanzees once upon a time occupied the East African Rift Valley, but are now restricted to central and west Africa.   If their original range extended up into Egypt and beyond, then perhaps we are looking at a similar situation for their ancestors, as well.  

A whole lot more investigation needs to be done and more fossil remains need to be found to shore up the European LCA hypothesis.  Given that this new information does not come from newly discovered fossils does not raise my hopes. 

Tuesday, May 23, 2017

Gallup: Belief in Creationism At All-Time Low

Color me skeptical, but the Gallup organization has released its latest poll on the acceptance of creationism and the numbers are down.  Art Swift writes:
The percentage of U.S. adults who believe that God created humans in their present form at some time within the last 10,000 years or so -- the strict creationist view -- has reached a new low. Thirty-eight percent of U.S. adults now accept creationism, while 57% believe in some form of evolution -- either God-guided or not -- saying man developed over millions of years from less advanced forms of life.

This is the first time since 1982 -- when Gallup began asking this question using this wording -- that belief in God's direct creation of man has not been the outright most-common response. Overall, roughly three-quarters of Americans believe God was involved in man's creation -- whether that be the creationist view based on the Bible or the view that God guided the evolutionary process, outlined by scientist Charles Darwin and others. Since 1982, agreement with the "secular" viewpoint, meaning humans evolved from lower life forms without any divine intervention, has doubled.
As the pollsters suggest, this may reflect a growing secularization in American society and not necessarily a change in the way that people understand evolution.  As with most of these polls, however, education plays a role:
Higher education levels are associated with less support for creationism and higher levels of belief in the evolutionary explanation for human origins. Belief in creationism is 21% among those with postgraduate education versus 48% of those with no more than a high school diploma. Agreement with evolution without God's involvement is 31% among postgrads versus 12% among Americans with a high school education or less.

However, even among adults with a college degree or postgraduate education, more believe God had a role in evolution than say evolution occurred without God.
This is not surprising considering that most left-leaning colleges and universities do their level best to beat belief in God out of the students.I came along at a time before the advent of oppressive political correctness and identity politics, so it was okay to believe in God and still be educated. 

What is always interesting to me is the “religious preference” part of the chart. Catholics consistently accept God-driven evolution at a higher percentage than protestants. As with previous polls, at least 50% of protestants believe the young earth creation position, although that number appears to be dropping just a bit.  It is encouraging that 45% of those with post-graduate degrees think that evolution occurred but that it was a God-directed process.  Here's to hoping that number increases.

Monday, May 22, 2017

Bryan College Gives Ken Ham Honorary Doctorate in Science

In what one of my friends calls “perhaps the most perfectly ironic thing to have ever happened,” Bryan College has bestowed upon Ken Ham an honorary doctorate in science for its graduate exercise on May 8. Aside from the fact that Ham has very little background in hard science, this is clearly a move by the president and board of directors to align the college with the hard-line young earth position that Ham espouses and is a slap in the face to those who have struggled to create an open atmosphere of learning at the college.

Joel Edmund Anderson, author of The Heresy of Ham, is not amused:
I’m sure Ken Ham views this as a minor victory in his battle against secular humanism, for just the day before, on May 7, 2017, he wrote a short blog post that discussed how the Department of Defense has just recently added “humanism” on its list of religions. The entire article can be summed up in this short paragraph:

“Humanists are very inconsistent when it comes to their religious designation. They want the privileges that come with a religious designation (such as chaplains), but they don’t want the public perceiving them as religious because many humanist groups spend millions of dollars suing public school districts or counties to get rid of religion (mostly just Christianity). And what do they want taught in place of Christianity or a Christian worldview? Humanism! They are aggressively pushing to have their secular humanist religion imposed on generations of children —and they are using our taxpayer dollars to do this.”

Yes, secular humanism is a religion, and our children are being indoctrinated into the secular humanist religion in our schools. As Ham concludes his article by quoting Ephesians 6:12-13 and stating: “This struggle over worldviews just shows that we are engaged in a spiritual battle.”

This is the kind of work that gets Ham an honorary doctorate…in science…from Bryan College.
If you have a very limited understanding of science in the first place, then, yes, this would be acceptable. As Anderson points out, Ham's position betrays a complete inability to differentiate between philosophical naturalism and methodological naturalism (that is not the only problem Ham has with science, but it is a big one).  He quotes the late evolutionary biologist William Provine, famous for his treatise that there is no God, no moral absolutes and no afterlife and, further, that evolutionary theory supports this.  To this, he points out:
This is the fundamental, contradictory problem with philosophical naturalism: it’s claim that the natural world is all that exists is not a scientific claim. So, when Provine and Dawkins claim that evolution teaches us that there is no God, and that there is no purpose or meaning in life, they are wrong, and they are playing a philosophical trick on you. Evolution describes natural processes; evolution does not state nature is all that exists. Science and evolution do not support that philosophical claim, period.
Unfortunately, Ken Ham, and, increasingly, other young earth creationists are taking this position, ironically, in support of atheists like Sam Harris and Richard Dawkins. Make no mistake, it is a philosophical position.  One of the things I am quite clear about with my children when they ask me about evolutionary theory is that it is not capable of testing hypotheses involving the origin of life.  It needs life to work.

One of the drawbacks of using the Classical Conversations curriculum is their reliance on a truly terrible book called It Couldn't Just Happen. The author, Lawrence Richards, has adopted this misunderstanding between philosophical and methdological naturalism.  Consequently, all of his excursions into evolutionary theory are predisposed against it, because it is, by definition, atheistic.  This is unfortunate. 

I do not believe that Bryan College will prosper as a result of this move.

Sunday, May 21, 2017

Off-Topic: The Troubling State of Social Science

Skeptic Magazine is reporting on a hilarious (in some ways) hoax that was perpetrated on the world of gender studies.  Two authors, Peter Boghossian, a professor of philosophy and James A. Lindsay, a Ph.D. in math and physics,  submitted a paper that, by their own admission, made absolutely no sense but appealed to far-left, liberal socio-political perspectives.  They write:
Assuming the pen names “Jamie Lindsay” and “Peter Boyle,” and writing for the fictitious “Southeast Independent Social Research Group,” we wrote an absurd paper loosely composed in the style of post-structuralist discursive gender theory. The paper was ridiculous by intention, essentially arguing that penises shouldn’t be thought of as male genital organs but as damaging social constructions. We made no attempt to find out what “post-structuralist discursive gender theory” actually means. We assumed that if we were merely clear in our moral implications that maleness is intrinsically bad and that the penis is somehow at the root of it, we could get the paper published in a respectable journal.
In other words, as long as it bashed men, it was okay, even if the premise of the paper was completely unsupportable. As the authors note, it gets worse:
Not only is the text ridiculous, so are the references. Most of our references are quotations from papers and figures in the field that barely make sense in the context of the text. Others were obtained by searching keywords and grabbing papers that sounded plausibly connected to words we cited. We read exactly zero of the sources we cited, by intention, as part of the hoax. And it gets still worse…

Some references cite the Postmodern Generator, a website coded in the 1990s by Andrew Bulhak featuring an algorithm, based on NYU physicist Alan Sokal’s method of hoaxing a cultural studies journal called Social Text, that returns a different fake postmodern “paper” every time the page is reloaded. We cited and quoted from the Postmodern Generator liberally; this includes nonsense quotations incorporated in the body of the paper and citing five different “papers” generated in the course of a few minutes.
On one level, this is hilarious.  It was difficult to get through either the paper, itself, or the authors' report of the hoax.  At one point, I was laughing so hard, tears were coming out of my eyes.  On another, it is deeply concerning.  The editors of this journal should resign in disgrace.

The social sciences have always had a somewhat checkered reputation in the general world of science, and examples like this simply reinforce this perspective. Once upon a time, I had an opportunity to read a social sciences dissertation written by someone that I knew at the University of Tennessee.  He made it clear that the dissertation had already been accepted by the graduate school.  It was terrible, full of spelling, grammatical and logical errors.  I marveled that, had I turned in the same kind of work to my advisor, he would have thrown it back in my face.

It is clear that, long ago, the social sciences burned objective scientific principles at the altar of progressive, ideologically hidebound politics.  This was exposed by the original hoax perpetrated by Alan Sokal, in 1996, in the journal Social Text.

What has just transpired in the journal Cogent Social Sciences, is unacceptable and all of those involved should hang their heads in shame.  Unfortunately, as the authors point out:
As a matter of deeper concern, there is unfortunately some reason to believe that our hoax will not break the relevant spell. First, Alan Sokal’s hoax, now more than 20 years old, did not prevent the continuation of bizarre postmodernist “scholarship.” In particular, it did not lead to a general tightening of standards that would have blocked our own hoax. Second, people rarely give up on their moral attachments and ideological commitments just because they’re shown to be out of alignment with reality.
Most people do not see themselves in the same light that other people do, and the facile nature of the discipline of "gender studies" will likely continue, in spite of this hoax. Nonetheless, these two authors have done an amazingly important service in exposing the shoddy nature of the academic standards of it.
P.S. for those of you in need of a laugh, here is the Postmodern Generator.  One of the papers it generated was from Barbara Porter, Professor of English at the University of Southern North Dakota at Hoople. 

Wednesday, May 17, 2017

Matt Young Not Happy With Treatment of Andrew Snelling

Neither am I.  It seems that Andrew Snelling, a young earth creationist, wanted to do a geological study of rocks in the Grand Canyon and so petitioned the National Park Service to remove a few rocks to do this.  After reviewing the proposal that Snelling sent, the Park Service declined.  Citing religious descrimination, Snelling is suing the Park Service.  Here is an excerpt from the story in the Phoenix New Times:
In the federal complaint filed on Tuesday, ADF uses several key e-mails by scientists who put their feelings in writing to demonstrate the bias Snelling says he encountered.

"It is difficult to review such an outlandish proposal," Ron Blakely of Northern Arizona University told NPS officials in 2014, when he was asked for his opinion about Snelling's proposal.

Gary McCaleb, ADF senior counsel, told Phoenix New Times that Snelling "has been stonewalled for three years. Something's fundamentally wrong when a government stops a good scientist from doing good research."

Whether it's actually "good" research is debatable, of course. But it's unclear why government officials care what Snelling concludes about a relatively small collection of Grand Canyon rocks.
Here is Matt Young's take on it, from Panda's Thumb:
I do not know how many people request permission to remove a few rocks from the Grand Canyon. But Dr. Snelling’s proposal was to remove no more than 60, ~0.2 kg samples to use in his research. He did not ask for any funding. There is not the slightest doubt that his research would conclude that the Grand Canyon was something like 6000 years old. That is, he is pursuing, in the jargon of the times, fake research. So what? It would have been better if the National Park had allowed him to have his rocks and go play in his sandbox.

Instead, Dr. Snelling is now being represented by the Alliance Defending Freedom, which has just posted an article Grand Canyon National Park continues history of hostility toward religion, and may become something of a cause célèbre among the right wing. The complaint, incidentally, refers irrelevantly to Donald Trump’s recent Executive Order on “religious freedom.”
This kind of thing gives ammunition to the young earth creationists and it was completely unavoidable. The story in Phoenix New Times suggests that reviewer Karl Karlstrom criticized Snelling's beliefs in a letter he sent to the Park Service in 2014.  Without that letter, it is hard to evaluate that charge.  It may be simply that he thought that Snelling's interpretation of the scriptures had no empirical support (which it doesn't).  That is not the same as criticizing his religious beliefs.  On the other hand, if he did criticize Snelling's beliefs, it will be much easier to get a charge of religious bias to stick.  

Friday, May 12, 2017

New Post on Homo naledi From Darrel Falk and Deb Haarsma

Darrel Falk and Deb Haarsma have teamed up on a new post about the peculiar South African hominin, Homo naledi, a find on which I reported a few days back.  Darrel Falk:
This is a wonderful time to be studying human origins. Scholars used to think that there was a slow steady progression of one single species after another becoming more and more human-like through time. That’s not the way it was at all. Although these fossils give no evidence for when H. naledi went extinct, it’s clear it was our contemporary in Africa for at least a little while. There also were at least several other hominin species outside of Africa at that same time. Some members of our species migrated out of Africa to Eurasia about 70,000 years ago, only to find that Homo neanderthalensis and the related, but distinctive Denisovans were already there. At the same time, the primitive diminutive species, H. florisiensis, occupied an island in Indonesia, and H. erectus was in eastern Asia. Meanwhile, back in Africa, we know from genetic evidence that, in addition to H. naledi, another unknown hominin species was present and interbred with our species as recently as 30,000 years ago. So our lineage shared life on this planet with a whole set of other species up until just a few thousand generations ago.
A bit back, I wrote a BioLogos post where I examined the hominin diversity in the early to middle Pleistocene, in which I asked the question How Many Forms Were There?  In that post, I pointed out that our simplistic notions of hominin taxonomy needed to be seriously re-evaluated. Where we once upon a time thought that there was only one species of hominin between 3 and 3.5 million years ago, there may, in fact, have been anywhere from three to five.  It is becoming more likely that this is a pattern that characterizes human evolution, perhaps, all the way up to the ascendancy of modern humans.  If this is so, then Bernard Wood is correct, in that we have many, many more species throughout the range of human evolution than we thought.  This discovery will cause a radical rethink of how we interpret species in the human fossil record.  Witness the rise of systematics.

Wednesday, May 10, 2017

Australopithecus sediba Voted Off the Island

This does not surprise me.  Science Magazine has a short story which suggests strongly that the characteristics in Au. sediba render it unsuitable for a possible ancestor to the genus Homo
With its fossils dated to 1.98 million years ago, Au. sediba is too young to be directly ancestral to all members of the genus Homo. But Berger and his colleagues proposed in 2010, and again in 2013 in six papers in Science, that given the many humanlike traits in Au. sediba’s face, teeth, and body, the Malapa fossils were a better candidate than Lucy or other East African fossils to be ancestral to Homo erectus, a direct human ancestor that appeared 1.8 million years ago.

In a talk here, though, paleoanthropologist Bill Kimbel of Arizona State University in Tempe analyzed the most complete skull of Au. sediba and systematically shot down the features claimed to link it to early Homo. Kimbel noted that the skull was that of a juvenile—a “7th grader”—whose face and skull were still developing. In his analysis, with paleoanthropologist Yoel Rak of Tel Aviv University in Israel, he concluded that the child already showed traits that linked it most closely to the South African australopithecine Au. africanus, a species that lived in South Africa 3 million to 2.3 million years ago. And had it survived to adulthood, its humanlike facial traits would have changed to become even more like those of Au. africanus.

For example, the breadth of the young Au. sediba’s cheekbones appears narrow, as in early Homo. But by studying other australopithecine, ape, and Homo fossils to see how features of the cheekbones change as individuals grow and chewing muscles develop, Kimbel and Rak could predict how the boy’s face and skull would have looked if he’d grown up to be an adult. The resemblance to Au. africanus is so striking, in fact, that Kimbel thinks Au. sediba is a closely related “sister species” of Au. africanus—and not a long-lost human relative. “We don’t believe … that Au. sediba has a unique relationship to the genus Homo,” says Kimbel.
At this point, it is pretty hard to tell where a precursor might be found. We know that there was considerable variability in australopithecines throughout the Plio-Pleistocene but, as of yet, no good candidate has arisen.What seems to be clear, however, is that there is a general trend toward more modern morphology in the pelvis and hands, as exhibited by Au. sediba.  Whether or not these characteristics are present in other specimens of Au. sediba is, however, unknown.  As Kimbel notes, we need an adult one to see for sure. 

Tuesday, May 09, 2017

A Conversation with Scot McKnight

Scot McKnight, a New Testament professor at Northern Seminary in Lombard, Illinois, and co-author of Adam and the Genome, with Dennis Venema, recently was interviewed and said that it was a BioLogos conference and the evidence he was told there that changed how he viewed the first three chapters of Genesis.  Baptist News Global has the scoop:
“The number one reason young people walk away from the faith is the conflict of their interpretation of Scripture with their interpretation of science,” he said. “Let it be emphasized that we are dealing here with the interpretation of Scripture, not necessarily Scripture’s truest meaning. And, yes, we are dealing with a theoretical construct called evolution.” McKnight said many people on both sides regard science and faith as “implacable enemies.”

“Some scientists think we are fools for believing in the Bible and therefore in Jesus,” he said, “while for some conservative theologians and pastors and bloggers, scientists are materialists, atheists, and those who think they are Christian and evolutionist are oblivious to the slippery slide they are halfway down.”

McKnight said the question he hears most often when discussing Gen. 1-3 is “do you believe in a historical Adam?” It’s a question “loaded with theological meaning,” he said, including belief that Adam and Eve were real people who had a “biological and procreative relationship with every human being who has ever lived” and that all people living today possess a share of their DNA.
I am about three-quarters of the way through the book and it is worth the read. He is one of a growing chorus of people (notably John Walton also) who are raising the concern that people are walking away from the faith because they get to college and encounter grounded science that conflicts with the non-grounded creationism they were taught in high school or home school.

It is clear that McKnight has read Walton, however.  Here is how he puts it:
McKnight said he doesn’t like the terms “myth,” “fable” and “legend” when applied to Genesis, so he uses “theological narrative.”

“I read the text as a theological narrative about God as creator, about humans assigned by God to a vocation in God’s cosmic temple on God’s sacred time, and I see the tragedy of humans who refuse to do what God said,” he said.
This perspective is absorbed from Walton's The Lost World of Genesis One, another book I am piecing through, which is considerably denser than Adam and the Genome but worthwhile, nonetheless. 

Surprising New Information About Homo naledi

The Atlantic (and other outlets) has a story on new information on the date of the Homo naledi fossils from Rising Star Cave and it is...surprising.  As Sarah Zhang writes:
The one thing everyone agrees is that the fossils themselves are spectacular. In 2015, researchers unveiled 1,500 hominin fossils found deep in a South African cave, excavated by six cavers who were all skinny, short, and female. The hominin, a new species the team christened Homo naledi, was an unusual mix of the old and modern. Their heads were small, suggesting an early hominin perhaps more than a million years old. But their feet were stiff for walking upright and their hands adept like modern humans.

So in the media frenzy that followed—a National Geographic cover, a documentary, numerous articles—the question kept coming up: How old are these Homo naledi fossils, really? What do they tell us, if anything, about the origin of Homo sapiens?

To that first question, the researchers now have an answer: 236,000 to 335,000 years old. As for the second question, well, it’s complicated. “You can’t tell simple stories anymore,” says Lee Berger, a paleoanthropologist at the University of the Witwatersrand who led the research. “This is the gigantic message out of Homo naledi.” The age of these fossils puts these strange, small-brained yet human-like hominins in South Africa just before the emergence of the first anatomically modern Homo sapiens.
Holy Liang Bua, Batman!  If the bones really are 236k, then that would put them roughly 40-50 k years before the advent of modernity represented by the Omo 1 cranium.  Admittedly, that skull is fragments “swimming in plaster” but we have a pretty good idea of what it looks like. We certainly have modernity in the Bouri remains from Herto at 160 ky.

How do we know how old the fossil are?  From the eLife article:
Now, Dirks et al. – who include many of the researchers who were involved in the discovery of H. naledi – report that the fossils are most likely between 236,000 and 335,000 years old. These dates are based on measuring the concentration of radioactive elements, and the damage caused by these elements (which accumulates over time), in three fossilized teeth, plus surrounding rock and sediments from the cave chamber. Importantly, the most crucial tests were carried out at independent laboratories around the world, and the scientists conducted the tests without knowing the results of the other laboratories. Dirks et al. took these extra steps to make sure that the results obtained were reproducible and unbiased.
More specifically, they did Electron Spin Resonance (or Electron Paramagnetic Resonance), Uranium-Thorium disequilibrium, Optically Stimulated Resonance and radiocarbon dating.  This is probably not the last word on the dating of the fossils and there are quite a few assumptions that have been made regarding the provenance of the fossils to the cave sediments, but this is the closest thing that we currently have. One of the critical problems in dating much of the South African cave deposits is their relationship to the hominins found there.  Often, the caves opened up at the top and the fossil remains either fell in, were dropped in or they crawled in.  What makes the Rising Star remains so peculiar is that this cave did not form in the traditional way and the bones were so far into the cave. 

Where does this leave us? It leaves us with more questions than answers.  It has been common consensus that, while there was considerable variability in hominin morphology throughout the Pliocene and early to middle Pleistocene, that this "settled down" and that variability diminished as we made the transition to modern humans.  These fossils suggest the opposite: that large amounts of variability were, in fact, present throughout the range of human existence and only recently (200ky to the present) did this variability drop off.

I am quite sure that more studies will be done to elucidate the relationship that these fossils (there are more very similar fossils next door in the Lesedi cave complex) have to other forms in Africa.  There are obviously very peculiar cultural interactions going on, though (or lack, thereof).  With the Liang Bua remains in East Asia, hypotheses of endemic dwarfism and isolation have been put forth to explain why these remains are so diminutive and primitive.  It is more difficult to put forth these same arguments here where there are few to no barriers to migration and interaction between groups. 

Monday, May 08, 2017


This is a follow-up post to another one on March 21.  Hot on the heels of the Texas State Board of Education striking language in the state science standards that would require teachers to “evaluate” scientific theories as they teach them, comes another bill that is an attempt to allow teachers to do exactly that. The Texas Observer has this to say:
Representative Valoree Swanson, R-Spring [natch!], is making a case for why her bill protecting the “academic freedom” of public school teachers wouldn’t amount to an unconstitutional teaching of religion in classrooms.

House Bill 1485 would “free our teachers to where they don’t live in fear of frivolous accusations” and give teachers the ability to criticize scientific theories, she told members of the House Public Education Committee Tuesday evening. Among the theories that teachers would be able to question in elementary, middle school and high school classrooms? Climate change.
Of course she doesn't stop at climate change:
But under Swanson’s bill, public schools are encouraged to create an environment where students can consider “differences of opinion about scientific subjects” and “assist” teachers in teaching subjects that may cause controversy. The bill lists climate change, biological evolution, the chemical origins of life and human cloning as examples of such controversial subjects.

The bill also prohibits school administrators and the State Board of Education from blocking teachers who are helping students “understand, analyze, critique and review” the “scientific strengths and weaknesses” of science subjects.
How is that climate change, biological evolution, the chemical origins of life and human cloning are always the “examples?”  How do you create this kind of environment with “differences of opinion about scientific subjects” without evaluating them?   My experience is that most high school teachers are not equipped to evaluate these subjects because they do not work in these fields.  That is why the language to do so was stripped from the original wording.  The study of the biochemical origins of life is extremely technical, with a  considerable amount of mathematics and, as with all of these subjects, requires considerable time and education to master. 

Nothing good can come from this.