Neandertal/Denisovan Ancestors Interbred With Unknown Hominin

As if the tangle of early archaic Homo sapiens relationships couldn't get any more confusing, evidence has now surfaced that the ancestors of both the Neandertals and Denisovans interbred with a hominin only known from its DNA signature.  From the University of Utah, through Science Daily:

For three years, anthropologist Alan Rogers has attempted to solve an evolutionary puzzle. His research untangles millions of years of human evolution by analyzing DNA strands from ancient human species known as hominins. Like many evolutionary geneticists, Rogers compares hominin genomes looking for genetic patterns such as mutations and shared genes. He develops statistical methods that infer the history of ancient human populations.

According to the article, Rogers performed a study that argued that Neandertals and Denisovans separated earlier than has previously been suggested but that his evidence for this was thin.

The new study has solved that puzzle and in doing so, it has documented the earliest known interbreeding event between ancient human populations -- a group known as the "super-archaics" in Eurasia interbred with a Neanderthal-Denisovan ancestor about 700,000 years ago. The event was between two populations that were more distantly related than any other recorded. The authors also proposed a revised timeline for human migration out of Africa and into Eurasia. The method for analyzing ancient DNA provides a new way to look farther back into the human lineage than ever before.

"We've never known about this episode of interbreeding and we've never been able to estimate the size of the super-archaic population," said Rogers, lead author of the study. "We're just shedding light on an interval on human evolutionary history that was previously completely dark."

According the Rogers, the DNA evidence puts the final nail in the coffin of the complete Out-of-Africa replacement model of modern human origins:

The researchers also proposed there were three waves of human migration into Eurasia. The first was two million years ago when the super-archaics migrated into Eurasia and expanded into a large population. Then 700,000 years ago, Neanderthal-Denisovan ancestors migrated into Eurasia and quickly interbred with the descendants of the super-archaics. Finally, modern humans expanded to Eurasia 50,000 years ago where we know they interbred with other ancient humans, including with the Neanderthals.

This was likely something like Homo antecessor.  As is also true with the Chinese evidence, this evidence suggests that throughout human evolutionary history, there has never/rarely been a time when these groups of archaic and early modern Homo sapiens could not/did not interbreed. As J. Lawrence Angel once said “When two groups of people meet, they may fight, but they will always mate.”

The Science Advances article is open access. 

http://dx.doi.org/10.1126/sciadv.aay5483

Evolution of the Human Foot

Nature News has an interesting examination of how the human foot evolved the arch, the singular most important aspect in the ability to perform bipedal locomotion.  Glen Lichtwark and Luke Kelly write:

Humans evolved to walk and run effectively on the ground using two feet. Our arched foot, which is not a characteristic of other primates, is a unique feature crucial for human bipedalism. The arch provides the foot with the stiffness necessary to act as a lever that transmits the forces generated by leg muscles as they push against the ground. The arch also retains sufficient flexibility to function like a spring to store and then release mechanical energy. Writing in Nature, Venkadesan et al.1 present a new view of how foot stiffness is regulated. Their finding not only has exciting implications for understanding foot evolution, but also provides a possible framework when considering foot health and how to design better footwear.

The authors note that there are two different arches present in the human foot, the longitudinal arch, which is more familiar to people and the transverse arch. They argue that the transverse arch (across the top of the foot) is as important for walking as the longitudinal arch. The authors note that the transverse arch has been neglected in sports and medicine and that more research needs to be done in this area. 

Upright Ape?

Multiple outlets are reporting on the discovery of a fossil ape that appears to have at least a partially facultatively bipedal stance.  Here is the Fox News version of events:

The remains of an 11 million-year-old ape suggest that our ancestors started to stand upright millions of years earlier, according to scientists.

A team of researchers claims the fossilized partial skeleton of a male ape that lived in the humid forests of what is now southern Germany bears a striking resemblance to modern human bones. In a paper published on Wednesday by the journal Nature, they concluded that the new species — dubbed Danuvius guggenmosi — could walk on two legs but also climb like an ape.

The findings “raise fundamental questions about our previous understanding of the evolution of the great apes and humans,” Madelaine Boehme of the University of Tuebingen, Germany, who led the research, told The Associated Press.

Here is how the Nature paper actually reads:

Here we describe the fossil ape Danuvius guggenmosi (from the Allgäu region of Bavaria) for which complete limb bones are preserved, which provides evidence of a newly identified form of positional behaviour—extended limb clambering. The 11.62-millionyear-old Danuvius is a great ape that is dentally most similar to Dryopithecus and other European late Miocene apes. With a broad thorax, long lumbar spine and extended hips and knees, as in bipeds, and elongated and fully extended forelimbs, as in all apes (hominoids), Danuvius combines the adaptations of bipeds and suspensory apes, and provides a model for the common ancestor of great apes and humans.

First, this is way-the-heck back there, some five and a half million years before the first actual evidence of bipedalism (Orrorin). Second, there are no “hip” remains. The only post-cranial remains are long bones.  Much is inferred.  In hominins, the femoral neck and the connection to the femoral head provide much diagnostic locomotion information.  The fossil remains for this region are very scant, consisting only of a partial head.  Much of the argument for even some bipedality rests with the tibial angle, to wit:

The near perpendicular tibial angle is a shared character between hominins and Danuvius and supports the inference of a habitual valgus knee position and bipedalism for the new genus.

I think a new genus designation is certainly warranted. I have grave reservations about the “bipedalism” designation. We have possible evidence from Crete at 5.5 million years for bipedalism in the form of footprints. That is as far north as it gets.  All of the other evidence we have for the emergence of hominins and bipedalism comes from North Africa.  It is far more likely that this represents an independent adaptation/homoplasy for this hominoid.   If we had more evidence from later in the Miocene or, better yet, the Pliocene, then this might carry more weight.

New Poll From Gallup on Human Origins

Gallup has released a new poll on what people think about human evolution.  Here is their takeaway blurb:

Forty percent of U.S. adults ascribe to a strictly creationist view of human origins, believing that God created them in their present form within roughly the past 10,000 years. However, more Americans continue to think that humans evolved over millions of years -- either with God's guidance (33%) or, increasingly, without God's involvement at all (22%).

Beyond this are details in the numbers.The poll was conducted from June 3-16 and contained a random sample of 1015 adults.  Some of this is not new and has changed little since the last poll.  There is a high correlation between those with a college education and those who accept human evolution.  The correlation is also high between those who have no religious affiliation and those who accept human evolution.

Other interesting tidbits from the attached PDF:

• Acceptance of God-guided human evolution does not seem to change with political party affiliation, gender or ethnic background
•  Acceptance of God-guided human evolution rises only slightly with age
• The idea that God created humans in their present form drops substantially from 55% (Republican) to 34% (independent and Democrat) as well as ideology (54% Republican, 29% democrat)

There are more observations buried in the data. Have a look.

New Species of Hominin Found in Phillipines

From a story in UPI:

At the completion of excavations on the island of Luzon, scientists had unearthed several teeth, part of a thigh bone, and a few hand and foot bones. The fossils comprise the "the earliest direct evidence of a human presence in the Philippines," according to the latest study.

The fossilized bones, dated to between 67,000 and 50,000 years ago, feature a mix of anatomical characteristics, some that recall more primitive hominins and others similar to those of more modern human species.

Callao Cave is toward the northern tip of Luzon. The corresponding article from Nature seems to indicate that the fossil remains from this cave are “all over the map.”  The premolars indicate size and shape affinities to later Homo, while some of the characteristics are australopithecine (!).  This is also true of the hand elements. 

Although we have found human fossil remains in East Asia for some time (1896 on), there are large gaps in our knowledge, especially from the first appearance of Homo erectus to the advent of modern humans.  These fossils, while giving us more  information than we had, muddy the waters a bit.  Once upon a time, Grover Kranz (RIP) tried to convince me that australopithecines could be found in East Asia, but his evidence was based on a badly crushed occipital bone. 

It is clear from the presence of H. floresiensis and the current evidence that primitive traits were being retained in some groups but, as the authors point out, we need quite a bit more fossil material to make any definitive assessments. 

British Columbia Leading War in Canada against Creationism...Or Is It?

Support for young earth creationism is, apparently, somewhat variable when it comes to the different Canadian provinces.  This is not surprising, since one might reasonably same the same thing about the fifty United States.  Burnaby.com is reporting on efforts in British Columbia to assert control over this situation.  Mario Canseco writes:

There are many reasons for these regional variances. Over the past two decades, British Columbia has positioned itself as closest to secularism than any other region of Canada. Fewer British Columbians describe themselves as having “a religion” every time the census rolls around. Still, the last municipal election saw candidates running for school board seats – and winning – after outlining creationist views. Quebec has always been a land of contrasts when it comes to religion. The presence of a crucifix inside the National Assembly is debated extensively in a province where fewer residents are attending church services than ever before.

The odd thing here is that the writer of the piece has invoked a non-sequitur in the interpretation of the data, it seems.  He remarks that 55% of residents of BC would "keep creationism out of schools," but that conclusion doesn't follow from any of the graphs presented.  That is not the question asked.  The questions being asked are whether or not humans evolved or were created within the last 10,000 years.  While it is quite true that the two concepts are similar, one does not necessarily follow from the other.

Furthermore, it is not clear where he is getting his 55% number from, nor where he concludes that BC is leading the pack.  Eyeballing the graphs seems to indicate that BC is behind Alberta and Quebec in their acceptance of human evolution.

I am not sure I would put a lot of faith in this. 

New Laetoli Footprints Demonstrate Full Bipedality

A story running in Newsweek and the Washington Post (and other outlets, presumably), details research into the newly discovered fossil footprints at Laetoli dated to 3.6 mya that clearly show a modern human gait.

Two sites in Laetoli, Tanzania, feature footprints of human ancestors who lived about 3.6 million years ago. They were members of the genus Australopithecus. That's the genus of “Lucy,” the 3.2 million-year-old human ancestor whose fossilized bones were discovered in Ethiopia in 1974.

David Raichlen, an evolutionary anthropologist at the University of Arizona, has studied the Laetoli footprints and compared them to footprints made by human volunteers in laboratory settings. He examined footprints of individuals walking normally and also those walking with bent knees and bent hips. (Scientists who study locomotion use the acronym BKBH). The Laetoli footprints more closely match modern human footprints.

“Upright, humanlike bipedal walking goes back 4 to 5 million years,” Raichlen told The Washington Post in advance of a symposium on the evolution of human locomotion, which took place Sunday at the Experimental Biology 2018 conference in San Diego.

This dovetails with the recent findings that Ardipithecus, a hominin dated to around 4.4 mya, likely could travel equally well on the ground or in the trees.  Oddly, the WaPo article doesn't mention this.  

5.7 Million Year-Old Human Footprints Found on Greek Island of Crete

Great Googlymoogly!  This one is lighting up all over the Internet.  Fossil footprints have been found in the southern Greek Island of Crete, near the village of Trachilos, that appear to have the distinctive heel-toe-off gait of bipedal humans.  The catch? The prints are 5.7 million years old!  From PhysOrg:

Human feet have a very distinctive shape, different from all other land animals. The combination of a long sole, five short forward-pointing toes without claws, and a hallux ("big toe") that is larger than the other toes, is unique. The feet of our closest relatives, the great apes, look more like a human hand with a thumb-like hallux that sticks out to the side. The Laetoli footprints, thought to have been made by Australopithecus, are quite similar to those of modern humans except that the heel is narrower and the sole lacks a proper arch. By contrast, the 4.4 million year old Ardipithecus ramidus from Ethiopia, the oldest hominin known from reasonably complete fossils, has an ape-like foot. The researchers who described Ardipithecus argued that it is a direct ancestor of later hominins, implying that a human-like foot had not yet evolved at that time.

The new footprints, from Trachilos in western Crete, have an unmistakably human-like form. This is especially true of the toes. The big toe is similar to our own in shape, size and position; it is also associated with a distinct 'ball' on the sole, which is never present in apes. The sole of the foot is proportionately shorter than in the Laetoli prints, but it has the same general form. In short, the shape of the Trachilos prints indicates unambiguously that they belong to an early hominin, somewhat more primitive than the Laetoli trackmaker. They were made on a sandy seashore, possibly a small river delta, whereas the Laetoli tracks were made in volcanic ash.

And now, the other shoe.  How do we know how old the fossil footprints are?  

The coastal rocks at Trachilos, west of Kissamos Harbour in western Crete (Fig. 1a–c), lie within the Platanos Basin, and present a succession of shallow marine late Miocene carbonates and siliciclastics of the Roka Formation, a local development of the Vrysses Group (Freudenthal, 1969 ; van Hinsbergen and Meulenkamp, 2006; Figs. 1d, e and 3a, b). At the top, this marine succession terminates abruptly in the coarse-grained terrigenous sedimentary rocks of the Hellenikon Group (Figs. 1d and 3e, f), which formed by the desiccation of the Mediterranean Basin during the Messinian Salinity Crisis (van Hinsbergen and Meulenkamp, 2006), an event dated to approximately 5.6 Ma (Govers, 2009). The succession (Fig. 1d) contains an emergent horizon with well-preserved terrestrial trace fossils and microbially induced sedimentary structures (Fig. 3d) immediately overlying shallow water ripplemark structures (Fig. 3c).¹

So, the authors are a tad more circumspect than the writers of the PhysOrg story.  The authors posit two hypotheses for their results: 1. the tracks represent the gait of a basal hominin, which explains the non-divergence and shape of the big toe as well as the shape of the ends of the other toes, which resemble those of a human foot and not a non-human foot.  This fits approximately with the dates of the north African remains of Orrorin and, perhaps, that of Sahelanthropus (although that is pretty much a surface find).

The Messinian Crisis was a period of time during the Miocene epoch during which the Mediterranean Sea almost completely dried up.  This crisis began around 6 million years ago and ended around 5.3 million years ago with what is known as the Zanclean flood.  It is estimated that once the barrier at the Strait of Gibraltar was broken, the Mediterranean Sea refilled within two years, which means that the sea level rose at an estimated 30 feet per day.

Okay...now, lets go back here, to the story that came out about four months ago, establishing the possibility that the last common ancestor to apes and humans was in Europe.  In that study, a jaw with human root patterns and an isolated premolar that have both been attributed to Graecopithecus, were re-examined and found by the researchers to have hominin affinities, a surprising conclusion, given their age of 7.15 million years.  At the time that story appeared, I remarked that it was a bit of a stretch to hang one's hat on one premolar and partial ape-like mandible, but in the context of the new finds, maybe not so much.  This strengthens the (admittedly far-fetched) notion that our ancestors did, in fact, originate somewhere in southeast Mediterranean Europe and, over the course of the next two and half million years ago, migrated south to north Africa.

As Per Ahlberg was quoted as saying:

"This discovery challenges the established narrative of early human evolution head-on and is likely to generate a lot of debate. Whether the human origins research community will accept fossil footprints as conclusive evidence of the presence of hominins in the Miocene of Crete remains to be seen."

This is huge news.  Even if we can't place the LCA in southern Europe, we now have bipedalism extending back into the late Miocene. 


¹Gerard D. Gierliński et al, Possible hominin footprints from the late Miocene (c. 5.7 Ma) of Crete?, Proceedings of the Geologists' Association (2017). DOI: 10.1016/j.pgeola.2017.07.006

Will Moroccan Schools Teach Evolution Again

Writing for the Morocco World News, Amal Ben Hadda wonders if the discovery of more early modern human remains from the site of Jebel Irhoud will prompt the government to reintroduce evolution into the curriculum:

While these new discoveries are “shaking up” the scientific community, we should ask ourselves why these theories of evolution are not being taught in Moroccan schools. Why is this scientific approach to revealing the origin of humanity not considered in the manuals programs?

From a religious perspective, some Muslim scholars support the study of human evolutionary theory. The different levels of human conception are mentioned in many verses in the Quran. However, the exegeses of these verses have been influenced by Talmudic interpretations of the Torah and have been accepted as authentic versions of the human “genesis”. As an example of this influence, there is the creation of woman from Adam’s rib. This version, interpreted from the Torah and resumed by mainstream Islamic exegeses, doesn’t exist in the Quran.

In the original text of the Torah, the chapter Genesis shows in 1:27 that man and woman were conceived at the same level and no one is superior to another. However, this woman was diabolized by the patriarchal tradition. Only the version of the creation of woman from Adam’s rib named Eve is considered by the creationists as per the interpretations of the Genesis 2:23.

It is interesting to note that Islam seems to have the same issue that Christianity does in that modern interpretations of scripture have taken hold within a large subset of Muslims regarding this issue.  In Christianity, the days of creation were never originally written as seven sequential, 24-hour periods, yet that is the perspective of a large number of conservative evangelical Christians.  He author calls for a neutral interpretation of the Koran.  I would argue that we need a similar interpretation of the Bible. 

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. 

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.

New BioLogos Post on Xuchang Hominins is Up

My BioLogos post on the Xuchang hominins is up.  Comments welcome there and here.

The Onion: Archaeologists Uncover Last Human To Die Happy

The Onion has a story on how a team of archaeologists has discovered the last human to die happy:

“It’s truly incredible—Felix unequivocally demonstrates that early humans were still capable of dying completely fulfilled as late as the Upper Paleolithic,” said lead researcher Evgenia Halytsky, who went on to say that scientists had previously believed any such trait had disappeared many millennia earlier. “The vast majority of research points to our species almost never experiencing even a day of serenity for the last million years, so Felix totally upends any of our previous notions about human evolution.”

“To think that only 300 centuries ago, a human being actually died happy,” Halytsky added.

Researchers said that a spectral analysis of the remains indicated wear in Felix’s lower extremities consistent with a long, confident gait. Additionally, forensic odontology tests revealed that the man had never grinded his teeth, stunning scientists who had until now accepted that this behavior had become ubiquitous at roughly the same time humans developed abstract thought and the capacity to project into the future.

How does the phrase go: “Nobody ever lay on their deathbed thinking they hadn't spent enough time at the office.” Read the whole thing.

Increased Blood Flow to the Brain Helped Human Intelligence

PhysOrg is running a story about research that focuses on the role that blood flow played in the evolution of human intelligence.  Roger Seymour writes:

My eureka moment occurred when I realised that the size of an artery can be gauged by the size of the hole in a bone that it passes through.

This meant that the rate of blood flow to the brain could be measured by the sizes of the carotid canals in fossil skulls from human evolution.

It was a nice idea, but it took the enthusiasm of my student Vanya Bosiocic to turn it into a piece of research. She travelled to museums in Australia and in South Africa, gaining access to priceless fossil hominin skulls to make the measurements.

We found that the size of the carotid canals increased much faster than expected from brain size in 12 species of our human ancestors over a period of 3 million years.

While brain size was increasing 3.5 times, blood flow rate surprisingly increased sixfold, from about 1.2ml per second to 7ml per second.

This indicates that our brains are six times as hungry for oxygen as those of our ancestors, presumably because our cognitive ability is greater and therefore more energy-intensive.

We require a huge amount of fuel to keep our brains functioning and, while correlation is never causation, there is a distinct correlation between our massive increase in brain size during the late Pliocene/early Pleistocene and the appearance of more sophisticated stone tools, evidence of hunting and, eventually control of fire.  One of the other factors that may have had a role in this was the increase in protein intake in the form of animal meat.  Human evolution is a very complex entity because as we evolved and our brains increased in size, we began to manipulate our surroundings in a more significant way.  This, in turn, changed how we adapted and evolved in response to them. 

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. 

Human/Gorilla Split at Eight MYA?

Scientific American is running an article, which details work by Gen Suwa and colleagues, in the Afar Triangle, where nine gorilla-sized teeth were found in 2007 that have now been securely dated to around eight million years ago.  The researchers named the species Chororopithecus abyssinicus.  Charles Choi writes: 

The age and location of these fossils strengthen the view that the human and the modern ape lines originated in Africa and not Asia, the researchers said.

"Until now, no mammalian fossils south of the Sahara have been securely dated to 8 million to 9 million years ago," Suwa said. "Any and all fossils from this crucial time period of Africa would help unravel the story of human origins and emergence. These are the first such fossils."

In addition, until recently, "most scientists, especially geneticists, thought that the human-chimp split was as recent as 5 million years ago, and that the human-gorilla split was only about 7 million to 8 million years ago," Suwa said. "This contradicted the fossil record. For example, fossils thought to be on the human side of the split such as Ardipithecus kadabba from Ethiopia and Sahelanthropus from Chad were 6 million years old — or, in the case of the Chad fossil, perhaps 7 million years old."

The new findings suggest that Chororapithecus is 8 million years old, so "the actual gorilla-human split must then have been up to several million years before that," Suwa said.

More pieces to the puzzle. The other mystery, of course, is when the last common ancestor of humans and chimpanzees lived.

The Importance of Schöningen to the Story of Human Evolution in Europe

A lake site in northern Germany, near Schöningen, has lifted much of the veil of how advanced Homo heidelbergensis was during the later Lower Palaeolithic.  As Heritage Daily reports:

The excavations in the open-cast coal mine in Schöningen running from 1994 until today show that we have long underestimated the cultural capacities of Homo heidelbergensis. Schöningen is a key site for documenting both a high resolution record of past climatic change and how hominins lived in northern Europe during the Ice Age. Since 2008 Professor Nicholas Conard and Dr. Jordi Serangeli of the University of Tübingen have led the excavations with a major international research team in close cooperation with the Cultural Heritage Office of Lower Saxony.

the Journal of Human Evolution is making available for a time, all of the papers of a special issue on the site. That is how important it is. That link is here. 

What has been discovered, since the opening of the excavations, is that Homo heidelbergensis created advanced bone and stone implements, engaged in complex hunting behaviors and exhibited behaviors consistent with a high level of “planning depth.”  Further, they appear to have lived in a society with divisions of labor and a highly advanced communication system.

This has been referred to by the authors of one of the papers as “paradigm shifts in human evolution” and appears to represent, at least at this site and at this time period, a radical change in the way that humans were dealing with their surroundings.  In other words, at around 300,000 years ago, we seem to have the roots of modern human behavior, in Europe.  How much earlier this behavior actually shows up is, at the moment, anybody's guess.

Human Evolution in Two Minutes

I missed this when it came out.  The Indian Express has a link to a video done By Yale University Press by John Gurche, the same artist who did the Tower of Time, a wonderful mural that adorned the halls of the Natural History Museum, in Washington D.C. for years.

This video shows human evolutionary change as a morphing set of images.  Here it is.

Here's Irony For Ya...

A study has found that residents of South Africa, historically the hotbed of human evolutionary studies, have a poorer understanding of human evolution than their neighbors.  Jacaranda FM reports:

The study, published in the South African Journal of Science this month, used responses from visitors to the Cradle of Human Kind World Heritage Site near Johannesburg. “South Africans were less likely to accept human evolution than their international counterparts,” the article said. “The survey I did was mainly of adults who would never have learned of evolution at school,” said author of the study, Professor Anthony Lelliott from Wits University in Johannesburg. The study surveyed more than 800 visitors and assessed their understanding of human evolution and the concept of “cradle”. The article explained that 60 percent of the people who rejected evolution used a religious foundation as the reason.

I guess that in a rural setting, most of the people living in South Africa would not encounter this information or understand its true significance. Still, the entire region has been at the forefront of this research for decades, and yet most people still reject it. The hold of creationism is strong, it seems, no matter where you go.