Tag: neanderthals/hominids

Answering Scientific Questions on Neanderthal-Human Interbreeding

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By Fazale Rana – August 5, 2020

So don’t ask me no questions
And I won’t tell you no lies
And don’t ask me about my business
And I won’t tell you good-bye

“Don’t Ask Me No Questions”

—Ronnie Van Zandt and Gary Robert Rossington

One of my favorite rock bands of all time is Lynyrd Skynyrd. (That’s right…Skynyrd, baby!) I know their musical catalog forward and backwards. I don’t know if it is a good thing or not, but I am conversant with the history of most of the songs recorded by the band’s original lineup.

“Don’t Ask Me No Questions” was the first single released from their second studio album, Second Helping. The album also included “Sweet Home Alabama.” When juxtaposed with the success of “Sweet Home Alabama,” it’s ironic that “Don’t Ask Me No Questions” never even broke the charts.

An admonition to family and friends not to pry into their personal affairs, this song describes the exhaustion the band members felt after spending months on tour. All they want is peace and respite when they return home. Instead, they find themselves continuously confronted by unrelenting and inappropriate questions about the rock ‘n’ roll lifestyle.

As a Christian apologist, people ask me questions all the time. Yet, rarely do I find the questions annoying and inappropriate. I am happy to do my best to answer most of the questions asked of me—even the snarky ones posed by internet trolls. As of late, one topic that comes up often is interbreeding between modern humans and Neanderthals:

  • Is it true that modern humans and Neanderthals interbred?
  • If interbreeding took place, what does that mean for the credibility of the biblical account of human origins?
  • Did the children resulting from these interbreeding events have a soul? Did they bear the image of God?

Recently, an international team of investigators looking to catalog Neanderthal genetic contributions, surveyed a large sampling of Icelander genomes. This work generated new and unexpected insights about interbreeding between hominins and modern humans.1

No lie.

It came as little surprise to me when the headlines announcing this discovery triggered another round of questions about interbreeding between modern humans and Neanderthals. I will address the first two questions above in this article and the third one in a future post.

RTB’s Human Origins Model in 2005

To tell the truth, for a number of years I resisted the idea that modern humans interbred with Neanderthals and Denisovans. When Hugh Ross and I published the first edition of our book, Who Was Adam? (2005), there was no real evidence that modern humans and Neanderthals interbred. We took this absence of evidence as support for the RTB human origins model.

According to our model, Neanderthals have no evolutionary connection to modern humans. The RTB model posits that the hominins, such as Neanderthals and Denisovans, were creatures made by God that existed for a time and went extinct. These creatures had intelligence and emotional capacity (like most mammals), which enabled them to establish a culture. However, unlike modern humans, these creatures lacked the image of God. Accordingly, they were cognitively inferior to modern humans. In this sense, the RTB human origins model regards the hominins in the same vein as the great apes: intelligent, fascinating creatures in their own right that share some biological and behavioral attributes with modern humans (reflecting common design). Yet, no one would confuse a great ape and a modern human because of key biological distinctions and, more importantly, because of profound cognitive and behavioral differences.

When we initially proposed our model, we predicted that the biological differences between modern humans and Neanderthals would have made interbreeding unlikely. And if they did interbreed, then these differences would have prohibited the production of viable, fertile offspring.

Did Humans and Neanderthals Interbreed?

In 2010, researchers produced a rough draft sequence of the Neanderthal genome and compared it to modern human genomes. They discovered a closer statistical association of the Neanderthal genome with those from European and Asian people groups than with genomes from African people groups.2 The researchers maintained that this effect could be readily explained if a limited number of interbreeding events took place between humans and Neanderthals in the eastern portion of the Middle East, roughly 45,000 to 80,000 years ago, just as humans began to migrate around the world. This would explain why non-African populations display what appears to be a 1 to 4 percent genetic contribution from Neanderthals while African people groups have no contribution whatsoever.

At that time, I wasn’t entirely convinced that modern humans and Neanderthals interbred because there were other ways to explain the statistical association. Additionally, studies of Neanderthal genomes indicate that these hominins lived in small insular groups. At that time, I argued that the low population densities of Neanderthals would have greatly reduced the likelihood of encounters with modern humans migrating in small populations. It seemed to me that it was unlikely that interbreeding occurred.

Other studies demonstrated that Neanderthals most likely were extinct before modern humans made their way into Europe. Once again, I argued that the earlier extinction of Neanderthals makes it impossible for them to have interbred with humans in Europe. Extinction also raises questions about whether the two species interbred at all.

The Case for Interbreeding

Despite these concerns, in the last few years I have become largely convinced that modern humans and Neanderthals interbred. Studies such as the one cataloging the Neanderthal contribution to the genomes of Icelanders leave me little choice in the matter.

Thanks to the deCODE project, the genome sequences for nearly half the Icelandic population have been determined. An international team of collaborators made use of this data set, analyzing over 27,500 Icelander genomes for Neanderthal contribution using a newly developed algorithm. They detected over 14.4 million fragments of Neanderthal DNA in their data set. Of these, 112,709 were unique sequences that collectively constituted 48 percent of the Neanderthal genome.

This finding has important implications. Even though individual Icelanders have about a 1 to 4 percent Neanderthal contribution to their genomes, the precise contribution differs from person to person. And when these individual contributions are combined it yields Neanderthal DNA sequences that cover nearly 50 percent of the Neanderthal genome. This finding aligns with previous studies which demonstrate that, collectively, across the human population Neanderthal sequences are distributed throughout 20 percent of the human genome. And 40 percent of the Neanderthal genome can be reconstructed from Neanderthal sequences found in a sampling of Eurasian genomes.3

Adding to this evidence for interbreeding are studies that characterized ancient DNA recovered from several modern human fossil remains unearthed in Europe, dating between about 35,000 and 45,000 years in age. The genomes of these ancient modern humans contain much longer stretches of Neanderthal DNA than what’s found in contemporary modern humans, which is exactly what would be expected if modern humans interbred with these hominins.4

As I see it, interbreeding is the only way to make sense of these results.

Are Humans and Neanderthals the Same Species?

Because the biological species concept (BSC) defines a species as an interbreeding population, some people argue that modern humans and Neanderthals must belong to the same species. This perspective is common among young-earth creationists who see Neanderthals as a subset of humanity.

This argument fails to take into account the limitations of the BSC, one being the phenomenon of hybridization. Mammals that belong to separate species have been known to interbreed and produce viable—even fertile—offspring called hybrids. For example, lions and tigers in captivity have interbred successfully—yet both parent animals remain considered separate species. I would argue that the concept of hybridization applies to the interbreeding that took place between modern humans and Neanderthals.

Even though it appears that modern humans and Neanderthals interbred, other lines of evidence indicate that these two hominins were distinct species. Significant anatomical differences exist between the two. The most profound difference is skull anatomy and, consequently, brain structure

blog__inline--answering-scientific-questions-on-neanderthal-human-interbreeding-part-1Anatomical Differences between Human and
Neanderthal Skulls. Image credit: Wikipedia.

Additionally, Neanderthals possessed a hyper-polar body design, consisting of a stout, barrel-shaped body with shortened limbs to help with heat retention. Neanderthals and modern humans display significant developmental differences as well. Neanderthals, for example, spent a minimal time in adolescence compared to modern humans. The two hominins also exhibit significant genetic differences (which includes differences in gene expression patterns), most notably for genes that play a role in cognition and cognitive development. Most critically, modern humans and Neanderthals display significant behavioral differences that stem from substantial differences in cognitive capacity.

Along these lines, it is important to note that researchers believe that the resulting human-Neanderthal hybrids lacked fecundity.5 As geneticist David Reich notes, “Modern humans and Neanderthals were at the edge of biological compatibility.”6

In other words, even though modern humans and Neanderthals interbred, they displayed sufficient biological differences that are extensive enough to justify classing the two as distinct species, just as the RTB model predicts. The extensive behavioral differences also validate the view that modern humans are exceptional and unique in ways that align with the image of God—again, in accord with RTB model predictions.

Is the RTB Human Origins Model Invalid?

It is safe to say that most paleoanthropologists view modern humans and Neanderthals as distinct species (or at least distinct populations that were isolated from one another for over 500,000 to 600,000 years). From an evolutionary perspective, modern humans and Neanderthals share a common evolutionary ancestor, perhaps Homo heidelbergensis, and arose as separate species as the two lineages diverged from this ancestral population. In the evolutionary framework, the capacity of Neanderthals and modern humans to interbreed reflects their shared evolutionary heritage. For this reason, some critics have pointed to the interbreeding between modern humans and other hominins as a devastating blow to the RTB model and as clear-cut evidence for human evolution.

In light of this concern, it is important to recognize that the RTB human origins model readily accommodates the evidence for interbreeding between modern humans and Neanderthals. Instead of reflecting a shared evolutionary ancestry, within a creation model framework, the capacity for interbreeding is a consequence of the biological designs shared by modern humans and Neanderthals.

The RTB model’s stance that shared biological features represent common design taps into a rich tradition within the history of biology. Prior to Charles Darwin, life scientists such as the preeminent biologist Sir Richard Owen, routinely viewed homologous systems as manifestations of archetypal designs that resided in the Mind of the First Cause. The RTB human origins model co-opts Owen’s ideas and applies them to the biological features modern humans share with other creatures, including the hominins.

Without question, the discovery that modern humans interbred with other hominins, stands as a failed prediction of the initial version of the RTB human origins model. However, this discovery can be accommodated by revising the model–as is often done in science. Of course, this leads to the next set of questions.

  • Is there biblical warrant to think that modern humans interbred with other creatures?
  • Did the modern human-Neanderthal hybrid have a soul? Did it bear God’s image?

I will take on these questions in the next article. And I am telling you no lie.

Resources

Biological Differences between Humans and Neanderthals

Archetype Biology

Endnotes
  1. Laurits Skov et al., “The Nature of Neanderthal Introgression Revealed by 27,566 Icelandic Genomes,” Nature (published online April 22, 2020), doi:10.1038/s49586-020-2225-9.
  2. Fazale Rana with Hugh Ross, Who Was Adam? A Creation Model Approach to the Origin of Humanity, 10-Year Update (Covina, CA: RTB Press, 2015), 301–12.
  3. Sriram Sankararaman et al., “The Genomic Landscape of Neanderthal Ancestry in Present-Day Humans,” Nature 507 (2014): 354–57, doi:10.1038/nature12961; Benjamin Vernot and Joshua M. Akey, “Resurrecting Surviving Neandertal Lineages from Modern Human Genomes,” Science 343 (2014): 1017–21, doi: 10.1126/science.1245938.
  4. Rana with Ross, Who Was Adam?, 304–5.
  5. Sankararaman et al., “Genomic Landscape,” 354–57, Vernot and Akey, “Resurrecting Surviving Neandertal Lineages,” 1017–21.
  6. Ewen Callaway, “Modern Human Genomes Reveal Our Inner Neanderthal,” Nature News (January 29, 2014), https://www.nature.com/news/modern-human-genomes-reveal-our-inner-neanderthal-1.14615.

Reprinted with permission by the author

Original article at:
https://reasons.org/explore/blogs/the-cells-design

New Genetic Evidence Affirms Human Uniqueness

By Fazale Rana – March 4, 2020

It’s a remarkable discovery—and a bit gruesome, too.

It is worth learning a bit about some of its unseemly details because this find may have far-reaching implications that shed light on our origins as a species.

In 2018, a group of locals discovered the remains of a two-year-old male puppy in the frozen mud (permafrost) in the eastern part of Siberia. The remains date to 18,000 years in age. Remarkably, the skeleton, teeth, head, fur, lashes, and whiskers of the specimen are still intact.

Of Dogs and People

The Russian scientists studying this find (affectionately dubbed Dogor) are excited by the discovery. They think Dogor can shed light on the domestication of wolves into dogs. Biologists believe that this transition occurred around 15,000 years ago. Is Dogor a wolf? A dog? Or a transitional form? To answer these questions, the researchers have isolated DNA from one of Dogor’s ribs, which they think will provide them with genetic clues about Dogor’s identity—and clues concerning the domestication process.

Biologists study the domestication of animals because this process played a role in helping to establish human civilization. But biologists are also interested in animal domestication for another reason. They think this insight will tell us something about our identity as human beings.

In fact, in a separate study, a team of researchers from the University of Milan in Italy used insights about the genetic changes associated with the domestication of dogs, cats, sheep, and cattle to identify genetic features that make human beings (modern humans) stand apart from Neanderthals and Denisovans.1 They conclude that modern humans share some of the same genetic characteristics as domesticated animals, accounting for our unique and distinct facial features (compared to other hominins). They also conclude that our high level of cooperativeness and lack of aggression can be explained by these same genetic factors.

This work in comparative genomics demonstrates that significant anatomical and behavioral differences exist between humans and hominins, supporting the concept of human exceptionalism. Though the University of Milan researchers carried out their work from an evolutionary perspective, I believe their insights can be recast as scientific evidence for the biblical conception of human nature; namely, creatures uniquely made in God’s image.

Biological Changes that Led to Animal Domestication

Biologists believe that during the domestication process, many of the same biological changes took place in dogs, cats, sheep, and cattle. For example, they think that during domestication, mild deficits in neural crest cells resulted. In other words, once animals are domesticated, they produce fewer, less active neural crest cells. These stem cells play a role in neural development; thus, neural crest cell defects tend to make animals friendlier and less aggressive. This deficit also impacts physical features, yielding smaller skulls and teeth, floppy ears, and shorter, curlier tails.

Life scientists studying the domestication process have identified several genes of interest. One of these is BAZ1B. This gene plays a role in the maintenance of neural crest cells and controls their migration during embryological development. Presumably, changes in the expression of BAZ1B played a role in the domestication process.

Neural Crest Deficits and Williams Syndrome

As it turns out, there are two genetic disorders in modern humans that involve neural crest cells: Williams-Beuren syndrome (also called Williams syndrome) and Williams-Beuren region duplication syndrome. These genetic disorders involve the deletion or duplication, respectively, of a region of chromosome 7 (7q11.23). This chromosomal region harbors 28 genes. Craniofacial defects and altered cognitive and behavioral traits characterize these disorders. Specifically, people with these syndromes have cognitive limitations, smaller skulls, and elf-like faces, and they display excessive friendliness.

Among the 28 genes impacted by the two disorders is the human version of BAZ1B. This gene codes for a type of protein called a transcription factor. (Transcription factors play a role in regulating gene expression.)

The Role of BAZ1B in Neural Crest Cell Biology

To gain insight into the role BAZ1B plays in neural crest cell biology, the European research team developed induced pluripotent stem cell lines from (1) four patients with Williams syndrome, (2) three patients with Williams-Beuren region duplication syndrome, and (3) four people without either disorder. Then, they coaxed these cells in the laboratory to develop into neural crest cells.

Using a technique called RNA interference, they down-regulated BAZ1B in all three types of neural crest cells. By doing this, the researchers learned that changes in the expression of this gene altered the migration rates of the neural crest cells. Specifically, they discovered that neural crest cells developed from patients with Williams-Beuren region duplication syndrome migrated more slowly than control cells (generated from test subjects without either syndrome) and neural crest cells derived from patients with Williams syndrome migrated more rapidly than control cells.

The discovery that the BAZ1B gene influences neural crest cell migration is significant because these cells have to migrate to precise locations in the developing embryo to give rise to distinct cell types and tissues, including those that form craniofacial features.

Because BAZ1B encodes for a transcription factor, when its expression is altered, it alters the expression of genes under its control. The team discovered that 448 genes were impacted by down-regulating BAZ1B. They learned that many of these impacted genes play a role in craniofacial development. By querying databases of genes that correlate with genetic disorders, researchers also learned that, when defective, some of the impacted genes are known to cause disorders that involve altered facial development and intellectual disabilities.

Lastly, the researchers determined that the BAZ1B protein (again, a transcription factor) targets genes that influence dendrite and axon development (which are structures found in neurons that play a role in transmissions between nerve cells).

BAZ1B Gene Expression in Modern and Archaic Humans

With these findings in place, the researchers wondered if differences in BAZ1B gene expression could account for anatomical and cognitive differences between modern humans and archaic humans—hominins such as Neanderthals and Denisovans. To carry out this query, the researchers compared the genomes of modern humans to Neanderthals and Denisovans, paying close attention to DNA sequence differences in genes under the influence of BAZ1B.

This comparison uncovered differences in the regulatory region of genes targeted by the BAZ1B transcription factor, including genes that control neural crest cell activities and craniofacial anatomy. In other words, the researchers discovered significant genetic differences in gene expression among modern humans and Neanderthals and Denisovans. And these differences strongly suggest that anatomical and cognitive differences existed between modern humans and Neanderthals and Denisovans.

Did Humans Domesticate Themselves?

The researchers interpret their findings as evidence for the self-domestication hypothesis—the idea that we domesticated ourselves after the evolutionary lineage that led to modern humans split from the Neanderthal/Denisovan line (around 600,000 years ago). In other words, just as modern humans domesticated dogs, cats, cattle, and sheep, we domesticated ourselves, leading to changes in our anatomical features that parallel changes (such as friendlier faces) in the features of animals we domesticated. Along with these anatomical changes, our self-domestication led to the high levels of cooperativeness characteristic of modern humans.

On one hand, this is an interesting account that does seem to have some experimental support. But on the other, it is hard to escape the feeling that the idea of self-domestication as the explanation for the origin of modern humans is little more than an evolutionary just-so story.

It is worth noting that some evolutionary biologists find this account unconvincing. One is William Tecumseh Fitch III—an evolutionary biologist at the University of Vienna. He is skeptical of the precise parallels between animal domestication and human self-domestication. He states, “These are processes with both similarities and differences. I also don’t think that mutations in one or a few genes will ever make a good model for the many, many genes involved in domestication.”2

Adding to this skepticism is the fact that nobody has anything beyond a speculative explanation for why humans would domesticate themselves in the first place.

Genetic Differences Support the Idea of Human Exceptionalism

Regardless of the mechanism that produced the genetic differences between modern and archaic humans, this work can be enlisted in support of human uniqueness and exceptionalism.

Though the claim of human exceptionalism is controversial, a minority of scientists operating within the scientific mainstream embrace the idea that modern humans stand apart from all other extant and extinct creatures, including Neanderthals and Denisovans. These anthropologists argue that the following suite of capacities uniquely possessed by modern humans accounts for our exceptional nature:

  • symbolism
  • open-ended generative capacity
  • theory of mind
  • capacity to form complex social systems

As human beings, we effortlessly represent the world with discrete symbols. We denote abstract concepts with symbols. And our ability to represent the world symbolically has interesting consequences when coupled with our abilities to combine and recombine those symbols in a countless number of ways to create alternate possibilities. Our capacity for symbolism manifests in the form of language, art, music, and even body ornamentation. And we desire to communicate the scenarios we construct in our minds with other human beings.

But there is more to our interactions with other human beings than a desire to communicate. We want to link our minds together. And we can do this because we possess a theory of mind. In other words, we recognize that other people have minds just like ours, allowing us to understand what others are thinking and feeling. We also have the brain capacity to organize people we meet and know into hierarchical categories, allowing us to form and engage in complex social networks. Forming these relationships requires friendliness and cooperativeness.

In effect, these qualities could be viewed as scientific descriptors of the image of God, if one adopts a resemblance view for the image of God.

This study demonstrates that, at a genetic level, modern humans appear to be uniquely designed to be friendlier, more cooperative, and less aggressive than other hominins—in part accounting for our capacity to form complex hierarchical social structures.

To put it differently, the unique capability of modern humans to form complex, social hierarchies no longer needs to be inferred from the fossil and archaeological records. It has been robustly established by comparative genomics in combination with laboratory studies.

A Creation Model Perspective on Human Origins

This study not only supports human exceptionalism but also affirms RTB’s human origins model.

RTB’s biblical creation model identifies hominins such as Neanderthals and the Denisovans as animals created by God. These extraordinary creatures possessed enough intelligence to assemble crude tools and even adopt some level of “culture.” However, the RTB model maintains that these hominids were not spiritual creatures. They were not made in God’s image. RTB’s model reserves this status exclusively for Adam and Eve and their descendants (modern humans).

Our model predicts many biological similarities will be found between the hominins and modern humans, but so too will significant differences. The greatest distinction will be observed in cognitive capacity, behavioral patterns, technological development, and culture—especially artistic and religious expression.

The results of this study fulfill these two predictions. Or, to put it another way, the RTB model’s interpretation of the hominins and their relationship to modern humans aligns with “mainstream” science.

But what about the similarities between the genetic fingerprint of modern humans and the genetic changes responsible for animal domestication that involve BAZ1B and genes under its influence?

Instead of viewing these features as traits that emerged through parallel and independent evolutionary histories, the RTB human origins model regards the shared traits as reflecting shared designs. In this case, through the process of domestication, modern humans stumbled upon the means (breeding through artificial selection) to effect genetic changes in wild animals that resemble some of the designed features of our genome that contribute to our unique and exceptional capacity for cooperation and friendliness.

It is true: studying the domestication process does, indeed, tell us something exceptionally important about who we are.

Resources

Endnotes
  1. Matteo Zanella et al., “Dosage Analysis of the 7q11.23 Williams Region Identifies BAZ1B as a Major Human Gene Patterning the Modern Human Face and Underlying Self-Domestication,” Science Advances 5, no. 12 (December 4, 2019): eaaw7908, doi:10.1126/sciadv.aaw7908.
  2. Michael Price, “Early Humans Domesticated Themselves, New Genetic Evidence Suggests,” Science (December 4, 2019), doi:10.1126/science.aba4534.

Reprinted with permission by the author

Original article at:

https://reasons.org/explore/blogs/the-cells-design

Ancient DNA Indicates Modern Humans Are One-of-a-Kind

By Fazale Rana – February 19, 2020

The wonderful thing about tiggers
Is tiggers are wonderful things!
Their tops are made out of rubber
Their bottoms are made out of springs!
They’re bouncy, trouncy, flouncy, pouncy
Fun, fun, fun, fun, fun!
But the most wonderful thing about tiggers is
I’m the only one!1

With eight grandchildren and counting (number nine will be born toward the end of February), I have become reacquainted with children’s stories. Some of the stories my grandchildren want to hear are new, but many of them are classics. It is fun to see my grandchildren experiencing the same stories and characters I enjoyed as a little kid.

Perhaps my favorite children’s book of all time is A. A. Milne’s (1882–1956) Winnie-the-Pooh. And of all the characters that populated Pooh Corner, my favorite character is the ineffable Tigger—the self-declared one-of-a-kind.

blog__inline--ancient-dna-indicates-modern-humans-1
A. A. Milne. Credit: Wikipedia

For many people (such as me), human beings are like Tigger. We are one-of-a-kind among creation. As a Christian, I take the view that we are unique and exceptional because we alone have been created in God’s image.

For many others, the Christian perspective on human nature is unpopular and offensive. Who are we to claim some type of special status? They insist that humans aren’t truly unique and exceptional. We are not fundamentally different from other creatures. If anything, we differ only in degree, not kind. Naturalists and others assert that there is no evidence that human beings bear God’s image. In fact, some would go so far as to claim that creatures such as Neanderthals were quite a bit like us. They maintain that these hominins were “exceptional,” just like us. Accordingly, if we are one-of-a-kind it is because, like Tigger, we have arrogantly declared ourselves to be so, when in reality we are no different from any of the other characters who make their home at Pooh Corner.

Despite this pervasive and popular challenge to human exceptionalism (and the image-of-God concept), there is mounting evidence that human beings stand apart from all extant creatures (such as the great apes) and extinct creatures (such as Neanderthals). This growing evidence can be marshaled to make a scientific case that as human beings we, indeed, are image bearers.

As a case in point, many archeological studies affirm human uniqueness and exceptionalism. (See the Resources section for a sampling of some of this work.) These studies indicate that human beings alone possess a suite of characteristics that distinguish us from all other hominins. I regard these qualities as scientific descriptors of the image of God:

  • Capacity for symbolism
  • Ability for open-ended manipulation of symbols
  • Theory of mind
  • Capacity to form complex, hierarchical social structures

Other studies have identified key differences between the brains of modern humans and Neanderthals. (For a sample of this evidence see the Resources section.) One key difference relates to skull shape. Neanderthals (and other hominins) possessed an elongated skull. In contradistinction, our skull shape is globular. The globularity allows for the expansion of the parietal lobe. This is significant because an expanded parietal lobe explains a number of unique human characteristics:

  • Perception of stimuli
  • Sensorimotor transformation (which plays a role in planning)
  • Visuospatial integration (which provides hand-eye coordination)
  • Imagery
  • Self-awareness
  • Working and long-term memory

Again, I connect these scientific qualities to the image of God.

Now, two recent studies add to the case for human exceptionalism. They involve genetic comparisons of modern humans with both Neanderthals and Denisovans. Through the recovery and sequencing of ancient DNA, we have high quality genomes for these hominins that we can analyze and compare to the genomes of modern humans.

While the DNA sequences of protein-coding genes in modern human genomes and the genomes of these two extant hominins is quite similar, both studies demonstrate that the gene expression is dramatically different. That difference accounts for anatomical differences between humans and these two hominins and suggests that significant cognitive differences exist as well.

Differences in Gene Regulation

To characterize gene expression patterns in Neanderthals and Denisovans and compare them to modern humans, researchers from Vanderbilt University (VU) used statistical methods to develop a mathematical model that would predict gene expression profiles from the DNA sequences of genomes.2 They built their model using DNA sequences and gene expression data (measured from RNA produced by transcription) for a set of human genomes. To ensure that their model could be used to assess gene expression for Neanderthals and Denisovans, the researchers paid close attention to the gene expression pattern for genes in the human genome that were introduced when modern humans and Neanderthals presumably interbred and compared their expression to human genes that were not of Neanderthal origin.

blog__inline--ancient-dna-indicates-modern-humans-2The Process of Gene
Expression.
Credit: Shutterstock

With their model in hand, the researchers analyzed the expression profile for nearly 17,000 genes from the Altai Neanderthal. Their model predicts that 766 genes in the Neanderthal genome had a different expression profile than the corresponding genes in modern humans. As it turns out, the differentially expressed genes in the Neanderthal genomes failed to be incorporated into the human genome after interbreeding took place, suggesting to the researchers that these genes are responsible for key anatomical and physiological differences between modern humans and Neanderthals.

The VU investigators determined that these 766 deferentially expressed genes play roles in reproduction, forming skeletal structures, and the functioning of cardiovascular and immune systems.

Then, the researchers expanded their analysis to include two other Neanderthal genomes (from the Vindija and Croatian specimens) and the Denisovan genome. The researchers learned that the gene expression profiles of the three Neanderthal genomes were more similar to one another than they were to either the gene expression patterns of modern human and Denisovan genomes.

This study clearly demonstrates that significant differences existed in the regulation of gene expression in modern humans, Neanderthals, and Denisovans and that these differences account for biological distinctives between the three hominin species.

Differences in DNA Methylation

In another study, researchers from Israel compared gene expression profiles in modern human genomes with those from and Neanderthals and Denisovans using a different technique. This method assesses DNA methylation.3 (Methylation of DNA downregulates gene expression, turning genes off.)

Methylation of DNA influences the degradation process for this biomolecule. Because of this influence, researchers can determine the DNA methylation pattern in ancient DNA by characterizing the damage to the DNA fragments isolated from fossil remains.

Using this technique, the researchers measured the methylation pattern for genomes of two Neanderthals (Altai and Vindija) and a Denisovan and compared these patterns with genomes recovered from the remains of three modern humans, dating to 45,000 years in age, 8,000 years in age, and 7,000 years in age, respectively. They discovered 588 genes in modern human genomes with a unique DNA methylation pattern, indicating that these genes are expressed differently in modern humans than in Neanderthals and Denisovans. Among the 588 genes, researchers discovered some that influence the structure of the pelvis, facial morphology, and the larynx.

The researchers think that differences in gene expression may explain the anatomical differences between modern humans and Neanderthals. They also think that this result indicates that Neanderthals lacked the capacity for speech.

What Is the Relationship between Modern Humans and Neanderthals?

These two genetic studies add to the extensive body of evidence from the fossil record, which indicates that Neanderthals are biologically distinct from modern humans. For a variety of reasons, some Christian apologists and Intelligent Design proponents classify Neanderthals and modern humans into a single group, arguing that the two are equivalent. But these two studies comparing gene regulation profiles make it difficult to maintain that perspective.

Modern Humans, Neanderthals, and the RTB Human Origins Model

RTB’s human origins model regards Neanderthals (and other hominins) as creatures made by God, without any evolutionary connection to modern humans. These extraordinary creatures walked erect and possessed some level of intelligence, which allowed them to cobble together tools and even adopt some level of “culture.” However, our model maintains that the hominins were not spiritual beings made in God’s image. RTB’s model reserves this status exclusively for modern humans.

Based on our view, we predict that biological similarities will exist among the hominins and modern humans to varying degrees. In this regard, we consider the biological similarities to reflect shared designs, not a shared evolutionary ancestry. We also expect biological differences because, according to our model, the hominins would belong to different biological groups from modern humans.

We also predict that significant cognitive differences would exist between modern humans and the other hominins. These differences would be reflected in brain anatomy and behavior (inferred from the archeological record). According to our model, these differences reflect the absence of God’s image in the hominins.

The results of these two studies affirm both sets of predictions that flow from the RTB human origins model. The differences in gene regulation between modern human and Neanderthals is precisely what our model predicts. These differences seem to account for the observed anatomical differences between Neanderthals and modern humans observed from fossil remains.

The difference in the regulation of genes affecting the larynx is also significant for our model and the idea of human exceptionalism. One of the controversies surrounding Neanderthals relates to their capacity for speech and language. Yet, it is difficult to ascertain from fossil remains if Neanderthals had the anatomical structures needed for the vocalization range required for speech. The differences in the expression profiles for genes that control the development and structure of the larynx in modern humans and Neanderthals suggests that Neanderthals lacked the capacity for speech. This result dovetails nicely with the differences in modern human and Neanderthal brain structure, which suggest that Neanderthals also lacked the neural capacity for language and speech. And, of course, it is significant that there is no conclusive evidence for Neanderthal symbolism in the archeological record.

With these two innovative genetic studies, the scientific support for human exceptionalism continues to mount. And the wonderful thing about this insight is that it supports the notion that as human beings we are the only ones who bear God’s image and can form a relationship with our Creator.

Resources

Behavioral Differences between Humans and Neanderthals

Biological Differences between Humans and Neanderthals

Endnotes
  1. Richard M. Sherman and Robert B. Sherman, composers, “The Wonderful Thing about Tiggers” (song), released December 1968.
  2. Laura L. Colbran et al., “Inferred Divergent Gene Regulation in Archaic Hominins Reveals Potential Phenotypic Differences,” Nature Evolution and Ecology 3 (November 2019): 1598-606, doi:10.1038/s41559-019-0996-x.
  3. David Gokhman et al., “Reconstructing the DNA Methylation Maps of the Neandertal and the Denisovan,” Science 344, no. 6183 (May 2, 2014): 523–27, doi:1126/science.1250368; David Gokhman et al., “Extensive Regulatory Changes in Genes Affecting Vocal and Facial Anatomy Separate Modern from Archaic Humans,” bioRxiv, preprint (October 2017), doi:10.1101/106955.

Reprinted with permission by the author

Original article at:

https://reasons.org/explore/blogs/the-cells-design

Glue Production Is Not Evidence for Neanderthal Exceptionalism

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By Fazale Rana – November 6, 2019

Football players aren’t dumb jocks—though they often have that reputation. Football is a physically demanding sport that requires strength, toughness, agility, and speed. But it is also an intellectually demanding game.

Mastering a playbook, understanding which plays work best for the various in-game scenarios, recognizing defenses and offenses, and adjusting on the fly require hours of study and preparation. Football really is a thinking person’s game.

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Figure 1: Quarterback Calling an Audible at the Line of Scrimmage. Image Credit: Shutterstock

Some anthropologists view Neanderthals in the same way that many people view football players: as the “dumb jock” version of a hominin, a creature cognitively inferior to modern humans. Yet, other anthropologists dispute this characterization, arguing that it is undeserved. Instead, they claim that Neanderthals had cognitive capabilities on par with modern humans.

In support of their claim, these scientists point to finds in the archaeological record that seemingly suggest these hominins were exceptional, just like modern humans. As a case in point, archaeologists have unearthed evidence for tar production at a site in Italy that dates to around 200,000 years in age. They interpret this discovery as evidence that Neanderthals were using tar as glue for hafting (fixing) flint spearheads to wooden spear shafts.1 Archaeologists have also unearthed spearheads with tar residue from two sites in Germany, one dating to 120,000 years in age and the other between 40,000 to 80,000 years.2 Because these dates precede the arrival of modern humans into Europe, anthropologists assume the tar at these sites was deliberately produced and used by Neanderthals.

Adhesives as a Signature for Superior Cognition

Anthropologists consider the development of adhesives as a transformative technology. These materials would have provided the first humans the means to construct new types of complex devices and combine different types of materials (composites) into new technologies. Because of this new proficiency, anthropologists consider the production and use of adhesives to be diagnostic of advanced cognitive capabilities such as forward planning, abstraction, and understanding of materials.

Production of adhesives from natural sources, even by the earliest modern humans, appears to have been a complex operation that required precise temperature control and the use of earthen mounds, or ceramic or metal kilns. In addition, birch bark needed to be heated in the absence of oxygen. Because the first large-scale production of adhesives usually centered around the dry distillation of birch and pine barks to produce tar and pitch, researchers have assumed that this technique is the only way to generate tar.

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Figure 2: Tar Produced from Birch Bark. Image credit: Wikipedia

So, if Neanderthals were using tar as an adhesive, the reasoning goes, they must have been pretty impressive creatures.

In the summer of 2017 researchers from the University of Leiden published work that seemed to support this view.3 To address the question of how Neanderthals may have produced adhesives, these investigators conducted a series of experiments. They sought to learn how Neanderthals used the resources most reasonably available to them to obtain tar from birch bark through dry distillation.

By studying a variety of methods for dry distillation of tar from birch in a laboratory setting, the research team concluded that Neanderthals could have produced tar from birch bark if they had used methods that were simple enough that they wouldn’t require precise temperature control during the distillation. Still, these methods are complex enough that the researchers concluded that for Neanderthals to pull off this feat, they must have had advanced cognitive abilities similar to those of modern humans.

Is Adhesive Production and Use Evidence for Neanderthal Exceptionalism?

At the time this work was reported, I challenged this conclusion by noting that the simplicity of these production methods argued against advanced cognitive abilities in Neanderthals, not for them.

Recent work by researchers from Germany affirms my skepticism. Their research challenges the view that adhesive production and use constitutes evidence for human exceptionalism.4 The team wondered if a simpler way to produce tar—even simpler than the methods identified by the research team from the University of Leiden— exists. They also wondered if it was possible to produce tar in the presence of oxygen.

From their work, they discovered that burning birch bark (or branches from a birch tree with the bark still attached) adjacent to a rock with a vertical or subvertical surface is a way to collect tar, which naturally deposits on the rock surface as the bark burns. In other words, tar can be produced accidentally, instead of deliberately. And once produced, it can be scraped from the rock surface.

Using analytical techniques (gas chromatography coupled to mass spectrometry) to characterize the chemical makeup of the tar produced by this simple method, the research team showed that it is comparable to the chemical composition of tars produced by sophisticated dry distillation methods under anaerobic conditions. Because of the simplicity of this method, the research team thinks that collecting tar deposits from burning birch on rocks is the most likely way that Neanderthals produced tar, if they intentionally produced it at all.

According to the research team, “The identification of birch tar at archaeological sites can no longer be considered as a proxy for human (complex, cultural) behavior as previously assumed. In other words, our finding changes textbook thinking about what tar production is a smoking gun of.”5

One other point merits consideration: A growing body of evidence indicates that Neanderthals did not master fire, but rather used it opportunistically. In other words, these creatures could not create fire, but did harvest wildfires. Evidence demonstrates that there were vast periods of time during Neanderthals’ tenure in Europe when wildfires were rare because of cold climatic conditions. During these periods, Neanderthals didn’t use fire.

Because fire is central to the dry distillation methods, for a significant portion of their time on Earth Neanderthals would have been unable to extract tar and use it for hafting. Perhaps this factor explains why recovery of tar from Neanderthal sites is so rare. And could it be that Neanderthals were not intentionally producing tar? Instead, did tar just happen to collect on rock surfaces as a consequence of burning birch branches when these creatures were able to harvest fire?

What Difference Does It Make?

One of the most important ideas taught in Scripture is that human beings uniquely bear God’s image. As such, every human being has immeasurable worth and value. And because we bear God’s image, we can enter into a relationship with our Maker.

However, if Neanderthals possessed advanced cognitive ability just like that of modern humans, then it becomes difficult to maintain the view that modern humans are unique and exceptional. If human beings aren’t exceptional, then it becomes a challenge to defend the idea that human beings are made in God’s image.

Yet, claims that Neanderthals are cognitive equals to modern humans fail to withstand scientific scrutiny, time and time again, as this latest study demonstrates. It is unlikely that any of us will see a Neanderthal run onto the football field anytime soon.

Resources

Neanderthals Did Not Master Fire

Differences in Human and Neanderthal Brains

Endnotes
  1. Paul Peter Anthony Mazza et al., “A New Palaeolithic Discovery: Tar-Hafted Stone Tools in a European Mid-Pleistocene Bone-Bearing Bed,” Journal of Archaeological Science 33, no. 9 (September 2006): 1310–18, doi:10.1016/j.jas.2006.01.006.
  2. Johann Koller, Ursula Baumer, and Dietrich Mania, “High-Tech in the Middle Palaeolithic: Neandertal-Manufactured Pitch Identified,” European Journal of Archaeology 4, no. 3 (December 1, 2001): 385–97, doi:10.1179/eja.2001.4.3.385; Alfred F. Pawlik and Jürgen P. Thissen, “Hafted Armatures and Multi-Component Tool Design at the Micoquian Site of Inden-Altdorf, Germany,” Journal of Archaeological Science 38, no. 7 (July 2011): 1699–1708, doi:10.1016/j.jas.2011.03.001.
  3. P. R. B. Kozowyk et al., “Experimental Methods for the Palaeolithic Dry Distillation of Birch Bark: Implications for the Origin and Development of Neandertal Adhesive Technology,” Scientific Reports 7 (August 31, 2017): 8033, doi:10.1038/s41598-017-08106-7.
  4. Patrick Schmidt et al., “Birch Tar Production Does Not Prove Neanderthal Behavioral Complexity,” Proceedings of the National Academy of Sciences, USA 116, no. 36 (September 3, 2019): 17707–11, doi:10.1073/pnas.1911137116.
  5. Schmidt et al., “Birch Tar Production.”

Reprinted with permission by the author

Original article at:
https://reasons.org/explore/blogs/the-cells-design

Primate Thanatology and the Case for Human Exceptionalism

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By Fazale Rana – September 18, 2019

I will deliver this people from the power of the grave;
I will redeem them from death.
Where, O death, are your plagues?
Where, O grave, is your destruction?

—Hosea 13:14

It was the first time someone I knew died. I was in seventh grade. My classmate’s younger brother and two younger sisters perished in a fire that burned his family’s home to the ground. We lived in a small rural town in West Virginia at the time. Everyone knew each other and the impact of that tragedy reverberated throughout the community.

I was asked to be a pallbearer at the funeral. To this day, I remember watching my friend’s father with a cast on one arm and another on one of his legs, hobble up to each of the little caskets to touch them one last time as he sobbed uncontrollably right before we lifted and carried the caskets to the waiting hearses.

Death is part of life and our reaction to death is part of what makes us human. But, are humans unique in this regard?

Funerary Practices

Human responses to death include funerary practices—ceremonies that play an integral role in the final disposition of the body of the deceased.

Anthropologists who study human cultures see funerals as providing important scientific insight into human nature. These scientists define funerals as cultural rituals designed to honor, remember, and celebrate the life of those who have died. Funerals provide an opportunity for people to express grief, mourn loss, offer sympathy, and support the bereaved. Also, funerals often serve a religious purpose that includes (depending on the faith tradition) praying for the person who has died, helping his or her soul transition to the afterlife (or reincarnate).

Funerary Practices and Human Exceptionalism

For many anthropologists, human funerary practices are an expression of our capacities for:

  • symbolism
  • open-ended generative manipulation of symbols
  • theory of mind
  • complex, hierarchical social interactions

Though the idea of human exceptionalism is controversial within anthropology today, a growing minority of anthropologists argue that the combination of these qualities sets us apart from other creatures. They make us unique and exceptional.

As a Christian, I view this set of qualities as scientific descriptors of the image of God. That being the case, then, from my vantage point, human funerary practices (along with language, music, and art) are part of the body of evidence that we can marshal to make the case that human beings uniquely bear God’s image.

What about Neanderthals?

But are human beings really unique and exceptional?

Didn’t Neanderthals bury their dead? Didn’t these hominins engage in funerary practices just like modern humans do?

If the answer to these questions is yes, then for some people it undermines the case for human uniqueness and exceptionalism and, along with it, the scientific case for the image of God. If Neanderthal funerary practices flow out of the capacity for symbolism, open-ended generative capacity, etc., then it means that Neanderthals must have been like us. They must have been exceptional, too, and humans don’t stand apart from all other creatures on Earth, as the Scriptures teach.

Did Neanderthals Bury Their Dead?

But, could these notions about Neanderthal exceptionalism be premature? Although there is widespread belief that Neanderthals buried their dead in a ritualistic manner and even though this claim can be attested in the scientific literature, a growing body of archeological evidence challenges this view.

Many anthropologists question if Neanderthal burials were in fact ritualistic. (If they weren’t, then it most likely indicates that these hominins didn’t have a concept of the afterlife—a concept that requires symbolism and open-ended generative capacities.) Others go so far as to question if Neanderthals buried their dead at all. (For an in-depth discussion of the scientific challenges to Neanderthal burials, see the Resources section below.)

Were Neanderthal Burials an Evolutionary Precursor to Human Funerary Practices?

It is not unreasonable to think that these hominins may well have disposed of corpses and displayed some type of response when members of their group died. Over the centuries, keen observers (including primatologists, most recently) have documented nonhuman primates inspecting, protecting, retrieving, carrying, and dragging the dead bodies of members of their groups.1 In light of these observations, it makes sense to think that Neanderthals may have done something similar.

While it doesn’t appear that Neanderthals responded to death in the same way we do, it is tempting (within the context of the evolutionary paradigm) to view Neanderthal behavior as an evolutionary stepping-stone to the funerary practices of modern humans.

But, is this transitional view the best explanation for Neanderthal burials—assuming that these hominins did, indeed, dispose of group members’ corpses? Research in thanatology (the study of dying and death) among nonhuman primates holds the potential to shed light on this question.

The Nonhuman Primate Response to Death

Behavioral evolution researchers André Gonçalves and Susana Caravalho recently reviewed studies in primate thanatology—categorizing and interpreting the way these creatures respond to death. In the process, they sought to explain the role the death response plays among various primate groups.

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Figure 1: Monkey Sitting over the Body of a Deceased Relative. Image credit: Shutterstock

When characterizing the death response of nonhuman primates, Gonçalves and Caravalho group the behaviors of these creatures into two categories: (1) responses to infant deaths and (2) responses to adult deaths.

In most primate taxa (classified groups), when an infant dies the mother will carry the dead baby for days before abandoning it, often grooming the corpse and swatting away flies. Eventually, she will abandon it. Depending on the taxon, in some instances young females will carry the infant’s remains for a few days after the mother abandons it. Most other members in the group ignore the corpse. At times, they will actively avoid both mother and corpse when the stench becomes overwhelming.

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Figure 2: Baboon Mother with a Child. Image credit: Shutterstock

The death of an adult member of the group tends to elicit a much more pervasive response than does the death of an infant. The specific nature of the response depends upon the taxon and also on other factors such as: (1) the bond between individual members of the group and the deceased; (2) the social status of the deceased; and (3) the group structure of the particular taxon. Typically, the closer the bond between the deceased and the group member the longer the duration of the death response. The same is true if the deceased is a high-ranking member of the group.

Often the death response includes vocalizations that connote alarm and distress. Depending on the taxon, survivors may hit and pull at the corpse, as if trying to rouse it. Other times, it appears that survivors hit the corpse out of frustration. Sometimes groups members will sniff at the corpse or peer at it. In some taxa, survivors will groom the corpse or stroke it gently, while swatting away flies. In other taxa, survivors will stand vigil over the corpse, guarding it from scavengers.

In some instances, survivors return to the corpse and visit it for days. After the corpse is disposed, group members may continue to visit the site for quite some time. In other taxa, group members may avoid the death site. Both behaviors indicate that group members understand that an event of great importance to the group took place at the site where a member died.

Are Humans and Nonhuman Primates Different in Degree? Or Kind?

It is clear that nonhuman primates have an awareness of death and, for some primate taxa, it seems as if members of the group experience grief. Some anthropologists and primatologists see this behavior as humanlike. It’s easy to see why. We are moved by the anguish and confusion these creatures seem to experience when one of their group members dies.

For the most part, these scientists would agree that the human response to death is more complex and sophisticated. Yet, they see human behavior as differing only in degree rather than kind when compared to other primates. Accordingly, they interpret primate death awareness as an evolutionary antecedent to the sophisticated funerary practices of modern humans, with Neanderthal behavior part of the trajectory. And for this reason, they maintain that human beings really aren’t unique or exceptional.

The Trouble with Anthropomorphism

One problem with this conclusion (even within an evolutionary framework) is that it fails to account for the human tendency toward anthropomorphism. As part of our human nature, we possess theory of mind. We recognize that other human beings have minds like ours. And because of this capability, we know what other people are thinking and feeling. But, we don’t know how to turn this feature on and off. As a result, we also apply theory of mind to animals and inanimate objects, attributing humanlike behaviors and motivations to them, though they don’t actually possess these qualities.

British ethnologist Marian Stamp Dawkins argues in her book Why Animals Matter that scientists studying animal behavior fall victim to the tendency to anthropomorphize just as easily as the rest of us. Too often, researchers interpret experimental results from animal behavioral studies and from observations of animal behavior in captivity and the wild in terms of human behavior. When they do, these researchers ascribe human mental experiences—thoughts and feelings—to animals. Dawkins points out that when investigators operate this way, it leads to untestable hypotheses because we can never truly know what occurs in animal minds. Moreover, Dawkins argues that we tend to prefer anthropomorphic interpretations to other explanations. She states, “Anthropomorphism tends to make people go for the most human-like explanation and ignore the other less exciting ones.”2

A lack of awareness of our tendency toward anthropomorphism raises questions about the all-too-common view that the death response of nonhuman primates—and Neanderthals—is humanlike and an evolutionary antecedent to modern human funerary practices. This is especially true in light of the explanation offered by Gonçalves and Caravalho for the death response in primates.

The two investigators argue that the response of mothers to the death of their infants is actually maladaptive (from an evolutionary perspective). Carrying around dead infants and caring for them is energetically costly and hinders their locomotion. Both consequences render them vulnerable to predators. The pair explain this behavior by arguing that the mother’s response to the death of her infant falls on the continuum of care-taking behavior and can be seen as a trade-off. In other words, nonhuman primate mothers who have a strong instinct to care for their offspring will ensure the survival of their infant. But if the infant dies, the instinct is so strong that they will continue to care for it after its death.

Gonçalves and Caravalho also point out that the death response toward adult members of the group plays a role in reestablishing new group dynamics. Depending on the primate taxon, the death of members shifts the group’s hierarchical structure. This being the case, it seems reasonable to think that the death response helps group members adjust to the new group structure as survivors take on new positions in the hierarchy.

Finally, as Dawkins argues, we can’t know what takes place in the minds of animals. Therefore, we can’t legitimately attribute human mental experiences to animals. So, while it may seem to us as if some nonhuman primates experience grief as part of the death response, how do we know that this is actually the case? Evidence for grief often consists of loss of appetite and increased vocalizations. However, though these changes occur in response to the death of a group member, there may be other explanations for these behaviors that have nothing to do with grief at all.

Death Response in Nonhuman Primates and Neanderthals

Study of primate thanatology also helps us to put Neanderthal burial practices (assuming that these hominins buried dead group members) into context. Often, when anthropologists interpret Neanderthal burials (from an evolutionary perspective), they are comparing these practices to human funerary practices. This comparison makes it seem like Neanderthal burials are part of an evolutionary trajectory toward modern human behavior and capabilities.

But what if the death response of nonhuman primates is factored into the comparison? When we add a second endpoint, we find that the Neanderthal response to death clusters more closely to the responses displayed by nonhuman primates than to modern humans. And as remarkable as the death response of nonhuman primates may be, it is categorically different from modern human funerary practices. To put it another way, modern human funerary practices reflect our capacity for symbolism, open-ended manipulation of symbols, theory of mind, etc. In contrast, the death response of nonhuman primates and hominins, such as Neanderthals, seems to serve utilitarian purposes. So, it isn’t the presence or absence of the death response that determines our exceptional nature. Instead, it is a death response shaped by our capacity for symbolism and open-ended generative capacity that highlights our exceptional uniqueness.

Modern humans really do seem to stand apart compared to all other creatures in a way that aligns with the biblical claim that human beings uniquely possess and express the image of God.

RTB’s biblical creation model for human origins, described in Who Was Adam?, views hominins such as Neanderthals as creatures created by God’s divine fiat that possess intelligence and emotional capacity. These animals were able to employ crude tools and even adopt some level of “culture,” much like baboons, gorillas, and chimpanzees. But they were not spiritual beings made in God’s image. That position—and all of the intellectual, relational, and symbolic capabilities that come with it—remains reserved for modern humans alone.

Resources for Further Exploration

Did Neanderthals Bury Their Dead?

Nonhuman Primate Behavior

Problem-Solving in Animals and Human Exceptionalism

Endnotes
  1. André Gonçalves and Susana Caravalho, “Death among Primates: A Critical Review of Nonhuman Primate Interactions towards Their Dead and Dying,” Biological Reviews 94, no. 4 (April 4, 2019), doi:10.1111/brv.12512.
  2. Marian Stamp Dawkins, Why Animals Matter: Animal Consciousness, Animal Welfare, and Human Well-Being (New York, Oxford University Press, 2012), 30.

Reprinted with permission by the author

Original article at:

https://reasons.org/explore/blogs/the-cells-design

Timing of Neanderthals’ Disappearance Makes Art Claims Unlikely

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BY FAZALE RANA – MARCH 27, 2019

In Latin it literally means, “somewhere else.”

Legal experts consider an alibi to be one of the most effective legal defenses available in a court of law because it has the potential to prove a defendant’s innocence. It goes without saying: if a defendant has an alibi, it means that he or she was somewhere else when the crime was committed.

As it turns out, paleoanthropologists have discovered that Neanderthals have an alibi, of sorts. Evidence indicates that they weren’t the ones to scratch up the floor of Gorham’s Cave.

Based on recent radiocarbon dates measured for samples from Bajondillo Cave (located on the southern part of the Iberian Peninsula—southwest corner of Europe), a research team from the Japan Agency for Marine-Earth Science and Technology and several Spanish institutions determined that modern humans made their way to the southernmost tip of Iberia around 43,000 years ago, displacing Neanderthals.1

Because Neanderthals disappeared from Iberia at that time, it becomes unlikely that they were responsible for hatch marks (dated to be 39,000 years in age) made on the floor of Gorham’s Cave on the island of Gibraltar. These scratches have been interpreted by some paleoanthropologists as evidence that Neanderthals possessed symbolic capabilities.

But how could Neanderthals have made the hatch marks if they weren’t there? Ladies and gentlemen of the jury: the perfect alibi. Instead, it looks as if modern humans were the culprits who marked up the cave floor.

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Figure 1: Gorham’s Cave. Image credit: Wikipedia

The Case for Neanderthal Exceptionalism

Two of the biggest questions in anthropology today relate to Neanderthals:

  • When did these creatures disappear from Europe?
  • Did they possess symbolic capacity like modern humans, thus putting their cognitive abilities on par with ours as a species?

For paleoanthropologists, these two questions have become inseparable. With regard to the second question, some paleoanthropologists are convinced that Neanderthals displayed symbolic capabilities.

It is important to note that the case for Neanderthal symbolism is largely based on correlations between the archaeological and fossil records. Toward this end, some anthropologists have concluded that Neanderthals possessed symbolism because researchers have recovered artifacts (presumably reflecting symbolic capabilities) from the same layers that harbored Neanderthal fossils. Unfortunately, this approach is complicated by other studies that show that the cave layers have been mixed by either cave occupants (either hominid or modern human) or animals living in the caves. This mixing leads to the accidental association of fossil and archaeological remains. In other words, the mixing of layers raises questions about who the manufacturers of these artifacts were.

Because we know modern humans possess the capacity for symbolism, it is much more likely that modern humans, not Neanderthals, made the symbolic artifacts, in these instances. Then, only through an upheaval of the cave layers did the artifacts mix with Neanderthal remains. (See the Resources section for articles that elaborate this point.)

More often than not, archaeological remains are unearthed by themselves with no corresponding fossil specimens. This is the reason why understanding the timing of Neanderthals’ disappearance and modern humans’ arrival in different regions of Europe becomes so important (and why the two questions interrelate). Paleoanthropologists believe that if they can show that Neanderthals lived in a locale at the time symbolic artifacts were produced, then it becomes conceivable that these creatures made the symbolic items. This interpretation increases in plausiblity if no modern humans were around at the time.

Some researchers have argued along these lines regarding the hatch marks found on the floor of Gorham’s Cave.2 The markings were made in the bedrock of the cave floor. The layers above the bedrock date to between 30,000 and 39,000 years in age. Some paleoanthropologists argue that Neanderthals must have made the markings. Why? Because, even though modern humans were already in Europe by that time, these paleoanthropologists think that modern humans had not yet made their way to the southern part of the Iberian Peninsula. These same researchers also think that Neanderthals survived in Iberia until about 32,000 years ago, even though their counterparts in other parts of Europe had already disappeared. So, on this basis, paleoanthropologists conclude that Neanderthals produced the hatch marks and, thus, displayed symbolic capabilities.

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Figure 2: Hatch marks on the floor of Gorham’s Cave. Image credit: Wikipedia

When Did Neanderthals Disappear from Iberia?

But recent work challenges this conclusion. The Spanish and Japanese team took 17 new radiocarbon measurements from layers of the Bajondillo Cave (located in southern Iberia, near Gorham’s Cave) with the hopes of precisely documenting the change in technology from Mousterian (made by Neanderthals) to Aurignacian (made by modern humans). This transition corresponds to the replacement of Neanderthals by modern humans elsewhere in Europe.

The researchers combined the data from their samples with previous measurements made at the site to pinpoint this transition at around 43,000 years ago—not 32,000 years ago. In other words, modern humans occupied Iberia at the same time they occupied other places in Europe. This result also means that Neanderthals had disappeared from Iberia well before the hatch marks in Gorham’s Cave were made.

Were Neanderthals Exceptional Like Modern Humans?

Though claims of Neanderthal exceptionalism abound in the scientific literature and in popular science articles, the claims universally fail to withstand ongoing scientific scrutiny, as this latest discovery attests. Simply put, based on the archaeological record, there are no good reasons to think that Neanderthals displayed symbolism.

From my perspective, the case for Neanderthal symbolism seems to be driven more by ideology than actual scientific evidence.

It is also worth noting that comparative studies on Neanderthal and modern human brain structures also lead to the conclusion that humans displayed symbolism and Neanderthals did not. (See the Resources section for articles that describe this work in more detail.)

Why Does It Matter?

Questions about Neanderthal symbolic capacity and, hence, exceptionalism have bearing on how we understand human beings. Are human beings unique in our capacity for symbolism or is this quality displayed by other hominins? If humans are not alone in our capacity for symbolism, then we aren’t exceptional. And, if we aren’t exceptional then it becomes untenable to embrace the biblical concept of human beings as God’s image bearers. (As a Christian, I see symbolism as a manifestation of the image of God.)

But, based on the latest scientific evidence, the verdict is in: modern humans are the only species to display the capacity for symbolism. In this way, scientific advance affirms that humans are exceptional in a way that aligns with the biblical concept of the image of God.

The Neanderthals’ alibi holds up. They weren’t there, but humans were. Case closed.

Resources

Endnotes
  1. Miguel Cortés-Sánchez et al., “An Early Aurignacian Arrival in Southwestern Europe,” Nature Ecology and Evolution 3 (January 21, 2019): 207–12, doi:10.1038/s41559-018-0753-6.
  2. Joaquín Rodríguez-Vidal et al., “A Rock Engraving Made by Neanderthals in Gibraltar,” Proceedings of the National Academy of Sciences USA 111, no. 37 (September 16, 2014): 13301–6, doi:10.1073/pnas.1411529111.

Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2019/03/27/timing-of-neanderthals-disappearance-makes-art-claims-unlikely

Did Neanderthals Start Fires?

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BY FAZALE RANA – DECEMBER 5, 2018

It is one of the most iconic Christmas songs of all time.

Written by Bob Wells and Mel Torme in the summer of 1945, “The Christmas Song” (subtitled “Chestnuts Roasting on an Open Fire”) was crafted in less than an hour. As the story goes, Wells and Torme were trying to stay cool during the blistering summer heat by thinking cool thoughts and then jotting them down on paper. And, in the process, “The Christmas Song” was born.

Many of the song’s lyrics evoke images of winter, particularly around Christmastime. But none has come to exemplify the quiet peace of a Christmas evening more than the song’s first line, “Chestnuts roasting on an open fire . . . ”

Gathering around the fire to stay warm, to cook food, and to share in a community has been an integral part of the human experience throughout history—including human prehistory. Most certainly our ability to master fire played a role in our survival as a species and in our ability as human beings to occupy and thrive in some of the world’s coldest, harshest climates.

But fire use is not limited only to modern humans. There is strong evidence that Neanderthals made use of fire. But, did these creatures have control over fire in the same way we do? In other words, did Neanderthals master fire? Or, did they merely make opportunistic use of natural fires? These questions are hotly debated by anthropologists today and they contribute to a broader discussion about the cognitive capacity of Neanderthals. Part of that discussion includes whether these creatures were cognitively inferior to us or whether they were our intellectual equals.

In an attempt to answer these questions, a team of researchers from the Netherlands and France characterized the microwear patterns on bifacial (having opposite sides that have been worked on to form an edge) tools made from flint recovered from Neanderthal sites, and concluded that the wear patterns suggest that these hominins used pyrite to repeatedly strike the flint. This process generates sparks that can be used to start fires.1 To put it another way, the researchers concluded that Neanderthals had mastery over fire because they knew how to start fires.

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Figure 1: Biface tools for cutting or scraping. Image credit: Shutterstock

However, a closer examination of the evidence along with results of other studies, including recent insight into the cause of Neanderthal extinction, raises significant doubts about this conclusion.

What Do the Microwear Patterns on Flint Say?

The investigators focused on the microwear patterns of flint bifaces recovered from Neanderthal sites as a marker for fire mastery because of the well-known practice among hunter-gatherers and pastoralists of striking flint with pyrite (an iron disulfide mineral) to generate sparks to start fires. Presumably, the first modern humans also used this technique to start fires.

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Figure 2: Starting a fire with pyrite and flint. Image credit: Shutterstock

The research team reasoned that if Neanderthals started fires, they would use a similar tactic. Careful examination of the microwear patterns on the bifaces led the research team to conclude that these tools were repeatedly struck by hard materials, with the strikes all occurring in the same direction along the bifaces’ long axis.

The researchers then tried to experimentally recreate the microwear pattern in a laboratory setting. To do so, they struck biface replicas with a number of different types of materials, including pyrites, and concluded that the patterns produced by the pyrite strikes most closely matched the patterns on the bifaces recovered from Neanderthal sites. On this basis, the researchers claim that they have found evidence that Neanderthals deliberately started fires.

Did Neanderthals Master Fire?

While this conclusion is possible, at best this study provides circumstantial, not direct, evidence for Neanderthal mastery of fire. In fact, other evidence counts against this conclusion. For example, bifaces with the same type of microwear patterns have been found at other Neanderthal sites, locales that show no evidence of fire use. These bifaces would have had a range of usages, including butchery of the remains of dead animals. So, it is possible that these tools were never used to start fires—even at sites with evidence for fire usage.

Another challenge to the conclusion comes from the failure to detect any pyrite on the bifaces recovered from the Neanderthal sites. Flint recovered from modern human sites shows visible evidence of pyrite. And yet the research team failed to detect even trace amounts of pyrite on the Neanderthal bifaces during the course of their microanalysis.

This observation raises further doubt about whether the flint from the Neanderthal sites was used as a fire starter tool. Rather, it points to the possibility that Neanderthals struck the bifaces with materials other than pyrite for reasons not yet understood.

The conclusion that Neanderthals mastered fire also does not square with results from other studies. For example, a careful assessment of archaeological sites in southern France occupied by Neanderthals from about 100,000 to 40,000 years ago indicates that Neanderthals could not create fire. Instead, these hominins made opportunistic use of natural fire when it was available to them.2

These French sites do show clear evidence of Neanderthal fire use, but when researchers correlated the archaeological layers displaying evidence for fire use with the paleoclimate data, they found an unexpected pattern. Neanderthals used fire during warm climate conditions and failed to use fire during cold periods—the opposite of what would be predicted if Neanderthals had mastered fire.

Lightning strikes that would generate natural fires are much more likely to occur during warm periods. Instead of creating fire, Neanderthals most likely harnessed natural fire and cultivated it as long as they could before it extinguished.

Another study also raises questions about the ability of Neanderthals to start fires.3 This research indicates that cold climates triggered Neanderthal extinctions. By studying the chemical composition of stalagmites in two Romanian caves, an international research team concluded that there were two prolonged and extremely cold periods between 44,000 and 40,000 years ago. (The chemical composition of stalagmites varies with temperature.)

The researchers also noted that during these cold periods, the archaeological record for Neanderthals disappears. They interpret this disappearance to reflect a dramatic reduction in Neanderthal population numbers. Researchers speculate that when this population downturn took place during the first cold period, modern humans made their way into Europe. Being better suited for survival in the cold climate, modern human numbers increased. When the cold climate mitigated, Neanderthals were unable to recover their numbers because of the growing populations of modern humans in Europe. Presumably, after the second cold period, Neanderthal numbers dropped to the point that they couldn’t recover, and hence, became extinct.

But why would modern humans be more capable than Neanderthals of surviving under extremely cold conditions? It seems as if it should be the other way around. Neanderthals had a hyper-polar body design that made them ideally suited to withstand cold conditions. Neanderthal bodies were stout and compact, comprised of barrel-shaped torsos and shorter limbs, which helped them retain body heat. Their noses were long and sinus cavities extensive, which helped them warm the cold air they breathed before it reached their lungs. But, despite this advantage, Neanderthals died out and modern humans thrived.

Some anthropologists believe that the survival discrepancy could be due to dietary differences. Some data indicates that modern humans had a more varied diet than Neanderthals. Presumably, these creatures primarily consumed large herbivores—animals that disappeared when the climatic conditions turned cold, thereby threatening Neanderthal survival. On the other hand, modern humans were able to adjust to the cold conditions by shifting their diets.

But could there be a different explanation? Could it be that with their mastery of fire, modern humans were able to survive cold conditions? And did Neanderthals die out because they could not start fires?

Taken in its entirety, the data seems to indicate that Neanderthals lacked mastery of fire but could use it opportunistically. And, in a broader context, the data indicates that Neanderthals were cognitively inferior to humans.

What Difference Does It Make?

One of the most important ideas taught in Scripture is that human beings uniquely bear God’s image. As such, every human being has immeasurable worth and value. And because we bear God’s image, we can enter into a relationship with our Maker.

However, if Neanderthals possessed advanced cognitive ability just like that of modern humans, then it becomes difficult to maintain the view that modern humans are unique and exceptional. If human beings aren’t exceptional, then it becomes a challenge to defend the idea that human beings are made in God’s image.

Yet, claims that Neanderthals are cognitive equals to modern humans fail to withstand scientific scrutiny, time and time, again. Now it’s time to light a fire in my fireplace and enjoy a few contemplative moments thinking about the real meaning of Christmas.

Resources

Endnotes

  1. A. C. Sorensen, E. Claud, and M. Soressi, “Neanderthal Fire-Making Technology Inferred from Microwear Analysis,” Scientific Reports 8 (July 19, 2018): 10065, doi:10.1038/s41598-018-28342-9.
  2. Dennis M. Sandgathe et al., “Timing of the Appearance of Habitual Fire Use,” Proceedings of the National Academy of Sciences, USA 108 (July 19, 2011), E298, doi:10.1073/pnas.1106759108; Paul Goldberg et al., “New Evidence on Neandertal Use of Fire: Examples from Roc de Marsal and Pech de l’Azé IV,” Quaternary International 247 (2012): 325–40, doi:10.1016/j.quaint.2010.11.015; Dennis M. Sandgathe et al., “On the Role of Fire in Neandertal Adaptations in Western Europe: Evidence from Pech de l’Azé IV and Roc de Marsal, France,” PaleoAnthropology (2011): 216–42, doi:10.4207/PA.2011.ART54.
  3. Michael Staubwasser et al., “Impact of Climate Change on the Transition of Neanderthals to Modern Humans in Europe,” Proceedings of the National Academy of Sciences, USA 115 (September 11, 2018): 9116–21, doi:10.1073/pnas.1808647115.
Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2018/12/05/did-neanderthals-start-fires?fbclid=IwAR1_nl_nJgjbbrRmVrRQjIhFcrSrTaNtdJHQcdfhz4FgAOrykOGIGHmSum4

When Did Modern Human Brains—and the Image of God—Appear?

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BY FAZALE RANA – NOVEMBER 14, 2018

When I was a kid, I enjoyed reading Ripley’s Believe It or Not! I couldn’t get enough of the bizarre facts described in the pages of this comic.

I was especially drawn to the panels depicting people who had oddly shaped heads. I found it fascinating to learn about people whose skulls were purposely forced into unnatural shapes by a practice known as intentional cranial deformation.

For the most part, this practice is a thing of the past. It is rarely performed today (though there are still a few people groups who carry out this procedure). But for much of human history, cultures all over the world have artificially deformed people’s crania (often for reasons yet to be fully understood). They accomplished this feat by binding the heads of infants, which distorts the normal growth of the skull. Through this practice, the shape of the human head can be readily altered to be abnormally flat, elongated, rounded, or conical.

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Figure 1: Deformed ancient Peruvian skull. Image credit: Shutterstock.

It is remarkable that the human skull is so malleable. Believe it, or not!

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Figure 2: Parts of the human skull. Image credit: Shutterstock.

For physical anthropologists, the normal shape of the modern human skull is just as bizarre as the conical-shaped skulls found among the remains of the Nazca culture of Peru. Compared to other hominins (such as Neanderthals and Homo erectus), modern humans have oddly shaped skulls. The skull shape of the hominins was elongated along the anterior-posterior axis. But the skull shape of modern humans is globular, with bulging and enlarged parietal and cerebral areas. The modern human skull also has another distinctive feature: the face is retracted and relatively small.

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Figure 3: Comparison of modern human and Neanderthal skulls. Image credit: Wikipedia.

Anthropologists believe that the difference in skull shape (and hence, brain shape) has profound significance and helps explain the advanced cognitive abilities of modern humans. The parietal lobe of the brain is responsible for:

  • Perception of stimuli
  • Sensorimotor transformation (which plays a role in planning)
  • Visuospatial integration (which provides hand-eye coordination needed for throwing spears and making art)
  • Imagery
  • Self-awareness
  • Working and long-term memory

Human beings seem to uniquely possess these capabilities. They make us exceptional compared to other hominins. Thus, for paleoanthropologists, two key questions are: when and how did the globular human skull appear?

Recently, a team of researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, addressed these questions. And their answers add evidence for human exceptionalism while unwittingly providing support for the RTB human origins model.1

The Appearance of the Modern Human Brain

To characterize the mode and tempo for the origin of the unusual morphology (shape) of the modern human skull, the German researchers generated and analyzed the CT scans of 20 fossil specimens representing three windows of time: (1) 300,000 to 200,000 years ago; (2) 130,000 to 100,000 years ago; and (3) 35,000 to 10,000 years ago. They also included 89 cranially diverse skulls from present-day modern humans, 8 Neanderthal skulls, and 8 from Homo erectus in their analysis.

The first group consisted of three specimens: (1) Jebel Irhoud 1 (dating to 315,000 years in age); (2) Jebel Irhoud 2 (also dating to 315,000 years in age); and (3) Omo Kibish (dating to 195,000 years in age). The specimens that comprise this group are variously referred to as near anatomically modern humans or archaic Homo sapiens.

The second group consisted of four specimens: (1) LH 18 (dating to 120,000 years in age); (2) Skhul (dating to 115,000 years in age); (3) Qafzeh 6; and (4) Qafzeh 9 (both dating to about 115,000 years in age. This group consists of specimens typically considered to be anatomically modern humans. The third group consisted of thirteen specimens that are all considered to be anatomically and behaviorally modern humans.

Researchers discovered that the group one specimens had facial features like that of modern humans. They also had brain sizes that were similar to Neanderthals and modern humans. But their endocranial shape was unlike that of modern humans and appeared to be intermediate between H. erectus and Neanderthals.

On the other hand, the specimens from group two displayed endocranial shapes that clustered with the group three specimens and the present-day samples. In short, modern human skull morphology (and brain shape) appeared between 130,000 to 100,000 years ago.

Confluence of Evidence Locates Humanity’s Origin

This result aligns with several recent archaeological finds that place the origin of symbolism in the same window of time represented by the group two specimens. (See the Resources section for articles detailing some of these finds.) Symbolism—the capacity to represent the world and abstract ideas with symbols—appears to be an ability that is unique to modern humans and is most likely a manifestation of the modern human brain shape, specifically an enlarged parietal lobe.

Likewise, this result coheres with the most recent dates for mitochondrial Eve and Y-chromosomal Adam around 120,000 to 150,000 years ago. (Again, see the Resources section for articles detailing some of these finds.) In other words, the confluence of evidence (anatomical, behavioral, and genetic) pinpoints the origin of modern humans (us) between 150,000 to 100,000 years ago, with the appearance of modern human anatomy coinciding with the appearance of modern human behavior.

What Does This Finding Mean for the RTB Human Origins Model?

To be clear, the researchers carrying out this work interpret their results within the confines of the evolutionary framework. Therefore, they conclude that the globular skulls—characteristic of modern humans—evolved recently, only after the modern human facial structure had already appeared in archaic Homo sapiens around 300,000 years ago. They also conclude that the globular skull of modern humans had fully emerged by the time humans began to migrate around the world (around 40,000 to 50,000 years ago).

Yet, the fossil evidence doesn’t show the gradual emergence of skull globularity. Instead, modern human specimens form a distinct cluster isolated from the distinct clusters formed by H. erectus, Neanderthals, and archaic H. sapiens. There are no intermediate globular specimens between archaic and modern humans, as would be expected if this trait evolved. Alternatively, the distinct clusters are exactly as expected if modern humans were created.

It appears that the globularity of our skull distinguishes modern humans from H. erectus, Neanderthals, and archaic Homo sapiens (near anatomically modern humans). This globularity of the modern human skull has implications for when modern human behavior and advanced cognitive abilities emerged.

For this reason, I see this work as offering support for the RTB human origins creation model (and, consequently, the biblical account of human origins and the biblical conception of human nature). RTB’s model (1) views human beings as cognitively superior and distinct from other hominins, and (2) posits that human beings uniquely possess a quality called the image of God that I believe manifests as human exceptionalism.

This work supports both predictions by highlighting the uniqueness and exceptional qualities of modern humans compared to H. erectus, Neanderthals, and archaic H. sapiens, calling specific attention to our unusual skull and brain morphology. As noted, anthropologists believe that this unusual brain morphology supports our advanced cognitive capabilities—abilities that I believe reflect the image of God. Because archaic H. sapiens, Neanderthals, and H. erectus did not possess this brain morphology, it makes it unlikely that these creatures had the sophisticated cognitive capacity displayed by modern humans.

In light of RTB’s model, it is gratifying to learn that the origin of anatomically modern humans coincides with the origin of modern human behavior.

Believe it or not, our oddly shaped head is part of the scientific case that can be made for the image of God.

Resources

Endnotes

  1. Simon Neubauer, Jean-Jacques Hublin, and Philipp Gunz, “The Evolution of Modern Human Brain Shape,” Science Advances 4 (January 24, 2018): eaao596, doi:10.1126/sciadv.aao5961.
Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2018/11/14/when-did-modern-human-brains-and-the-image-of-god-appear

Further Review Overturns Neanderthal Art Claim

furtherreviewoverturns

BY FAZALE RANA – OCTOBER 17, 2018

As I write this blog post, the 2018–19 NFL season is just underway.

During the course of any NFL season, several key games are decided by a controversial call made by the officials. Nobody wants the officials to determine the outcome of a game, so the NFL has instituted a way for coaches to challenge calls on the field. When a call is challenged, part of the officiating crew looks at a computer tablet on the sidelines—reviewing the game footage from a number of different angles in an attempt to get the call right. After two minutes of reviewing the replays, the senior official makes his way to the middle of the field and announces, “Upon further review, the call on the field . . .”

Recently, a team of anthropologists from Spain and the UK created quite a bit of controversy based on a “call” they made from working in the field. Using a new U-Th dating method, these researchers age-dated the artwork in caves from Iberia. Based on the age of a few of their samples, they concluded that Neanderthals produced cave paintings.1 But new work by three independent research teams challenges the “call” from the field—overturning the conclusion that Neanderthals made art and displayed symbolism like modern humans.

U-Th Dating Method

The new dating method under review measures the age of calcite deposits beneath cave paintings and those formed over the artwork after the paintings were created. As water flows down cave walls, it deposits calcite. When calcite forms, it contains trace amounts of U-238. This isotope decays into Th-230. Normally, detection of such low quantities of the isotopes would require extremely large samples. Researchers discovered that by using accelerator mass spectrometry, they could get by with 10-milligram samples. And by dating the calcite samples with this technique, they produced minimum and maximum ages for the cave paintings.2

Call from the Field: Neanderthals Are Artists

The team applied their dating method to the art found in three cave sites in Iberia (ancient Spain): (1) La Pasiega, which houses paintings of animals, linear signs, claviform signs, and dots; (2) Ardales, which contains about 1,000 paintings of animals, along with dots, discs, lines, geometric shapes, and hand stencils; and (3) Maltravieso, which displays a set of hand stencils and geometric designs. The research team took a total of 53 samples from 25 carbonate formations associated with the cave art in these three cave sites. While most of the samples dated to 40,000 years old or less (which indicates that modern humans were the artists), three measurements produced minimum ages of around 65,000 years, including: (1) red scalariform from La Pasiega, (2) red areas from Ardales, and (3) a hand stencil from Maltravieso. On the basis of the three measurements, the team concluded that the art must have been made by Neanderthals because modern humans had not made their way into Iberia at that time. In other words, Neanderthals made art, just like modern humans did.

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Figure: Maltravieso Cave Entrance, Spain. Image credit: Shutterstock

Shortly after the findings were published, I wrote a piece expressing skepticism about this claim for two reasons.

First, I questioned the reliability of the method. Once the calcite deposit forms, the U-Th method will only yield reliable results if none of the U or Th moves in or out of the deposit. Based on the work of researchers from France and the US, it does not appear as if the calcite films are closed systems. The calcite deposits on the cave wall formed because of hydrological activity in the cave. Once a calcite film forms, water will continue to flow over its surface, leeching out U (because U is much more water soluble than Th). By removing U, water flowing over the calcite will make it seem as if the deposit and, hence, the underlying artwork is much older than it actually is.3

Secondly, I expressed concern that the 65,000-year-old dates measured for a few samples are outliers. Of the 53 samples measured, only three gave age-dates of 65,000 years. The remaining samples dated much younger, typically around 40,000 years in age. So why should we give so much credence to three measurements, particularly if we know that the calcite deposits are open systems?

Upon Further Review: Neanderthals Are Not Artists

Within a few months, three separate research groups published papers challenging the reliability of the U-Th method for dating cave art and, along with it, the claim that Neanderthals produced cave art.4 It is not feasible to detail all their concerns in this article, but I will highlight six of the most significant complaints. In several instances, the research teams independently raised the same concerns.

  1. The U-Th method is unreliable because the calcite deposits are an open system. The concern that I raised was reiterated by two of the research teams for the same reason I expressed. The U-Th dating technique can only yield reliable results if no U or Th moves in or out of the system once the calcite film forms. The continued water flow over the calcite deposits will preferentially leech U from the deposit, making the deposit appear to be older than it is.
  2. The U-Th method is unreliable because it fails to account for nonradiogenic Th. This isotope would have been present in the source water producing the calcite deposits. As a result, Th would already be present in calcite at the time of formation. This nonradiogenic Th would make the samples appear to be older than they actually are.
  3. The 65,000-year-old dates for the three measurements from La Pasiega, Ardales, and Maltravieso are likely outliers. Just as I pointed out before, two of the research groups expressed concern that only 3 of the 53 measurements came in at 65,000 years in age. This discrepancy suggests that these dates are outliers, most likely reflecting the fact that the calcite deposits are an open system that formed with Th already present. Yet, the researchers from Spain and the UK who reported these results emphasized the few older dates while downplaying the younger dates.
  4. Multiple measurements on the same piece of art yielded discordant ages. For example, the researchers made five age-date measurements of the hand stencil at Maltravieso. These dates (66.7 kya [thousand years ago], 55.2 kya, 35.3 kya, 23.1 kys, and 14.7 kya) were all over the place. And yet, the researchers selected the oldest date for the age of the hand stencil, without justification.
  5. Some of the red “markings” on cave walls that were dated may not be art. Red markings are commonplace on cave walls and can be produced by microorganisms that secrete organic materials or iron oxide deposits. It is possible that some of the markings that were dated were not art at all.
  6. The method used by the researchers to sample the calcite deposits may have been flawed. One team expressed concern that the sampling technique may have unwittingly produced dates for the cave surface on which the paintings were made rather than the pigments used to make the art itself. If the researchers inadvertently dated the cave surface, it could easily be older than the art.

In light of these many shortcomings, it is questionable if the U-Th method to date cave art is reliable. After review, the call from the field is overturned. There is no conclusive evidence that Neanderthals made art.

Why Does This Matter?

Artistic expression reflects a capacity for symbolism. And many people view symbolism as a quality unique to human beings that contributes to our advanced cognitive abilities and exemplifies our exceptional nature. In fact, as a Christian, I see symbolism as a manifestation of the image of God. If Neanderthals possessed symbolic capabilities, such a quality would undermine human exceptionalism (and with it the biblical view of human nature), rendering human beings nothing more than another hominin. At this juncture, every claim for Neanderthal symbolism has failed to withstand scientific scrutiny.

Now, it is time for me to go back to the game.

Who dey! Who dey! Who dey think gonna beat dem Bengals!

Resources:

Endnotes

  1. L. Hoffmann et al., “U-Th Dating of Carbonate Crusts Reveals Neandertal Origin of Iberian Cave Art,” Science359 (February 23, 2018): 912–15, doi:10.1126/science.aap7778.
  2. W. G. Pike et al., “U-Series Dating of Paleolithic Art in 11 Caves in Spain,” Science 336 (June 15, 2012): 1409–13, doi:10.1126/science.1219957.
  3. Georges Sauvet et al., “Uranium-Thorium Dating Method and Palaeolithic Rock Art,” Quaternary International 432 (2017): 86–92, doi:10.1016/j.quaint.2015.03.053.
  4. Ludovic Slimak et al., “Comment on ‘U-Th Dating of Carbonate Crusts Reveals Neandertal Origin of Iberian Cave Art,’” Science 361 (September 21, 2018): eaau1371, doi:10.1126/science.aau1371; Maxime Aubert, Adam Brumm, and Jillian Huntley, “Early Dates for ‘Neanderthal Cave Art’ May Be Wrong,” Journal of Human Evolution (2018), doi:10.1016/j.jhevol.2018.08.004; David G. Pearce and Adelphine Bonneau, “Trouble on the Dating Scene,” Nature Ecology and Evolution 2 (June 2018): 925–26, doi:10.1038/s41559-018-0540-4.
Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2018/10/17/further-review-overturns-neanderthal-art-claim

Differences in Human and Neanderthal Brains Explain Human Exceptionalism

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BY FAZALE RANA – SEPTEMBER 19, 2018

When I was a little kid, my mom went through an Agatha Christie phase. She was a huge fan of the murder mystery writer and she read all of Christie’s books.

Agatha Christie was caught up in a real-life mystery of her own when she disappeared for 10 days in December 1926 under highly suspicious circumstances. Her car was found near her home, close to the edge of a cliff. But, she was nowhere to be found. It looked as if she disappeared without a trace, without any explanation. Eleven days after her disappearance, she turned up in a hotel room registered under an alias.

Christie never offered an explanation for her disappearance. To this day, it remains an enduring mystery. Some think it was a callous publicity stunt. Some say she suffered a nervous breakdown. Others think she suffered from amnesia. Some people suggest more sinister reasons. Perhaps, she was suicidal. Or maybe she was trying to frame her husband and his mistress for her murder.

Perhaps we will never know.

Like Christie’s fictional detectives Hercule Poirot and Miss Marple, paleoanthropologists are every bit as eager to solve a mysterious disappearance of their own. They want to know why Neanderthals vanished from the face of the earth. And what role did human beings (Homo sapiens) play in the Neanderthal disappearance, if any? Did we kill off these creatures? Did we outcompete them or did Neanderthals just die off on their own?

Anthropologists have proposed various scenarios to account for the Neanderthals’ disappearance. Some paleoanthropologists think that differences in the cognitive capabilities of modern humans and Neanderthals help explain the creatures’ extinction. According to this model, superior reasoning abilities allowed humans to thrive while Neanderthals faced inevitable extinction. As a consequence, we replaced Neanderthals in the Middle East, Europe, and Asia when we first migrated to these parts of the world.

Computational Neuroanatomy

Innovative work by researchers from Japan offers support for this scenario.1 Using a technique called computational neuroanatomy, researchers reconstructed the brain shape of Neanderthals and modern humans from the fossil record. In their study, the researchers used four Neanderthal specimens:

  • Amud 1 (50,000 to 70,000 years in age)
  • La Chapelle-aux Saints 1 (47,000 to 56,000 years in age)
  • La Ferrassie 1 (43,000 to 45,000 years in age)
  • Forbes’ Quarry 1 (no age dates)

They also worked with four Homo sapiens specimens:

  • Qafzeh 9 (90,000 to 120,000 years in age)
  • Skhūl 5 (100,000 to 135,000 years in age
  • Mladeč 1 (35,000 years in age)
  • Cro-Magnon 1 (32,000 years in age)

Researchers used computed tomography scans to construct virtual endocasts (cranial cavity casts) of the fossil brains. After generating endocasts, the team determined the 3D brain structure of the fossil specimens by deforming the 3D structure of the average human brain so that it fit into the fossil crania and conformed to the endocasts.

This technique appears to be valid, based on control studies carried out on chimpanzee and bonobo brains. Using computational neuroanatomy, researchers can deform a chimpanzee brain to accurately yield the bonobo brain, and vice versa.

Brain Differences, Cognitive Differences

The Japanese team learned that the chief difference between human and Neanderthal brains is the size and shape of the cerebellum. The cerebellar hemisphere is projected more toward the interior in the human brain than in the Neanderthal brain and the volume of the human cerebellum is larger. Researchers also noticed that the right side of the Neanderthal cerebellum is significantly smaller than the left side—a phenomenon called volumetric laterality. This discrepancy doesn’t exist in the human brain. Finally, the Japanese researchers observed that the parietal regions in the human brain were larger than those regions in Neanderthals’ brains.

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Image credit: Shutterstock

 

Because of these brain differences, the researchers argue that humans were socially and cognitively more sophisticated than Neanderthals. Neuroscientists have discovered that the cerebellum helps motor functions and higher cognition by contributing to language function, working memory, thought, and social abilities. Hence, the researchers argue that the reduced size of the right cerebellar hemisphere in Neanderthals limits the connection to the prefrontal regions—a connection critical for language processing. Neuroscientists have also discovered that the parietal lobe plays a role in visuo-spatial imagery, episodic memory, self-related mental representations, coordination between self and external spaces, and sense of agency.

On the basis of this study, it seems that humans either outcompeted Neanderthals for limited resources—driving them to extinction—or simply were better suited to survive than Neanderthals because of superior mental capabilities. Or perhaps their demise occurred for more sinister reasons. Maybe we used our sophisticated reasoning skills to kill off these creatures.

Did Neanderthals Make Art, Music, Jewelry, etc.?

Recently, a flurry of reports has appeared in the scientific literature claiming that Neanderthals possessed the capacity for language and the ability to make art, music, and jewelry. Other studies claim that Neanderthals ritualistically buried their dead, mastered fire, and used plants medicinally. All of these claims rest on highly speculative interpretations of the archaeological record. In fact, other studies present evidence that refutes every one of these claims (see Resources).

Comparisons of human and Neanderthal brain morphology and size become increasingly important in the midst of this controversy. This recent study—along with previous work (go here and here)—indicates that Neanderthals did not have the brain architecture and, hence, cognitive capacity to communicate symbolically through language, art, music, and body ornamentation. Nor did they have the brain capacity to engage in complex social interactions. In short, Neanderthal brain anatomy does not support any interpretation of the archaeological record that attributes advanced cognitive abilities to these creatures.

While this study provides important clues about the disappearance of Neanderthals, we still don’t know why they went extinct. Nor do we know any of the mysterious details surrounding their demise as a species.

Perhaps we will never know.

But we do know that in terms of our cognitive and social capacities, human beings stand apart from Neanderthals and all other creatures. Human brain biology and behavior render us exceptional, one-of-a-kind, in ways consistent with the image of God.

Resources

Endnotes

  1. Takanori Kochiyama et al., “Reconstructing the Neanderthal Brain Using Computational Anatomy,” Science Reports 8 (April 26, 2018): 6296, doi:10.1038/s41598-018-24331-0.
Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2018/09/19/differences-in-human-and-neanderthal-brains-explain-human-exceptionalism