Stone-Tipped Weapons: Older than We Thought

Stone-tipped spears have been around for at least 500,000 years, according to new research. That is about 200,000 years earlier than previously thought.

Why is that important? In part because it suggests that modern humans did not invent this technology. They did not get it from the Neandertals, nor did Neandertals get it from modern humans. Instead, it now seems that Neandertals and modern humans both used stone-tipped spears because both inherited this technology from an earlier form of human life.

It is generally believed that Neandertals and modern humans diverged about 500,000 years ago. The current view is that both came from earlier humans known as Homo heidelbergensis.

"Rather than being invented twice, or by one group learning from the other, stone-tipped spear technology was in place much earlier," according to Benjamin Schoville, who coauthored the study and is affiliated with the Institute of Human Origins at Arizona State University. "Although both Neandertals and humans used stone-tipped spears, this is the first evidence that this technology originated prior to or near the divergence of these two species," Schoville said according to a press release from his university.

Caption: A ~500,000-year-old point from Kathu Pan 1. Multiple lines of evidence indicate that points from Kathu Pan 1 were used as hafted spear tips. Scale bar = 1 cm. Credit: Jayne Wilkins. Usage Restrictions: Image may be used to illustrate coverage of this research only.

"This changes the way we think about early human adaptations and capacities before the origin of our own species," said Jayne Wilkins, a lead author from the University of Toronto. Technological advance—in this case stone-tipped spears—is now seen as more widely shared among the various forms of humanity and not so confined to anatomically modern humans like us. Creating stone-tipped spears requires more forethought and care than simpler stone tools, especially in preparing the tips for mounting to the wooden shaft of the spear. This process is called “hafting,” and the result is that a more efficient hunting weapon is created.

In this study, researchers re-examined stone points discovered more than thirty years ago. By comparing the damage to the spear tips with simulated damage re-created under laboratory conditions, researchers found evidence that strongly supports the view that the original tips were used for spears.

"When points are used as spear tips, there is a lot of damage that forms at the tip of the point, and large distinctive fractures form. The damage on these ancient stone spear points is remarkably similar to those produced with our calibrated crossbow experiment, and we demonstrate they are not easily created from other processes," said coauthor Kyle Brown, a skilled stone tool replicator from the University of Cape Town.

Brown, along with others who worked on the current paper, also collaborated on a study just released describing further stone weapons refinements that occurred about 70,000 years ago and probably gave modern humans an advantage over Neadertals. For more on that, see Better Technology, Better Weapons.

The most recent findings that push the date of stone-tipped spears back to 500,000 years ago are published as "Evidence for Early Hafted Hunting Technology" in the November 16, 2012 issue of Science.

A Living, Breathing Lung-on-a-Chip

Human cells can be grown outside the human body. In a petri dish, they may develop in ways that resemble the cells inside the body. But their function and activity are limited. For example, in a dish, lung cells are just lung cells. They don’t breathe.

Using new technology, however, researchers have put lung cells on a chip. The cells on a chip have suddenly become a lung-on-a-chip, active, moving, and breathing.

In a paper published in the in the November 7 issue of Science Translational Medicine, researchers report on their use of recently-developed organ-on-a-chip technology. They describe how they built and used "a biomimetic microdevice that reconstitutes organ-level lung functions to create a human disease model-on-a-chip."

Caption: Wyss Institute's human breathing lung-on-a-chip. Credit: Wyss Institute, Harvard University. Usage Restrictions: None.

Already the device has led to two discoveries directly applicable to the lung disease, edema, which is a major concern for some cancer patients. First, development of the disease is accelerated by the physical movement of the lungs. This is "something that clinicians and scientists never suspected before," according to Donald Ingber, senior author of the study.

Second, researchers identified one drug, currently under development, that might help prevent the problem. For Ingber, this is the main attraction of organ-on-a-chip technology. "This on-chip model of human pulmonary edema can be used to identify new potential therapeutic agents in vitro," Ingber says.

This could accelerate the speed of drug development and testing while reducing the cost. The main advantage is that an organ-on-a-chip gives researchers the opportunity to test a wide array of potential drug compounds. Tests can be run not just on nonhuman animals or on cultured human cells but on functioning or working small-scale models of human organs.

Beyond its value in pharmaceutical research, it is not clear where this research may lead, but it is one more way in which the boundary we once drew between the living and the nonliving is being erased, along with the line between the natural and the artifical.

The work was funded by the National Institutes of Health (NIH) and the Food and Drug Administration (FDA), Defense Advanced Research Projects Agency (DARPA), and the Wyss Institute for Biologically Inspired Engineering at Harvard University. The paper is entitled "A Human Disease Model of Drug Toxicity–Induced Pulmonary Edema in a Lung-on-a-Chip Microdevice" and appears in the November 7, 2012 issue of Science Translational Medicine.

Better Technology, Better Weapons

Ongoing archeological discoveries from coastal South Africa point consistently to a technological and cultural explosion occurring there more than 70,000 years ago. The latest paper, appearing in the November 7 issue of the journal Nature, fills in more detail about remarkable advances in stone tool technology that only appear in Europe some 50,000 years later.

The new findings, reported by an international team of researchers led by Curtis Marean, help fill in a more comprehensive picture of the culture that flourished on the coast of South Africa for thousands of years. In 2009, Marean's team published a report showing how the controlled use of fire played a key role in the engineering of stone tools. The 2012 paper provides evidence that this technology was used for at least 11,000 years by the inhabitants of the coast.

"Eleven thousand years of continuity is, in reality, an almost unimaginable time span for people to consistently make tools the same way," said Marean. "This is certainly not a flickering pattern."

PHOTO: Caption: These microlith blades show a flat edge with a rounded "cutting" edge. Credit: Simen Oestmo. Used by permission of the ASU Institute of Human Origins for the purposes of illustrating coverage of the accompanying article.

One possibility suggested by this research is that the 70,000 year old technology found in South Africa was brought out of Africa by modern humans. If so, it may help explain why Neandertals disappeared as modern humans entered Europe and Asia. Advances in technology made it possible to create light-weight points for spears or arrows, mostly likely used for small spears launched by spear-throwing devices known as atlatls, which effectively extend the length of the throwing arm.

"When Africans left Africa and entered Neanderthal territory they had projectiles with greater killing reach, and these early moderns probably also had higher levels of pro-social (hyper-cooperative) behavior. These two traits were a knockout punch. Combine them, as modern humans did and still do, and no prey or competitor is safe," said Marean. "This probably laid the foundation for the expansion out of Africa of modern humans and the extinction of many prey as well as our sister species such as Neanderthals."

If there is any truth to this conjecture, it is a sobering truth. This technological advance makes it easier to kill.

The new paper reports on findings at the Pinnacle Point excavation site, a mere some 50 miles from Blombos cave, home to similar findings and to the first "chemical engineering laboratory" for the production of the pigment, ochre. Whoever lived there was technologically and culturally advanced, with all the ambiguities that implies.

The paper, "An Early and Enduring Advanced Technology Originating 71,000 Years Ago in South Africa," appears in the November 7 issue of the journal Nature.

Enhancement at Work: A New Report

A new report on human enhancement and its growing impact on the workplace has just been released by top-level British science and policy groups. The Royal Society, the Academy of Medical Science, the British Academy, and the Royal Academy of Engineering collaborated on a research project throughout 2012, resulting in the November 2012 report.

Image from the cover of Human Enhancement and the Future of Work.

Among the conclusions: "Advances in a range of areas in science and engineering such as neuroscience, regenerative medicine and bionics are already enhancing, or could in the next decade enhance, the physical and cognitive capacity of individuals in the workplace." The report is entitled Human Enhancement and the Future of Work.

Even the advocates of human enhancement find something uniquely troubling about the prospect of enhancement technologies in the workplace. Will employers coerce their workers? Will use of enhancement technology be a non-negotiable prerequisite for success in an increasingly competitive work environment? Will employees have full access to information about potential side-effects?

The report notes the following: "Cognitive-enhancing drugs present the greatest immediate challenge...They are already available without prescription through internet purchasing, are relatively cheap and are increasinly being used by healthy individuals."

In response to these challenges, the report does not recommend sanctions or bans, but it does press the case urgently for widening the dialogue and reforming policies and regulations.

Human Germline Modification: A Step Closer?

Human germline modification—often described as "designer babies—has come a step closer. It has been shown that in nonhuman primates, it is possible to transplant specialized cells that produce sperm. When combined with other steps, this may make germline modification feasible and safe for human use.

The new research involves nonhuman primates. Its purpose is to set the stage for clinical trials in human beings. The goal for using this technique in human beings is to overcome infertility, especially for cancer survivors who were treated with radiation or chemotherapy. In men, that treatment may destroy the ability to produce sperm. If the cancer treatment occurs after puberty, sperm can be stored in advance. But if the treatment occurs before a young boy's body produces sperm, permanent infertility may result.

"Men can bank sperm before they have cancer treatment if they hope to have biological children later in their lives," according to University of Pittsburgh researcher Kyle Orwig, lead researcher. "But that is not an option for young boys who haven't gone through puberty, can't provide a sperm sample, and are many years away from thinking about having babies," Orwig said according to a press release from the university.

Photo by Bertrand Devouard, 2006, available at Wikimedia

No medical solution is now available, but the report published today opens the possibility that in the future, young male cancer survivors will be transplanted with cells that can restore their ability to produce sperm and to become fathers. To be clear: Orwig's group did not work with human subjects. But by showing that the technique works in rhesus monkeys, they help make the case that it could work in humans and should be tried.

"This is the first study to demonstrate that transplanted spermatogonial stem cells can produce functional sperm in higher primates," Orwig said. "This is an important step toward human translation." The study is published in the November 2012 issue of the journal, Cell Stem Cell.

The cells that were transplanted into the rhesus monkeys are called "spermatogonial stem cells" or SSCs. Researchers used frozen or cryopreserved SSCs.

In the future, one possibility is that SSCs might be produced from stem cells, such as induced pluripotent stem cells. In addition, the SSCs might be genetically modified before they are transplanted. In nonhuman animals, this would provide a new way to create transgenic animals for research.

Another possibility is that this technique, if used to restore fertility to men who cannot produce sperm, might also be used for human germline modification. In a 2006 article, Hiroshi Kubota and Ralph L. Brinster (a pioneer in developing this technique) suggested that SSC transplantation may be used for precisely this purpose. "Another potential clinical application using human SSCs is GERMLINE GENE THERAPY" (Capital letters in original). They suggest that "germline gene therapy using SSCs will become a promising and feasible approach, although considerable ethical concerns exist."

What makes all this especially interesting is that by transplanting SSCs, researchers may make it possible for fertility to be restored without the use of in vitro fertilization. The Orwig paper suggests this quite clearly: SSC transplantation may be capable of "enabling the recipient male to father his own genetic children, possibly through normal coitus." If the SSCs are genetically modified first, we would have germline modification without IVF.

When human germline modification is suggested, many find the idea frightening. It is generally assumed that religious people will be universally opposed. That is not true, not even among Catholics.

What the official Catholic position opposes is the destruction of human embryos or even their creation outside the human body, which IVF requires. The Vatican is not opposed to using high tech medicine to create healthy babies.

In 2004, this is what a Vatican commission had to say: “Germ line genetic engineering with a therapeutic goal in man would in itself be acceptable were it not for the fact that is it is hard to imagine how this could be achieved without disproportionate risks especially in the first experimental stage, such as the huge loss of embryos and the incidence of mishaps, and without the use of reproductive techniques. A possible alternative would be the use of gene therapy in the stem cells that produce a man’s sperm, whereby he can beget healthy offspring with his own seed by means of the conjugal act.”

It almost sounds here like the Vatican was suggesting the technique that is being developed. It should be noted that this statement was released while John Paul II was pope. It was drafted by a commission headed by Cardinal Ratzinger, who is now Benedict XVI.

One should not expect Catholics or any other religious community to lead a chorus of praise for human germline modification. At most, one might expect guarded comments from religious leaders, coupled with the demand that this technology be limited to therapy and not used for enhancement. But the key point is this: if human germline modification technology is developed, religious leaders may actually be open to its use.

But if it is developed for therapy, who really thinks it will be limited in that way? If it works to create a healthy baby, why not use it to create a better baby?

The article, entitled "Spermatogonial stem cell transplantation into Rhesus testes regenerates spermatogenesis producing functional sperm," appears in the November 2012 issue of the journal, Cell Stem Cell.