Did Supernovae Inspire Our Hominin Ancestors to Walk Upright?

Did Supernovae Inspire Our Hominin Ancestors to Walk Upright?


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Did ancient supernovae induce proto-humans to walk on two legs, eventually resulting in Homo sapiens with hands free to build cathedrals, design rockets and snap iPhone selfies?

A paper published this week in the Journal of Geology makes the case: Supernovae bombarded Earth with cosmic energy starting as many as 8 million years ago, with a peak some 2.6 million years ago, initiating an avalanche of electrons in the lower atmosphere and setting off a chain of events that feasibly ended with bipedal hominins such as Homo habilis , dubbed "handy man."

Homo habilis reconstruction in the Museo de la Evolución Humana, Burgos, sculpture by Elisabeth Daynes (2010) based on the KNM-ER 1813 cranium (Koobi Fora, Kenya, dated 1.9 Ma). ( CC BY SA 4.0 )

Out of Torched Forests and onto the Savanna

The authors believe atmospheric ionization probably triggered an enormous upsurge in cloud-to-ground lightning strikes that ignited forest fires around the globe. These infernos could be one reason ancestors of Homo sapiens developed bipedalism -- to adapt in savannas that replaced torched forests in northeast Africa.

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"It is thought there was already some tendency for hominins to walk on two legs, even before this event," said lead author Adrian Melott, professor emeritus of physics & astronomy at the University of Kansas.

"But they were mainly adapted for climbing around in trees. After this conversion to savanna, they would much more often have to walk from one tree to another across the grassland, and so they become better at walking upright. They could see over the tops of grass and watch for predators. It's thought this conversion to savanna contributed to bipedalism as it became more and more dominant in human ancestors."

Savanna (and animals) near Kuruman, South Africa. ( Public Domain )

Based on a "telltale" layer of iron-60 deposits lining the world's sea beds, astronomers have high confidence supernovae exploded in Earth's immediate cosmic neighborhood -- between 100 and only 50 parsecs (163 light years) away -- during the transition from the Pliocene Epoch to the Ice Age.

Cosmic Rays and Hominin Bipedalism

"We calculated the ionization of the atmosphere from cosmic rays which would come from a supernova about as far away as the iron-60 deposits indicate," Melott said.

"It appears that this was the closest one in a much longer series. We contend it would increase the ionization of the lower atmosphere by 50-fold. Usually, you don't get lower-atmosphere ionization because cosmic rays don't penetrate that far, but the more energetic ones from supernovae come right down to the surface -- so there would be a lot of electrons being knocked out of the atmosphere."

A supernova. ( NASA)

According to Melott and co-author Brian Thomas of Washburn University, ionization in the lower atmosphere meant an abundance of electrons would form more pathways for lightning strikes.

"The bottom mile or so of atmosphere gets affected in ways it normally never does," Melott said.

"When high-energy cosmic rays hit atoms and molecules in the atmosphere, they knock electrons out of them -- so these electrons are running around loose instead of bound to atoms. Ordinarily, in the lightning process, there's a buildup of voltage between clouds or the clouds and the ground -- but current can't flow because not enough electrons are around to carry it. So, it has to build up high voltage before electrons start moving. Once they're moving, electrons knock more electrons out of more atoms, and it builds to a lightning bolt. But with this ionization, that process can get started a lot more easily, so there would be a lot more lightning bolts."

The KU researcher said the probability that this lightning spike touched off a worldwide upsurge in wildfires is supported by the discovery of carbon deposits found in soils that correspond with the timing of the cosmic-ray bombardment.

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Ionization in the lower atmosphere meant an abundance of electrons would form more pathways for lightning strikes. ( CC0)

"The observation is that there's a lot more charcoal and soot in the world starting a few million years ago," Melott said.

"It's all over the place, and nobody has any explanation for why it would have happened all over the world in different climate zones. This could be an explanation. That increase in fires is thought to have stimulated the transition from woodland to savanna in a lot of places -- where you had forests, now you had mostly open grassland with shrubby things here and there. That's thought to be related to human evolution in northeast Africa. Specifically, in the Great Rift Valley where you get all these hominin fossils."

Hominid fossils in South Africa. ( CC BY SA 3.0 )

Don’t Worry About Supernovae, Solar Flares are Our Concern

Melott said no such event is likely to occur again anytime soon. The nearest star capable of exploding into a supernova in the next million years is Betelgeuse, some 200 parsecs (652 light years) from Earth.

"Betelgeuse is too far away to have effects anywhere near this strong," Melott said. "So, don't worry about this. Worry about solar proton events. That's the danger for us with our technology -- a solar flare that knocks out electrical power. Just imagine months without electricity."


New Human Ancestor Walked Like Us, Climbed Like an Ape

Strong hands and shock-resistant wrists gave the ancient human Homo naledi an advantage over ape cousins.

The mysterious human ancestor called Homo naledi was primed for success in a prehistoric triathlon, new research shows—if the challenges were walking upright, climbing trees, and handily wielding tools.

Based on fossils retrieved from South Africa’s Rising Star cave, two teams reconstructed the locomotor habits of Homo naledi, reported Tuesday in Nature Communications. With funding from National Geographic, one took a close look at 107 foot bones, the other at 26 bones from a nearly complete right hand.

In most respects, the H. naledi foot looks surprisingly like a modern human’s. Its ankle joint, parallel big toe and wide heel bone belong to a striding biped, a creature fully adapted to efficiently walking upright on two legs. But its lower arch and curved toe bones are more ape-like.

The hand, with its curved fingers, indicates that H. naledi were strong climbers—and yet the long, strong thumb and shock-absorbing wrist could also have been capable of manipulating tools (though no tools have been found yet).

It’s a mix of features scientists hadn't seen clearly yet in the genus Homo, to which modern humans belong, particularly when it comes to H. naledi’s pronounced arboreal proclivities.

H. naledi had a unique form of locomotion for a member of the genus Homo,” says study author William Harcourt-Smith of CUNY’s Lehman College.


The experiments used different sources of light, ranging from a laser to white light simulating the solar spectrum.

Researchers from the University of Houston have found a catalyst that can quickly generate hydrogen from water using sunlight, potentially creating a clean and renewable source of energy.

Their research, published online Sunday in Nature Nanotechnology, involved the use of cobalt oxide nanoparticles to split water into hydrogen and oxygen.

Jiming Bao, lead author of the paper and an assistant professor in the Department of Electrical and
Computer Engineering at UH, said the research discovered a new photocatalyst and demonstrated the potential of nanotechnology in engineering a material's property, although more work remains to be done.

Bao said photocatalytic water-splitting experiments have been tried since the 1970s, but this was the first to use cobalt oxide and the first to use neutral water under visible light at a high energy conversion efficiency without co-catalysts or sacrificial chemicals. The project involved researchers from UH, along with those from Sam Houston State University, the Chinese Academy of Sciences, Texas State University, Carl Zeiss Microscopy LLC, and Sichuan University.

Researchers prepared the nanoparticles in two ways, using femtosecond laser ablation and through mechanical ball milling. Despite some differences, Bao said both worked equally well.

Different sources of light were used, ranging from a laser to white light simulating the solar spectrum. He said he would expect the reaction to work equally well using natural sunlight.

Once the nanoparticles are added and light applied, the water separates into hydrogen and oxygen almost immediately, producing twice as much hydrogen as oxygen, as expected from the 2:1 hydrogen to oxygen ratio in H2O water molecules, Bao said.

The experiment has potential as a source of renewable fuel, but at a solar-to-hydrogen efficiency rate of around 5 percent, the conversion rate is still too low to be commercially viable. Bao suggested a more feasible efficiency rate would be about 10 percent, meaning that 10 percent of the incident solar energy will be converted to hydrogen chemical energy by the process.

Other issues remain to be resolved, as well, including reducing costs and extending the lifespan of cobalt oxide nanoparticles, which the researchers found became deactivated after about an hour of reaction.

"It degrades too quickly," said Bao, who also has appointments in materials engineering and the Department of Chemistry.

The work, supported by the Welch Foundation, will lead to future research, he said, including the question of why cobalt oxide nanoparticles have such a short lifespan, and questions involving chemical and electronic properties of the material.

Extinct ancient ape did not walk like a human, study shows


According to a new study, led by University of Texas at Austin anthropologists Gabrielle A. Russo and Liza Shapiro, the 9- to 7-million-year-old ape from Italy did not, in fact, walk habitually on two legs.

The findings refute a long body of evidence, suggesting that Oreopithecus had the capabilities for bipedal (moving on two legs) walking.

The study, published in a forthcoming issue of the Journal of Human Evolution, confirms that anatomical features related to habitual upright, two-legged walking remain exclusively associated with humans and their fossil ancestors.

"Our findings offer new insight into the Oreopithecus locomotor debate," says Russo, who is currently a postdoctoral research fellow at Northeast Ohio Medical University. "While it's certainly possible that Oreopithecus walked on two legs to some extent, as apes are known to employ short bouts of this activity, an increasing amount of anatomical evidence clearly demonstrates that it didn't do so habitually."

As part of the study, the researchers analyzed the fossil ape to see whether it possessed lower spine anatomy consistent with bipedal walking. They compared measurements of its lumbar vertebrae (lower back) and sacrum (a triangular bone at the base of the spine) to those of modern humans, fossil hominins (extinct bipedal human ancestors), and a sample of mammals that commonly move around in trees, including apes, sloths and an extinct lemur.

The lower spine serves as a good basis for testing the habitual bipedal locomotion hypothesis because human lumbar vertebrae and sacra exhibit distinct features that facilitate the transmission of body weight for habitual bipedalism, says Russo.

According to the findings, the anatomy of Oreopithecus lumbar vertebrae and sacrum is unlike that of humans, and more similar to apes, indicating that it is incompatible with the functional demands of walking upright as a human does.

"The lower spine of humans is highly specialized for habitual bipedalism, and is therefore a key region for assessing whether this uniquely human form of locomotion was present in Oreopithecus," says Shapiro, a professor of anthropology. "Previous debate on the locomotor behavior of Oreopithecus had focused on the anatomy of the limbs and pelvis, but no one had reassessed the controversial claim that its lower back was human-like."

'Ardi' skull reveals links to human lineage -- did our pre-chimp ancestors walk upright?

Enlarge

New research led by ASU paleoanthropologist William Kimbel confirms Ardi's close evolutionary relationship to humans. Kimbel and his collaborators turned to the underside (or base) of a beautifully preserved partial cranium of Ardi. Their study revealed a pattern of similarity that links Ardi to Australopithecus and modern humans and but not to apes.

The research appears in the January 6, 2014, online edition of Proceedings of the National Academy of Science. Kimbel is director of the ASU Institute of Human Origins, a research center of the College of Liberal Arts and Sciences in the School of Human Evolution and Social Change. Joining ASU's Kimbel as co-authors are Gen Suwa (University of Tokyo Museum), Berhane Asfaw (Rift Valley Research Service, Addis Ababa), Yoel Rak (Tel Aviv University), and Tim White (University of California at Berkeley).

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

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

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

These shape differences affect the way the bones are arranged on the skull base such that it is fairly easy to tell apart even isolated fragments of ape and human basicrania.
Ardi's cranial base shows the distinguishing features that separate humans and Australopithecus from the apes. Kimbel's earlier research (with collaborator Rak) had shown that these human peculiarities were present in the earliest known Australopithecus skulls by 3.4 million years ago.
The new work expands the catalogue of anatomical similarities linking humans, Australopithecus, and Ardipithecus on the tree of life and shows that the human cranial base pattern is at least a million years older than Lucy's species, A. afarensis.

Paleoanthropologists generally fall into one of two camps on the cause of evolutionary changes in the human cranial base. Was it the adoption of upright posture and bipedality causing a shift in the poise of the head on the vertebral column? If so, does the humanlike cranial base of Ar. ramidus confirm postcranial evidence for partial bipedality in this species? Or, do the changes tell us about the shape of the brain (and of the base on which it sits), perhaps an early sign of brain reorganization in the human lineage? Both alternatives will need to be re-evaluated in light of the finding that Ardi does indeed appear to be more closely related to humans than to chimpanzees.

"The Ardi cranial base fills some important gaps in our understanding of human evolution above the neck," adds Kimbel. "But it opens up a host of new questions…just as it should!"


Faith or Science and-or BOTH

Faith or Science and-or BOTH

Like the monolith in the 1968 movie ‘2001 A Space Odyssey’, many people today regard science as a shining, monolithic spire of truth rising above the landscape of human ignorance and superstition. Because of that, I often talk with people who fully apply all their critical thinking skills, and their full Internet-searching abilities, to see if they can discover a weak link in evidence for the truth of Christian beliefs. However, they have a complete, unquestioning faith in science. That makes for one of the great scientific mysteries of the ages. Moreover, they come to this ‘faith’ by reading and repeating what the establishment says they should believe and this is done typically by publishing a series of narrowly focused technical papers based on their own experimental research which generally does little to advance the subject matter. And what is worse, they are not explaining the preexisting evidence in a new or more coherent way.

As a software developer who has spent the last 20 years of my career working within the medical, physical therapy, insurance and oil and gas industries, I consider myself knowledgeable in various aspects of science and the deductive scientific method. I have become increasingly appalled and even shocked at what passes for science in a wide variety of disciplines. It has become a mix of good science, bad science, creative story-telling, science fiction (the multiverse), scientism (atheism dressed up as science), citation-bias, huge media announcements followed by quiet retractions, massaging the data, exaggeration for funding purposes, and outright fraud all rolled up together. In some disciplines, the problem has become so rampant that the “good science” part is drowning in a mess of everything else. I will cover each of the above problems in another article.

One must first understand what constitutes good science if you are going to criticize it. Good science, requires very little faith and should be trusted as far as we can trust anything that human beings try to do well.

The heart of good science is the scientific method. I have criticized Wikipedia on my blogs many times (it is very liberal and left-leaning). On this subject, though it has a good description of the scientific method. First, on the basis of a question, observation, or known laws of physics, draft a possible answer, explanation or “hypothesis.” Next, advance a falsifiable prediction on the basis of the hypothesis. Then, experimentally test the prediction. If the prediction is falsified, modify or abandon the hypothesis. If it is verified, the hypothesis is strengthened and lives to see another day.

Modify or abandon the hypothesis seems to be a major problem in academia today. It is part of the ‘political correctness’ running rampant today in society and in ‘higher education’. Nobody is wrong anymore, and certainly do not wish to admit that they were wrong, or had a wrong idea, or spent time researching something that was not productive and goodness gracious wasted money from a governmental grant.

Avoid a double standard in how you apply your critical thinking skills scientific claims are not above question. When you see a scientific claim, see if there is actually experimental verification of a falsifiable prediction. You might be surprised at how often a falsifiable prediction is not tested or even mentioned. Look for the use of creative stories, or words like “suggests” or “may have” to make up for a lack of substance. Investigate whether evidence that does not support the hypothesis or prediction is being ignored.

Above all, have a clear understanding of the scientific method and consider how well each claim adhered to that method. Coming up, I will look at the specific types of problems listed in the second paragraph, with examples, of corruption in 21st-century science that are in contrast to good science and the scientific method.

Why am I doing this? I will be showing, eventually, that we can come to conclusions about our past and our future using a variety of scientific methods using both inductive and abductive (a form of logical inference which goes from an observation to a theory which accounts for the observation, ideally seeking to find the simplest and most likely explanation) reasoning.



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