More Evidence For Bipedality at 4.5 MYA

Out of Case Western Reserve comes a study of some new fossil material that sheds like on early human bipedal adaptation.  From ScienceDaily:

Scott W. Simpson, PhD, led an analysis of a 4.5 million-year-old fragmentary female skeleton of the human ancestor Ardipithecus ramidus that was discovered in the Gona Project study area in the Afar Regional State of Ethiopia.

The newly analyzed fossils document a greater, but far from perfect, adaptation to bipedalism in the Ar. ramidus ankle and hallux (big toe) than previously recognized. "Our research shows that while Ardipithecus was a lousy biped, she was somewhat better than we thought before," said Simpson.

While the weight of evidence has always a bit more than slightly favored the facultative bipedality of Ardipithecus ramidus, this research provides greater support for this hypothesis.  In my class, I stress the difference between facultative bipedality (practiced by Ardipithecus) and obligate bipedality (practiced by every other hominin).  Additionally, from the article¹:

The more complete adoption of bipedality in the australopiths resulted in the loss of functionally critical adaptations to arboreality present in Ardipithecus such as a grasping, opposable hallux, an antero-posteriorly broad pelvis with reorganization of the origin (and most likely function) of the hamstring muscles, and a more derived humero-femoral ratio. The changes in the size and structure of the dentition in the subsequent australopiths (larger molar and premolar crowns, increased enamel thickness, more robust mandibles) indicates a major behavioral and dietary shift for most hominins (perhaps excluding the species indicated by the Burtele foot) that occurred about 4.2 Ma with the earliest appearance of Australopithecus (Leakey et al., 1995, White et al., 2006).

Many of these changes, then, appear to have occurred somewhat rapidly, once the early hominins moved away from the forest and into the fringe.  Once we thought that bipedality originated in the forest/fringe.  The Ardipithecus data have killed this hypothesis. 


¹Scott W. Simpson, Naomi E. Levin, Jay Quade, Michael J. Rogers, Sileshi Semaw. Ardipithecus ramidus postcrania from the Gona Project area, Afar Regional State, Ethiopia. Journal of Human Evolution, 2019; 129: 1 DOI: 10.1016/j.jhevol.2018.12.005

The Brain of Little Foot

Science Daily had a story just a bit back about research done on the new information surrounding the Little Foot australopithecine remains from South Africa.  They write:

MicroCT scans of the Australopithecus fossil known as Little Foot shows that the brain of this ancient human relative was small and shows features that are similar to our own brain and others that are closer to our ancestor shared with living chimpanzees.

While the brain features structures similar to modern humans -- such as an asymmetrical structure and pattern of middle meningeal vessels -- some of its critical areas such as an expanded visual cortex and reduced parietal association cortex points to a condition that is distinct from us.

One of the things that comes out in the paper is how much reorganization of the cranium we share with the higher primates, suggesting that quite a bit of brain evolution occurred prior to the Last common ancestor. The paper is currently free (at least I had no trouble accessing it) at http://dx.doi.org/10.1016/j.jhevol.2018.11.009. If not, the abstract is.

New Chinese Material Pushes the Exit From Africa to 2.1 mya

Nature is reporting research on new Chinese material that strongly suggests that the Georgian site of Dmanisi is not the earliest location to which migration out of Africa went.  Here is the abstract:

Considerable attention has been paid to dating the earliest appearance of hominins outside Africa. The earliest skeletal and artefactual evidence for the genus Homo in Asia currently comes from Dmanisi, Georgia, and is dated to approximately 1.77–1.85 million years ago (Ma)1. Two incisors that may belong to Homo erectus come from Yuanmou, south China, and are dated to 1.7 Ma2; the next-oldest evidence is an H. erectus cranium from Lantian (Gongwangling)—which has recently been dated to 1.63 Ma3—and the earliest hominin fossils from the Sangiran dome in Java, which are dated to about 1.5–1.6 Ma4. Artefacts from Majuangou III5 and Shangshazui6 in the Nihewan basin, north China, have also been dated to 1.6–1.7 Ma. Here we report an Early Pleistocene and largely continuous artefact sequence from Shangchen, which is a newly discovered Palaeolithic locality of the southern Chinese Loess Plateau, near Gongwangling in Lantian county. The site contains 17 artefact layers that extend from palaeosol S15—dated to approximately 1.26 Ma—to loess L28, which we date to about 2.12 Ma. This discovery implies that hominins left Africa earlier than indicated by the evidence from Dmanisi.

For the new site sequence data, we don't have any hominin remains so we don't know exactly what these folks looked like but the tools are very primitive.  A section from a companion piece reads thus:

The identity of their makers is, for now, unclear: no hominin bones have been recovered at Shangchen. “We would all love to find a hominin — preferably one with a tool in its hand,” says Dennell. Homo erectus is one possibility, because some of the earliest members of this species were found at Dmanisi. But Dennell thinks that the Shangchen toolmakers belonged to an earlier species in the genus Homo.

Petraglia and Rezek both say that the age of the tools — not to mention the possibility that hominins arrived in China even earlier than the 2.12-million-year mark — suggests that the toolmaker was a species such as Homo habilis. This relatively small-brained hominin is thought to have been confined to Africa between around 2.4 million to 1.4 million years ago.

Jungers holds open the possibility that the Shangchen toolmaker was a species of Australopithecus, a group of more ape-like hominins to which the iconic fossil Lucy belongs. So far, all Australopithecus fossils have been discovered in Africa.

Before his death, Grover Krantz argued for the presence of Australopithecus in East Asia but could never get anyone to come on board with him. Everyone was pretty content to label what was coming out of the ground as Homo erectus.I think it would be a stretch if the hominins from Shangchen were australopithecines since we don't see any advanced species of Australopithecus in East or North Africa between 2 and 2.5 mya.  In fact, Au. boisei drops out around 2.1, likely out-competed by early Homo.

Nonetheless, something was making stone tools in China at 2.1 mya and that is “Yuuuuge” news. 

How Intelligent Was Homo naledi?

Discover Magazine (and other outlets) are running a story which questions how important cranial size is to overall intelligence.  The focus of this inquiry is Homo naledi, the small-brained hominin that is now thought to be no more than 200ky old.  Lee Berger, who was on the team that discovered Homo naledi has always argued that, because of the comparative difficulty of navigating the cave, that she was placed in the Rising Star Chamber intentionally.  At issue is the brain size:

When it comes to brain volume, previous research established that Homo naledi‘s was 465-560 milliliters. (In today’s study, the authors acknowledge those earlier numbers, based on virtual reconstructions, but also perform their own physical reconstructions and measure the volume with a water displacement method, arriving at a similar range of 460-555 mL.)

This is very small. As the authors note, contemporary hominins possessed brains well over 1000 cc at this point. It was the complexity of H. naledi's brain that surprised people:

Homo naledi‘s inferior frontal and lateral orbital gyri were organized notably more like that of other members of the genus Homo than that of australopiths. These are parts of the brain associated with complex behaviors, such as communication, planning and tool-making, that are particularly important in our lineage.

Finding Homo naledi‘s brain was structurally similar to that of larger-brained members of the genus tells us two important things. First, it means Homo naledi itself was likely capable of more complex behavior than australopiths with a similar brain volume but different brain structure. Second, it torpedoes the old notion that Homo brains grew steadily in size and complexity until reaching the evolutionary pinnacle that is Homo sapiens (/sarcasm, just a touch).

As we discover that early Homo was behaviorally more complex than we thought, it also forces us to rethink what went on later in hominin evolution and re-evaluate evidence of complexity in H. erectus and archaic H. sapiens. 
 

Q&A With Lee Berger on Human Evolution

The Sunday Times has an interview with Lee Berger about human evolution, in advance of his new book, co-written with John Hawks, Almost Human: The Astonishing Tale of Homo naledi and the Discovery That Changed Our Human Story. As was reported earlier, the original fossils were undated but appeared to be reflective of an early stage in the development of Homo. This idea was shattered when new dates were derived.  As I wrote at the time:

Homo naledi, however, was missing a date—until recently. Nearly everyone in the scientific community thought that the date of the Homo naledi fossils, when calculated, would fall within the same general time period as other primitive early Homo remains. We were wrong. The radiometric dates—recorded using several methods carried out at different laboratories—yielded almost identical ages of between 236 and 300 thousand years before the present (BP). This was an order of magnitude younger than we expected. To say we were surprised would be an understatement.

Interestingly, the interviewer asks no important questions about Homo naledi or the Dinaledi Star cave, itself.  Amid all of the sturm und drang of his tortuous relationships with Ron Clarke and Philip Tobias (✟ 2012), there is one interesting question about human evolution in general:

Throughout the final chapters of the book you often mention how much there still is to learn about Homo naledi and that it’s very likely that there are more early hominim species which are yet to be discovered. The skeletal material you recently came across in the Lesedi Chamber shares similarities with Homo naledi and adds to this statement. What can/does this new discovery tell us about human evolution in Africa?

I think the clear picture that has come from both the discovery of Australopithecus sediba and Homo naledi is that the story of human evolution is not a simple, linear, straightforward one but that ours is a complex history. Naledi and sediba show us that there is more to be found – it’s clear that we don’t really know their ancestral history and the few fossils of other species found across Africa don’t help us much with interpreting where they fit in our family tree – and that’s exciting. We currently are back in the Dinaledi and Lesedi Chambers and making new discoveries – particularly exciting is we seem to have strong evidence that Homo naledi did indeed come down the narrow chute the way our “underground astronauts” come – and that is wonderful and hard to explain – but it’s exciting!

This has been a contentious issue: whether or not the fossil remains were “placed” there or were brought in by scavengers. What is also not clear is if the book was published before the new dates became available, or not.  I will have to buy the book to find that out.  While the rest of the interview is a tad unsubstantive, it is interesting.

New Study on Homo naledi

Lauren Schroeder and colleagues have published a report on the skull of Homo naledi, in which they address the characteristics and attempt to place them in a taxonomic context, using morphometric analysis.  From the abstract:

Our results indicate that, cranially, H. naledi aligns with members of the genus Homo, with closest affiliations to H. erectus. The mandibular results are less clear; H. naledi closely associates with a number of taxa, including some australopiths. However, results also show that although H. naledi shares similarities with H. erectus, some distances from this taxon – especially small-brained members of this taxon – are extreme. The neighbor joining trees place H. naledi firmly within Homo. The trees based on cranial morphology again indicate a close relationship between H. naledi and H. erectus, whereas the mandibular tree places H. naledi closer to basal Homo, suggesting a deeper antiquity. Altogether, these results emphasize the unique combination of features (H. erectus-like cranium, less derived mandible) defining H. naledi. Our results also highlight the variability within Homo, calling for a greater focus on the cause of this variability, and emphasizing the importance of using the total morphological package for species diagnoses.

Another major finding of the study is that a grouping of H. naledi and specimens of Homo erectus "exceeds, in many instances, what we would expect if this grouping represented a single species."  Recall that we have zero idea how old this find is and, to the extent that this is possible, are trying to place this skull using only taxonomic analysis. Nonetheless, it gives us more information about this stage of hominin evolution and suggests that there was considerable variation of morphs running around during the transition from the australopithecines to early Homo. 

Lauren Saville: The Importance of Teaching Human Evolution

Lauren Saville has written a post for NCSE titled "The Importance of Teaching Evolution."  Inevitably, the post deals not just with human evolution, but with climate change as well because, just as rejection of human evolution goes hand in hand with climate change skepticism on the right, acceptance of the two go hand in hand on the left.  So, why should we teach human evolution?

From an early age we wonder where we come from; evolution explains that for us. From the amazing array of fossils that have been found in Africa, Asia, and Europe we can piece together our evolutionary lineage from Australopithecus to early Homo sapiens and explore the different species that branched off in between. By studying the fossil record we can understand when we began walking upright, by noting all the huge morphological changes that distinguish us from other great apes, such as our wide bowl-shaped pelvis, big toes in line with the rest of our feet and shorter arms. We can see when our brain size increased (when Homo erectus came about) and the subsequent huge change in our technology. As they say, the rest is history.

Tapping into our inherent curiosity about our history and origins is a great way to get students excited about science. Who does not want to know why we do the things we do and look the way we do? Learning about our own evolution helps students feel connected to science.

I would add that one of the reasons we should teach human evolution is because it places us in the wide pantheon of evolution on the earth, which began some 3.5 billion years ago. It gives us an idea of the vastness of time. Humans, in their (relatively) current form, have been around for almost 200 thousand years. Our genus has been around for over 2 million years. How long is that? If you started counting by ones out loud, it would take you twenty-two days of straight counting to get to two million.

To count to one billion would take you 31 years!!

Evolution has been going on for three and a half times that long. We are part and parcel of the grand design of life and should take joy in that.

H. floresiensis Not As Young or As Unique As We Thought

In other words, so much for the pathology argument.  Many news outlets, National Geographic being one of them, are reporting on new fossils that closely match those of Homo floresiensis that were found at Liang Bua Cave on the island of Flores in the late 1990s.  Adam Hoffman writes:

The 700,000-year-old human remains are the first found outside Liang Bua cave, the site on Flores that yielded the original hobbit fossils. The much older samples show intriguing similarities to H. floresiensis, including their small size, and so provide the best evidence yet of a potential hobbit ancestor.

“Since the hobbit was found, there have been two major hypotheses concerning its ancestry,” says Gerritt van den Bergh, an archaeologist at the University of Wollongong in Australia and a contributor to the work.

According to one theory, H. floresiensis is a dwarfed form of Homo erectus, an ancient human relative that lived in East Asia and parts of Africa until about 143,000 years ago. But other researchers think the hobbits evolved from even earlier, smaller-bodied hominins such as Homo habilis or Australopithecus.

“These new findings suggest that Homo floresiensis is indeed a dwarfed form of Homo erectus from Java, a small group of which must have gotten marooned on Flores and evolved in isolation,” van den Bergh says.

The article goes on to note that the competing argument, that the fossils of Liang Bua represent some kind of pathological condition, and that they maintained this condition for some 700 ky, is now untenable. Clearly this is a side-branch of human evolution.The other key finding is that they also had stone tools, specifically a “straightforward core and flake” technology. Further, the tools show a striking similarity to those found at Liang Bua, suggesting that there was remarkable cognitive "stability" in this population. 

The more we think we know about human evolution, the less, it turns out, that we do.  For now, the entire article is available from Nature for free here. 

Humans and Fire

It had been conventional wisdom that the origin of bipedality occurred in a forest/fringe environment and that a move to the savannah during the dry-out at the end of the Pliocene accelerated the evolution of humans.  That was thrown into turmoil when it was discovered that Ardipithecus ramidus possessed facultative bipedal characteristics at 4.4 million years but lived in an entirely forested environment.

Now, it seems, the savannah is seen as playing a different role in human evolution.  Charles Q. Choi, of Scientific American writes:

A longtime theory holds that early humans discovered how to use fire accidentally—perhaps while making stone tools they found that striking rocks against each other could generate sparks, and then gradually learned fire had many uses.

The problem with such serendipity-based explanations is that they "raise more questions than they answer," says evolutionary anthropologist Christopher Parker at the University of Utah in Salt Lake City. For example, these theories do not address when or where the discovery might have occurred, why it did not happen earlier or why other animals that use stone tools—chimpanzees, capuchin monkeys, crab-eating macaques and sea otters are known to do so—did not also develop fire use, Parker notes.

Parker and his colleagues suggest in a study published in the April Evolutionary Anthropology that humans developed fire use as a natural response to environmental changes. Previous research found that roughly 3.6 million to 1.4 million years ago—as the genus Homo emerged in Africa—the continent regularly experienced bouts of aridity, causing forests to shrink and dry grasslands to spread. Earlier studies suggested these climate shifts may have driven humanity’s ancestors away from a life climbing trees and toward one of walking upright on the ground, Parker says.

Yes, but there have been, as alluded to above, issues with these previous studies. If bipedality originated in the forest, as a response to who-knows-what, then they already possessed it when the drying out began. But this is not the crux of Parker's research:

Parker and his colleagues suggest in the new study that our ancestors not only grew accustomed to fire but learned to exploit it as a naturally occurring resource. This adaptation, called pyrophilia, may have set the stage for more active and deliberate human use of fire.

The research team's models suggest early humans benefited from wildfires in a number of ways: The blazes would have made it easier to find food, much as Martu Aboriginal women in Australia still rely on fire to clear brush for more efficient hunting. The models also indicate that early humans might have combed the charred remains of wildfires to dine on animals, seeds, nuts and tubers cooked in the flames—benefitting from a chemical process that not only makes many foods easier to digest but kills germs and neutralizes some toxins.

This has not been proposed before and it will be interesting to see if more evidence of this is found. Read the whole thing.

Humans and Meat

New research by Dan Lieberman and Katherine Zink strongly supports what we have suspected for quite some time, that a substantial change in diet of early hominins led to rapid evolution in brain size and social structure.  Brian Handwerk of Smithsonian writes:

After measuring chewing and biting in modern humans, scientists found that a diet that includes one-third raw meat requires far less chewing and bite force exertion than meals of tubers alone. The researchers suggest that with the advent of stone tools, ancient human relatives were able to tenderize their food and make it far easier to chew and digest.

“An important step was just using a simple stone tool to cut our meat and bash our vegetables,” says Harvard University evolutionary biologist Daniel Lieberman.

The idea that fire allowed humans to cook their food and soften it that way has been around for quite some time and arguments usually point to the widespread use of fire toward the end of the Middle Pleistocene as the point where this begins to happen. This is the first time I have seen this argument extended to the early Pleistocene.The article continues:

“If I gave you a piece of raw goat, you would just chew and chew it, like a piece of bubble gum,” Lieberman explains. “Human teeth don't have the kind of shearing ability that, say, dogs' teeth have, and that is necessary to break down meat. With human chewing it just stays in a clump, and studies have shown how that makes digestion far less efficient.”

Cooking makes it easier to chew meat, but evidence suggests that the regular use of fire for cooking didn't pop up until perhaps half a million years ago—far later than the changes to H. erectus. Also, evidence from archaeological and paleontological research points to a spike in human meat consumption by at least 2.6 million years ago.

However, we have plenty of evidence that hominins had begun making stone tools some 3.3 million years ago. Those tools could have been used as pounders to tenderize foods, a practice seen in modern chimps. Flaked tools can also slice foods into easily chewable pieces or remove skin, cartilage and other bits that are harder to chew.

“It's not a coincidence that the oldest evidence for eating meat shows up around the same time as tools,” Lieberman says. “We know that the evolution of meat-eating basically required stone tools. And that had a huge effect on our biology.”

When my wife makes a dish involving chicken breasts, the first thing she does is pound them.  This makes it much softer and easier to eat. 

This is one of the principle reasons I tend to regard arguments in favor of vegetarianism somewhat warily. It is simply not in our nature or physiology to be that way. You can be one, if you wish, but that is not the natural state of things.

Modern Hand Digit at 1.84 Mya

A story in Lab Equipment has spotlighted new evidence that modern human morphology was present in early hominins at 1.84 million years ago.  From the story:

“The new Olduvai fossil represents the earliest known hominin hand bone with (modern human-like) appearance,” they wrote. “Our results, along with the archaeological record, reveal that instead of following an orderly trend, eventually culminating in the modern human condition, some ‘primitive’ hand bone morphologies persisted side-by-side with (modern human-like) hand bone morphologies well after the first appearance of stone tools and zooarchaeological evidence of their use for butchery by at least (2.6 million years ago).”

This makes sense. Evolution happens at the trait level, not the species level. There are numerous examples of some traits becoming more modern over time, while some retained archaic dimensions.What is not clear is whether or not it is from early Homo or Australopithecus (Paranthropus) boisei.  If it is from Paranthropus, then the modern morphology extends back at least to the point where the later diversification of australopithecines occurred, between 2.5 and 3.0 mya and, perhaps, longer. 

New Jawbone Fills Gaps, Raises Questions

A group working in the Afar Triangle has discovered a mandibular fragment with associated teeth that show strong affinities to early Homo.

The catch is that the provisional date for this specimen is 2.8 million years. Writes Pallab Ghosh for the BBC:

The head of the research team told BBC News that the find gives the first insight into "the most important transitions in human evolution".

"This is the most important transition in human evolution”

Prof Brian Villmoare University of Nevada

Prof Brian Villmoare of the University of Nevada in Las Vegas said the discovery makes a clear link between an iconic 3.2 million-year-old hominin (human-like primate) discovered in the same area in 1974, called "Lucy".

Could Lucy's kind - which belonged to the species Australopithecus afarensis - have evolved into the very first primitive humans?

"That's what we are arguing," said Prof Villmoare.

This find in the north of the continent strains, almost to the breaking point, the argument that Australopithecus sediba is the best candidate for being ancestral to early Homo. That find came from a cave in South Africa and, up to this point, all of the respective species of Australopithecus have been fairly tightly geographically restricted in their home ranges. The distinct possibility exists that only A. afarensis is ancestral and ALL other australopithecines went extinct, but we will have to wait for considerably more comparative studies on the morphology of the jaw to make any sort of rudimentary arguments along those lines. 

BioLogos, Ken Ham and David Menton—A Response, Part III

This is the third part of my response to David Menton's post on human origins, cited by Ken Ham in his swipe at BioLogos.  Part One his here, Part two is here.We have been proceeding, point by point.

Point 6.  Menton writes:

Evolutionists are particularly interested in the angle at which the femur and the tibia meet at the knee (called the carrying angle). Humans are able to keep their weight over their feet while walking because their femurs converge toward the knees, forming a carrying angle of approximately nine degrees with the tibia (in other words, we’re sort of knock-kneed). In contrast, chimps and gorillas have widely separated, straight legs with a carrying angle of essentially zero degrees. These animals manage to keep their weight over their feet when walking by swinging their body from side to side in the familiar “ape walk.”

Evolutionists assume that fossil apes with a high carrying angle (humanlike) were bipedal and thus evolved into man. Certain australopithecines (apelike creatures) are considered to have walked like us and thus to be our ancestors largely because they had a high carrying angle. But high carrying angles are not confined to humans—they are also found on some modern apes that walk gracefully on tree limbs and only clumsily on the ground. 

Living apes with a high carrying angle (values comparable to man) include such apes as the orangutan and spider monkey—both adept tree climbers and capable of only an apelike bipedal gait on the ground. The point is that there are living tree-dwelling apes and monkeys with some of the same anatomical features that evolutionists consider to be definitive evidence for bipedality, yet none of these animals walks like man and no one suggests they are our ancestors or descendants. 

Let's leave aside the fact that the spider monkey is not an ape, although it speaks to Menton's understanding of primate taxonomy.  Menton follows the above quoted passage with some of the differences between the human feet and hips and, largely, gets them right.  But that makes his comments about the carrying angle all the more peculiar.  In hominin biomechanics, the legs do not operate independently of the hip, or of the feet.  He comments that there are apes that seem to have similar carrying angles and yet can't walk bipedally to save their lives.  He even writes that, given the ape pelvis, there is no way to walk like a human.  He is right about their hips, they are long and narrow.  He is right about their feet, they have opposable halluxes and the toes are not straight and narrow.  These features, in combination would keep anyone from walking upright like a human, no matter what their carrying angle was.  Walking gracefully on tree limbs is not the same thing as walking gracefully on the ground.  He isolates the carrying angle and seems to think that, because it might be similar in apes and humans, our analyses of the gait differences between the two are suspect.  That is absurd. 

And this brings up another problem.  He states that australopithecines were considered bipeds because of their carrying angle.  What he doesn't mention is that we have many fossil finds that indicate that not only did they have high carrying angles, they had all of the other adaptations for bipedalism.  They had human-like hips, and feet that are mostly human-like and, unmentioned by Menton, STS-14, an almost complete australopithecine vertebral column, shows that they had the double-s curve of the spine that we have and that are critical to bipedal locomotion.

Further, in his discussion of the skull, he ignores the placement of the foramen magnum, which is critical to understanding primate morphology.  The foramen magnum is the hole in the skull through which the spinal cord descends into the body.  In non-human primates (all non-human primates!) the hole is at the back of the skull, to facilitate quadrupedal locomotion.  In all hominins, fossil or otherwise, the hole is at the bottom of the skull, reflecting a bipedal gait.  This is yet another thing that raised a red flag with Raymond Dart on the Taung skull—the hole was at the bottom of the skull, as in humans, not the back, as in baboons—and he noted it accordingly.  This is a critical difference between apes and humans and Menton fails to mention it. 

Point 7: The second major section of Menton's article is “Only Three Ways to Make an Ape-Man.” He writes:

Knowing from Scripture that God didn’t create any apemen, there are only three ways for the evolutionist to create one:

1. Combine ape fossil bones with human fossil bones and declare the two to be one individual—a real “apeman.”
2. Emphasize certain humanlike qualities of fossilized ape bones, and with imagination upgrade apes to be more humanlike.
3. Emphasize certain apelike qualities of fossilized human bones, and with imagination downgrade humans to be more apelike.

These three approaches account for all of the attempts by evolutionists to fill the unbridgeable gap between apes and men with fossil apemen.

This is the hallmark of modern young earth creationism: to jettison all of modern science in favor of a particular and peculiar hermeneutic involving biology and its evolutionary history.  He reasons that since God would not have ever created a transitional form like an “ape-man,” humans must have fabricated them. How exactly does he know that God didn't create “ape-men?”  It is difficult to be charitable toward Menton regarding this section because he is, at once, so pompous, so insulting and engages in so much obfuscation that one is left wondering if he displays any intellectual integrity whatever. For his first point, he dredges up the Piltdown hoax, writing: 

The whole thing turned out to be an elaborate hoax. The skull was indeed human (about 500 years old), while the jaw was that of a modern female orangutan whose teeth had been obviously filed to crudely resemble the human wear pattern. Indeed, the long ape canine tooth was filed down so far that it exposed the pulp chamber, which was then filled in to hide the mischief. It would seem that any competent scientist examining this tooth would have concluded that it was either a hoax or the world’s first root canal! The success of this hoax for over 50 years, in spite of the careful scrutiny of the best authorities in the world, led the human evolutionist Sir Solly Zuckerman to declare: “It is doubtful if there is any science at all in the search for man’s fossil ancestry.”1

The Piltdown hoax celebrated its one hundredth anniversary two years ago, in 2012.  Far and away (in my opinion) is Frank Spencer's account of the hoax, called Piltdown: A Scientific Forgery. Here are details that Menton conveniently leaves out of the account.  When the Piltdown remains were found, there were no dating methods and very few fossil human remains of any kind.  Nonetheless, it sparked controversy when it was discovered by Charles Dawson and, as initially reconstructed by Grafton Elliot Smith, looked remarkably modern in appearance.  It was not until the jaw was found, conveniently missing the ascending ramus, and incorporated into the find that it took on a more ape-like morphology.  Once Piltdown was described, however, it was locked away in a vault and access was very limited. That is where the problems began.  At this point, a critical thing happened.  Dawson died, in 1915.  Common consensus is that Dawson was the perpetrator and took  this information with him to the grave.

As I noted here, as time went by, more and more human ancestor remains were discovered in Africa, Asia and continental Europe.  As this happened, two things became clear: Nothing even remotely resembling Piltdown was found elsewhere and nothing remotely resembling Piltdown was found in England.  As human lineage trees were constructed throughout the 1930s and 1940s, Piltdown's peculiarity grew and researchers struggled to place it within any context.  Franz Weidenreich, in his excellent monograph on the Homo erectus remains from Zhoukoudian, questioned the dating of the find and had mused, even since the 1920s,  that it might be a combination of human and ape parts.  Ales Hrdlicka, the head of the American Museum of Natural History, actually uttered the dreaded word “fake.”

Owing to all of these concerns, in 1949, Kenneth Oakley, then in possession of the ability to use a brand-new dating method, fluorine analysis, was successful in getting access to the skull on the condition that he not damage it in any way.   This analysis suggested that the bones were less than 50,000 years old.  On the strength of this, and since nobody could believe that a fossil ape had roamed the English countryside at this time, further, more in-depth analyses were undertaken.  In addition to using fluorine, he and Wilfred Le Gros Clark were able, for the first time, to use a powerful electron microscope, which had been invented in 1926 but was not in widespread use until around 1939.  It was only then that they could discern what Menton seems to think anyone could have seen: that the teeth had been filed down and the jaw stained and fractured.

Was this embarrassing?  Yup, sure was.  But Menton also fails to mention that the hoax was uncovered by scientists using the scientific method and that the primary reason it was uncovered in the first place is that we knew, even then, enough about human evolution, based on the fossil record, to tell that there was something wrong with Piltdown.  He also fails to mention that the quote by Solly Zuckerman is 44 years old (!) and that Zuckerman even admits that his view was soon in the minority.  Zuckerman, additionally, is remarking on why Piltdown escaped notice, and it is quite clear from his other writings that he accepted human evolution without question.  Menton, once again, fails to include these facts in his post. 

Part IV here.

New Study: Ardipithecus ramidus Derived In Human Direction

According to Bill Kimbel and colleagues, the skull of Ardipithecus ramidus shows tell-tale signs of being derived in the human direction away from great apes.  From Science Daily:

White's field-research team has been recovering fossil remains of Ardipithecus ramidus in the Middle Awash research area, Ethiopia since the 1990s. The most recent study of the Ardi skull, led by Suwa, was published in Science in 2009, whose work (with the Middle Awash team) first revealed humanlike aspects of its base. Kimbel co-leads the team that recovered the earliest known Australopithecus skulls from the Hadar site, home of the "Lucy" skeleton, in Ethiopia.

"Given the very tiny size of the Ardi skull, the similarity of its cranial base to a human's is astonishing," says Kimbel.

The cranial base is a valuable resource for studying phylogenetic, or natural evolutionary relationships, because its anatomical complexity and association with the brain, posture and chewing system have provided numerous opportunities for adaptive evolution over time. The human cranial base, accordingly, differs profoundly from that of apes and other primates.

In humans, the structures marking the articulation of the spine with the skull are more forwardly located than in apes, where the base is shorter from front to back and the openings on each side for passage of blood vessels and nerves are more widely separated.

Given that the post-cranial remains from Ardipithecus suggest facultative bipedalism, this is not so surprising. If you are going to walk upright at all, you need to be able to see where you are going. This information, in conjunction with the new appraisal of the Orrorin tugenensis remains strongly suggests that, while Orrorin was at or near the junction of the last common ancestor, Ardipithecus, at 1.6 million years later, is quite a bit beyond it. It also reinforces what a terrible model the modern apes are for early human morphology.

Environment Highly Variable For Early Humans

The Telegraph is reporting a story out of PNAS that suggest that the environment was highly variable during a critical point in our evolution.  They write:

The early landscape shifted between woodland to grassland half a dozen times over 200,000 years, meaning man had to adapt to survive.

Experts from Penn State university say that this may have set the tone for the rapid evolution which then took place.

Writing in the Proceedings of the National Academy of Sciences, Clayton Magill said: "The landscape early humans were inhabiting transitioned rapidly back and forth between a closed woodland and an open grassland about five to six times during a period of 200,000 years.

"These changes happened very abruptly, with each transition occurring over hundreds to just a few thousand years."

The findings appear to contradict previous theories which suggest evolutionary changes were gradual, and in response to either long and steady climate change or one drastic change.

The general consensus is that that there was a gradual drying out of the environment that led to the hominins taking over the savanna.  It is not clear that these hypervariable changes will correspond to abrupt changes in hominin form but it could partially explain the somewhat sudden appearance on early Homo.  We shall see.  

Crocodile From Hell, East African Version

Again from Discovery News, it turns out that there was a horned crocodile that lived around the time of the Australopithecines and likely ate more than a few of them for lunch. Jennifer Viegas writes:

Remains of the enormous horned croc, named Crocodylus thorbjarnarsoni, were unearthed in East Africa. The impressive aquatic reptile exceeded 27 feet long and is described in the latest Journal of Vertebrate Paleontology.

The croc was the dominant predator of its ecosystem, so there is little doubt that it preyed upon our distant ancestors, especially since remains of Australopithecus (a now-extinct genus of hominids) were found nearby.

These relatively tiny individuals would have had no choice but to enter the crocodile's territory for much needed water.

These early hominins had to contend with large cats on the savanna as well so survival was never guaranteed.

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Did Competition Put Us On Our Feet?

Simply, yes. That is not earth-shattering. Cambridge News has a story on work done with chimpanzees that seems to confirm that behavioral alterations in higher level primates help with competitiveness. They write:

Anthropologists studying chimpanzees found the great apes, who usually walk on all fours, walk upright and free their hands for carrying when they need to grab more hard-to-find resources in one go, in the face of competition.

The team from the University of Cambridge and Kyoto University in Japan believe the benefit of “first come, first served” and getting a bigger share of scarce food supplies could, over a long period of time, have led some of our earliest “hominin” ancestors to evolve into “bipedal” primates walking on two legs permanently instead of four.

This has always been part of the bipedality model, that early hominins exploited the forest/fringe environment where they could get what they needed from the trees and from the savannas. The fact that Ardipithecus ramidus demonstrated bipedality in a forested environment sort of threw cold water on the more conservative of those models but it is also clear that even the level of bipedality continued to evolve over time and that, by the time later australopithecines had completely human, obligate bipedal locomotion, these hominins were living in the open and competing for those resources. It was at this point that our brains began to expand as well.

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New BioLogos Post is Up

My new post on early Homo is up at BioLogos. As always, comments are welcome here and there.

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Frame-Shift Mutation Linked to Sympatric Speciation in Early Homo?

According to (new?) research from the University of California, San Diego School of Medicine, a mutation creating a slightly different sugar molecule may have caused a reproductive barrier between those that had it and those that didn't in our human ancestors, possibly influencing the split between early Homo and australopithecines. Stephanie Pappas of Live Science writes:

The mutation tweaked one type of sugar molecule, Neu5Gc, produced by early hominids, the first great apes. About 2 million or 3 million years ago, just as human ancestors Homo ergaster and Homo erectus emerged in Africa, a genetic mutation halted the production of this molecule, and the prehuman immune system began to recognize it as a threat. As a result, researchers find, some hominids would no longer have been able to mate and produce offspring with other populations, potentially driving early humans apart from other apes."Over time, this incompatibility would reduce and the eliminate individuals with Neu5Gc," study researcher Pascal Gagneux of the University of California, San Diego, said in a statement.

If the date is closer to three million years, it would have considerable implications for the emergence of Homo. There are many theories about where early Homo came from and what led to the transition from Australopithecus to what became the earliest members of our line. This will shed some light on these ideas and, hopefully, spur more research in this area.

Interestingly, this research is not as new as the story makes it out to be. There was a paper written by A. Varki in 2001 that dealt directly with this data. It can be found here. Varki, however, did not make the connexion with immune suppression response but focused, rather, on how the mutation affected brain evolution.

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New BioLogos Post Is Up

The next BioLogos post on the Dispersal of the Australopithecines is up. As always, comments are welcome both there and here.