Poetry Day / The Sound of China Breaking

The Sound of China Breaking

 

 

 

The dogs scramble over slabs of sandstone

that have toppled from an outcrop on the far side of the canyon;

strewn about by gravity, as if a cave woman had set out her dishes to dry.

So I toss a rock to get their attention, and when it hits

the ground at their feet, I hear the sound of china breaking.

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At Last / Escape from being snowbound

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I was about to go seriously bonkers from claustrophobia – the truck and parking area were knee deep in snow. Dug myself out this morning and drove south onto the plateau. Brilliant wind-whipped new drifts along my favorite snow fence, and blue, blue double blue sky. Freedom…until the next storm…

Childhood Obsession / Charles 1st by van Dyck

My mother bought a book: one of those huge volumes titled 100 Favorite Paintings. Before I learned to read, it was an “education” in art and I fixated on one painting – I still find it beautiful and fascinating. .

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Anthony van Dyck, 1635 / “Charles 1 at the Hunt”

Sir Anthony van Dyck was a Flemish Baroque artist who became the leading court painter in England, after enjoying great success in Italy and Flanders.

“All art Lies.”

I had no idea who these people were, but it was to be my first encounter with power of images and the people who painted them. After I learned to read, the sad story of “the beautiful man in beautiful boots” taught me that “civilized” people use torture and  executions (beheadings) to “solve their problems.” I found this terrifying. 

Study for a painting of Charles 1 - van Dyck

Study for a painting of Charles 1 – van Dyck

BBC Archives Charles I (1600 – 1649) 

Charles I was king of England, Scotland and Ireland, whose conflicts with parliament led to civil war and his eventual execution.

Charles I was born in Fife on 19 November 1600, the second son of James VI of Scotland and Anne of Denmark. On the death of Elizabeth I in 1603 James became king of England and Ireland. Charles’s popular older brother Henry, whom he adored, died in 1612 leaving Charles as heir, and in 1625 he became king. Three months after his accession he married Henrietta Maria of France. They had a happy marriage and left five surviving children.

Charles’s reign began with an unpopular friendship with George Villiers, Duke of Buckingham, who used his influence against the wishes of other nobility. Buckingham was assassinated in 1628. There was ongoing tension with parliament over money – made worse by the costs of war abroad. In addition, Charles favoured a High Anglican form of worship, and his wife was Catholic – both made many of his subjects suspicious, particularly the Puritans. Charles dissolved parliament three times between 1625 and 1629. In 1629, he dismissed parliament and resolved to rule alone. This forced him to raise revenue by non-parliamentary means which made him increasingly unpopular. At the same time, there was a crackdown on Puritans and Catholics and many emigrated to the American colonies.

Unrest in Scotland – because Charles attempted to force a new prayer book on the country – put an end to his personal rule. He was forced to call parliament to obtain funds to fight the Scots. In November 1641, tensions were raised even further with disagreements over who should command an army to suppress an uprising in Ireland. Charles attempted to have five members of parliament arrested and in August 1642, raised the royal standard at Nottingham. Civil war began.

The Royalists were defeated in 1645-1646 by a combination of parliament’s alliance with the Scots and the formation of the New Model Army. In 1646, Charles surrendered to the Scots, who handed him over to parliament. He escaped to the Isle of Wight in 1647 and encouraged discontented Scots to invade. This ‘Second Civil War’ was over within a year with another royalist defeat by Parliamentarian general Oliver Cromwell. Convinced that there would never be peace while the king lived, a rump of radical MPs, including Cromwell, put him on trial for treason. He was found guilty and executed on 30 January 1649 outside the Banqueting House on Whitehall, London.

 

 

Artificial Evolution Videos / Seeing is better than believing!

Published on Nov 25, 2013

We present a control method for simulated bipeds, in which natural gaits are discovered through optimization. No motion capture or key frame animation was used in any of the results. For more information, see http://goatstream.com/research/papers…

 

Published on Jun 30, 2016

Accompanying video for: F. Corucci, N. Cheney, H. Lipson, C. Laschi and J. Bongard, “Evolving swimming soft-bodied creatures”
The Fifteenth International Conference on the Synthesis and Simulation of Living Systems (ALIFE XV) – Late Breaking Abstract

Paper: http://sssa.bioroboticsinstitute.it/s…
See also our growing soft robots exploiting morphological computation: https://youtu.be/Cw2SwPNwcfM

More on:
http://sssa.bioroboticsinstitute.it/u…
http://www.meclab.org/

 

Published on Jun 29, 2014

The research field of evolutionary robotics abstracts some of the major themes in biological evolution (heritable traits, genetic variation, and competition for scarce resources) as tools to allow computers to generate new and interesting virtual creatures. One of the recent themes in this field is towards more embodied robots (those that produce interesting behavior through the design of their bodies, as well as their brains). Here, we build on previous work evolving soft robots to demonstrate the low level embodiment of electrical signals passing information through muscle tissue. Through this work we attempt bridge the divide between embodied cognition and abstracted artificial neural networks. We hope you find the video interesting and entertaining!

This video accompanies the following paper:
Cheney, N., Clune, J., Lipson, H. (2014) “Evolved Electrophysiological Soft Robots”. Proceedings of Artifical Life 14: The Fourteenth International Conference on the Simulation and Synthesis of Living Systems (ALife14). MIT Press.
(pdf: http://creativemachines.cornell.edu/s…)

Paleontology Online / Fossil Focus: Encephalization in bipedal apes

A simple review of the “story” of “encephalized bipedal apes” as paleontologists see it.

Paleontology is not to be confused with anthropology: Paleontology is traditionally divided into various subdisciplines: Micropaleontology: Study of generally microscopic fossils, regardless of the group to which they belong. Paleobotany: Study of fossil plants; traditionally includes the study of fossil algae and fungi in addition to land plants. Palynology: Study of pollen and spores, both living and fossil, produced by land plants and protists. Invertebrate Paleontology: Study of invertebrate animal fossils, such as mollusks, echinoderms, and others. Vertebrate Paleontology: Study of vertebrate fossils, from primitive fishes to mammals. Human Paleontology (Paleoanthropology): The study of prehistoric human and proto-human fossils. Taphonomy: Study of the processes of decay, preservation, and the formation of fossils in general. Ichnology: Study of fossil tracks, trails, and footprints. Paleoecology: Study of the ecology and climate of the past, as revealed both by fossils and by other methods.

In short, paleontology is the study of what fossils tell us about the ecologies of the past, about evolution, and about our place, as humans, in the world. Paleontology incorporates knowledge from biology, geology, ecology, anthropology, archaeology, and even computer science to understand the processes that have led to the origination and eventual destruction of the different types of organisms since life arose.

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Fossil Focus: Encephalized bipedal apes
paleontologyonline.com / by Holly M. Dunsworth

Humans would not have evolved if the ancestors of the African great apes had not. The ape fossil record begins 23 million years ago with the earliest putative apes, including Morotopithecus and Proconsul (Figure 1), from sites in East Africa, followed by many others throughout Africa, Europe and Asia. Although this record is fairly rich, it has done no better than DNA-based estimates at helping researchers to determine how living apes are related. Genetic studies estimate that gorillas split off from other apes about 9 million to 8 million years ago, and that the ancestors of bonobos and chimpanzees began evolving separately from the ancestors of humans 7 million to 6 million years ago.

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Figure 1 – Right lateral (a) and front (b) views of the fossilized teeth and bones of the skull of the early ape Proconsul (museum catalogue no. KNM-RU 7290). Mary Leakey discovered this specimen, well-known for its remarkable preservation, on Rusinga Island, Kenya, in 1948. Images are not to scale with one another. Credit: Alan Walker.

Comparative anatomy, physiology, behaviour and genetics provide enough evidence for us to understand that humans are more closely related to chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) than to any other species, and vice versa. But the fossil record of hominins (species more closely related to humans than to chimps) preserves snapshots of the how the evolutionary path of our lineage differs from theirs. Unfortunately, the fossil record of chimpanzee and bonobo evolution is small enough to fit into a coat pocket, but the fossil evidence for human evolution is far greater: there are hundreds of specimens, including many nearly complete skeletons and many well-preserved skulls. Although the hominin fossil record is dominated by durable teeth — which reveal diet, age of death, pace of growth and much more — here we will focus, briefly, on the tales of two other significant human traits that are well documented in the hominin lineage: our big brains and our bipedal bodies.

Of course, humans are not the only animals to have extremely large brains for their body sizes (to be highly encephalized). Witness the octopus and the squid — members of the cephalopod class — and, among mammals, the toothed whales, or odontocetes. The African great apes also have large brains, but humans, as the sole surviving hominin, are considered to be the most encephalized. Nor are humans the only animals to walk habitually on two legs. Birds and many of their extinct dinosaur relatives are just some of the many bipeds that have roamed, and continue to roam, Earth. But although many primates, especially the African great apes, frequently walk on their hind limbs — particularly when carrying objects, while moving about the trees and during bouts of threatening or playing — humans are the only ones to be dedicated to this mode of locomotion.

The first five million years or so of the hominin fossil record (from about 7 million to 2 million years ago) are dominated by the gradual appearance of bipedal characteristics in the skeleton. It was not until the last 2 million years — by which point most of the skeleton, apart from the cranium (or top part of the skull), resembled that of a modern human — that encephalization took off.

Evolving bipedalism (Late MiocenePliocene, sub-Saharan Africa)

Compared with other apes — for example, gorillas (Figure 2), which climb and hang in trees and walk on all fours using their manual knuckles — the human skeleton’s anatomy reflects adaptations for upright walking and running. The human pelvis is modified so that the ilia (the blades) are bowl-shaped and curved around to the sides of the body, rearranging the muscles for balance during the single-support phase (i.e. when only one foot is on the ground) that dominates the time we spend walking. The spine is curved at the lumbar (lower back) and cervical (neck) regions, balancing our skeletons. Human legs are longer than our arms and long for our overall size compared to apes, helping to make us better travellers. Our hip joints are large and sturdy, because only two limbs bear our weight. Our knees are also large and reveal the angle of our femur (thigh bone), bringing the knee and the foot directly under our centre of gravity with every step. Our ankles and heels are rigid bony blocks, and the arches of our feet help to store and release energy with each stride. Our hallux (big toe) is not able to grasp like the thumb-like toe of many apes, but instead lines up with the other digits (all short toes) and plays a role in forcefully pushing off from the ground (‘toe-off’) at the end of each step during walking and running.

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Figure 2 — Drawings of a human and gorilla skeleton. Humans did not evolve from the African great apes (gorillas, chimpanzees and bonobos), but the anatomies of our common ancestors are thought to be more like those apes than like us. The further back we go in the hominin fossil record, the less human-like and the more ape-like they appear. http://en.wikipedia.org/wiki/File:Primatenskelett-drawing.cjpg

The absolute best evidence for bipedal behaviour in the fossil record comes from footprints; they are direct impressions of that behaviour, requiring absolutely no inference from the shape of fossilized skeletons. And in Laetoli, Tanzania, there are wonderfully preserved 3.6-million-year-old tracks left by at least two bipedal hominins. They are not exactly like the prints that humans make today, but they lack an ape-like, divergent big toe and are not accompanied by any hand or knuckle prints.

At the time the tracks were laid down there is dental and bony fossil evidence in East Africa for Australopithecus afarensis. This is the species of the famous partial skeleton known as Lucy, discovered in the 1970s. Because A. afarensis skeletal morphology indicates that it walked upright, the Laetoli trackways are credited to the species. However, just whether A. afarensis walked upright all the time or only some of the time, and how much its bipedalism resembled modern human bipedalism, is still debated because A. afarensis did not have all the features that we associate with bipedalism in ourselves. This also goes for related australopiths discovered in South Africa, Australopithecus africanus and Australopithicus sediba. The australopith pelvis is not as bowl-shaped as ours; the legs are short and the arms relatively long; the toes are long and slightly curved; and the configuration of the tarsals, or foot bones, causes debate over whether the foot had an arch and whether australopiths tended to walk ‘pigeon-toed’. Making interpretation more difficult are new finds such as a foot from the site of Burtele in Ethiopia, which is near to and from around the same time as sites that produce A. afarensis fossils. The Burtele foot has some anatomy that suggests bipedalism, but also has an ape-like divergent hallux. It’s too much variation to include in a single species and, because of the hallux, cannot possibly belong to the hominins that left footprints at Laetoli. Despite these intriguing problems, it is clear that bipedalism, in whatever form it came, had hit its stride during Australopithecus times.

(Bones of Contention): For many palaeoanthropologists, the presence of bipedalism is the standard way to identify a hominin, meaning to decide that a fossil is a member of the human family tree, not another ape’s. This is the main reason that australopiths are labelled as hominins. But australopith species are known to have lived only from a little over 4 million years ago to roughly 2 million years ago, which does not go far enough back to match DNA-based estimates of when hominins diverged from chimps and bonobos, around 7 million to 6 million years ago. There are fossils older than the australopiths that look tantalizingly like hominins, but not completely. They belong to three genera: Sahelanthropus (from about 7 million years ago in Chad); Orrorin (from about 6 million years ago in Kenya); and Ardipithecus (from between 5.8 million and 4.4 million years ago in Ethiopia). Tooth shape and indications that they walked on two legs mean that all three of these genera have been placed at the base of the hominin tree by some researchers. However, other researchers disagree, in large part because of debate about how these animals moved. Much more is known for Ardipithecus than the other two genera. As predicted for an early hominin, its skeleton has so many primitive and/or non-human-like features that it is not completely clear whether it was bipedal, and also whether it was an ancestor to australopiths (although its teeth suggest that it was).

For the foreseeable future, there will be debate about these early hominins and their behaviour: whether or not they walked on two feet regularly; they were doing so using a non-modern skeleton, so it is difficult to tell exactly how their movement worked. Bipedalism does not require a modern human skeleton, as shown by the Laetoli prints. However, the only way that researchers can work out how hominin fossils moved is to look at the observed anatomy and behaviour of the one surviving bipedal hominin species: modern humans. The traits that we associate with bipedalism in our own muscles and skeletons appeared slowly over the first 5 million years of hominin evolution, so those 5 million years are best described as showing a slow shift to habitual bipedalism.

There seems to have been an ecological shift to accompany the change in locomotion. Evidence, particularly from the chemistry of tooth enamel, suggests that australopiths were starting to eat lots of grasses and related plants, whereas other apes eat mostly fruits, leaves and nuts. This shift in dietary ecology supports the idea that the australopiths or their ancestors had moved out of the trees to look for food on the ground, consistent with a modified take on the ‘savannah hypothesis’ in which, during the Pliocene epoch (5.3 million to 2.6 million years ago), hominins evolved under pressure to be able to find food in the relatively new grasslands of East and South Africa. Instead of terrestrial bipedalism originating with scavenging and hunting behaviours, as in the usual savannah hypothesis, perhaps it began with a mainly herbivorous phase.

Another traditional scenario, suggested by Charles Darwin, is that bipedalism arose to free the hands for making and using tools, carrying tools and food, and throwing objects while foraging or socializing. Unfortunately for this hypothesis, there are few tools preserved from 7 million to 2.5 million years ago. If we accept that Ardipithecus, Orrorin and Sahelanthropus are early hominins, then we must say that bipedalism originated in wooded environments because that is how their environments have been reconstructed. The first hominins could have lived in trees as much or even more than extant great apes do now, and evolved bipedal locomotion there.

Evolving encephalization (Pleistocene, Old World)

Since the late Pliocene — when the hominin locomotor anatomy began to be familiarly human — hominin brains have tripled in size. Given that it is impossible to re-run evolution to find out whether our extreme encephalization could have evolved if we had not first become bipedal, we are all but forced (why? other highly encephalized species are not bipedal) to assume that bipedalism was a prerequisite.

There are three main hypotheses to explain hominin encephalization. The first is a technological scenario. Non-human primates that make and use tools have the largest brains and the most complex behaviours. Once the forelimbs are no longer necessary for locomotion, as in hapitually bipedal hominins, they can be used for more complex technology, more regularly, which in turn selects for further encephalization. This hypothesis is supported by the emergence of the first encephalized hominins — Homo habilis, the earliest members of our own genus — roughly coinciding with the earliest fairly regular appearance of crude stone tools, starting around 2.5 million years ago. These tools have been dubbed the Oldowan tradition, after Olduvai Gorge in Tanzania, where they were first discovered.

The second scenario to explain encephalization is ecological. Again, primates with complex ecological behaviours tend to have large brains. Once hominin bodies committed to bipedalism, they were suited for scavenging and hunting animal prey. Predicted consequences of this shift are borne out in the fossil record for Homo erectus, a hominin with half or more of the modern-human brain size, which emerged about 1.8 million years ago. The skeleton of H. erectus approaches modern proportions and the hominin’s anatomy seems to be built for short bursts of speed and long-distance travel. The diet included high-quality animal protein and fat for feeding a larger brain. H. erectus had a body size similar to that of modern humans (with lots of diversity), and it is the first hominin found outside Africa. Almost as soon as it originated in Africa, H. erectus dispersed across the continent and into Europe, central Asia and southeast Asia. (Why? Because it could, thanks to the changes above)

Much of the evidence for the ecological scenario is rooted in the discovery in the 1980s of a well-preserved H. erectus skeleton in Nariokotome in Kenya (Figure 3). It is not clear how large a role meat played in our ancestors’ diets, because the record is biased toward preserving bones of devoured prey over remains of devoured vegetation. However, there is no denying that an ecological shift occurred in the early Pleistocene, with H. erectus developing a more diverse diet and habitat and becoming more skilled at hunting. That shift must have included new requirements of the brain. There are hints at sites in Africa that H. erectus was able to control fire during the early Pleistocene, but the first reliable evidence of fire use does not appear until 800,000 years ago at a H. erectus site in Israel. Even then, there is no preserved evidence for regular fire use until around 400,000 years ago, when H. erectus was largely gone (or evolved into more modern) and more modern hominins existed. Scavenging, hunting, control and use of fire for cooking, living in diverse habitats in diverse climates and increasingly complex stone-tool manufacture require a larger, more complex brain. (These behaviors are possible due to a more complex brain)

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Figure 3 — Nearly complete skeleton of the Nariokotome Boy (also known as Turkana Boy; museum catalogue no. KNM-WT 15000). This juvenile Homo erectus was discovered on the western side of Lake Turkana, Kenya, and dates to around 1.5 million to 1.6 million years ago. Credit: Alan Walker.

The third major hypothesis for encephalization is social. As hominins became skilled hunters and gatherers, they relied more and more on cooperative foraging behaviours, and being able to navigate social networks across time and space became increasingly adaptive behaviour. Once complex speech and language arrived, there would be new demands on the brain, not only for these behaviours, but also for the new cultural, cooperative environment that language created. Brain size, and especially the ratio of brain to body size, reached modern proportions by 500,000 years ago, with ‘archaic’ or early Homo sapiens, so social selective pressures would have contributed both to reaching modern brain sizes and to maintaining it through to the emergence of modern Homo sapiens – represented by skeletons dating to 195,000 years ago at Omo in Ethiopia. The same social conditions might have led to encephalization among Neanderthals, Homo neanderthalensis, which lived roughly 300,000 to 30,000 years ago in Europe, the Middle East, and Eurasia. Neanderthal encephalization was comparable to ours and maybe slightly greater. There is an ongoing argument among researchers as to whether Neanderthals were a separate species, called Homo neanderthalensis, or a subspecies of Homo sapiens.

The technological, ecological and social pressures, requirements or demands could have worked both together and at different times throughout the Pleistocene epoch to the present and over many hominin generations. These evolutionary pressures would contribute to the more or less sustained reproductive success of hominins with slightly larger brains. And the fossil and archaeological records suggest that technology would have had the earliest effect, followed by the shift in ecology, and then sociality. These are some of the most mainstream hypotheses for encephalization and they implicitly or explicitly depend on bipedalism evolving before encephalization.

From bipedal ape to encephalized bipedal ape

We assume that some population of australopiths gave rise to the first members of the human genus, Homo. The earliest known Homo is australopith-like in anatomy but has a few differences, mainly its ever-so-slightly larger cranial capacity (a good proxy for brain size during life). Some researchers have argued that australopiths have marked encephalization, but others think that only early Homo had more encephalization than living apes. This debate will continue until more fossils are found that have indicators of both brain and body size for comparison. Until then, most researchers are comfortable beginning the brain-size story with Homo. It probably helps that the earliest stone tools on record and the earliest evidence for animal carcasses processed with those tools are found during the early Pleistocene, in early Homo times.

It is unclear when the hominin ecological shift to being stone-tool-making, meat-eating apes began. If the behaviour was common by H. erectus times, it should have started earlier. There is tantalizing evidence to suggest just this: the first known stone tools are from Gona in Ethiopia at about 2.6 million years ago, when only australopiths are thought to have been present. At 2.5 million years ago, when there were still just australopiths present, there are bones marked with cuts made by stone tools at nearby Bouri in Ethiopia. A few years ago, another site in Dikika, Ethiopia, dated to 3.4 million years ago (during A. afarensis times), produced what appear to be bones marked by stone-tool cuts. If this evidence is interpreted correctly, it is consistent with the dawn of an ecological shift leading up to the more conspicuous evidence with Homo erectus.

Considering the evolution of these two major traits from an energetic standpoint, bipedalism may have been a prerequisite for encephalization. Bipedal locomotion appears to expend less energy than walking terrestrially as a great ape and that freed-up energy could have been reallocated to brain growth. And, of course, with greater technological, ecological and social intelligence aiding human foragers the resulting increase in food quality and quantity provided the energy for growing a large hominin brain.  Pound for pound, brains are metabolically expensive so even something as seemingly straightforward as natural selection for a large intelligent brain must be a complex story.

Palaeoanthropologists continue to strive for better methods of understanding behaviour from bones and describing the anatomical, ecological and environmental contexts of the origins and evolution of bipedalism and encephalization. New fossil, archaeological and geological discoveries will be crucial for solving these puzzles in palaeoanthropology.

Suggested reading

Peer-reviewed articles about human and primate evolution.

All the articles published in Science about the discovery of Australopithecus sediba are here.

For comprehensive estimates of lineage splitting times, see Time Tree: The scale of life.

For introductory information about human evolution see http://humanorigins.si.edu/ & http://www.pbs.org/wgbh/evolution/humans/index.html

 

 

“Other” Bipedal Animals / What makes “us” different?

Comment: Two and a half years of blogging about Asperger’s (the myth, the so-called disorder and  developmental disability – and the personality type), has led to an ever-expanding multitude of topics that deal with the question of “what differentiates” Homo sapiens as a species, and “just who” qualifies to represent “our species” (the social version). After long consideration and study, I’ve come to a tentative conclusion: Bipedalism is the key to “who we are”. The “rest of our story” follows this anatomical event.

However, in contrast to our self-centered history of life, with “man” at the evolutionary pinnacle of inevitable superiority, birds constitute the overwhelming majority of bipedal animals – Homo sapiens, and our tiny group of related apes, are not at all the “typical” or sole evolutionary experiment with this form of locomotion.

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Bipedal success: 9700 living species of birds vs. ONE species of bipedal ape.

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Wiley Online Library / Journal of Anatomy (full article is available, but link(s) fail)

Bipedal animals, and their differences from humans

Professor R. McN. Alexander, School of Biology, University of Leeds, Leeds UK.

Abstract

Humans, birds and (occasionally) apes walk bipedally. Humans, birds, many lizards and (at their highest speeds) cockroaches run bipedally. Kangaroos, some rodents and many birds hop bipedally, and jerboas and crows use a skipping gait. This paper deals only with walking and running bipeds. Chimpanzees walk with their knees bent and their backs sloping forward. Most birds walk and run with their backs and femurs sloping at small angles to the horizontal, and with their knees bent. These differences from humans make meaningful comparisons of stride length, duty factor, etc., difficult, even with the aid of dimensionless parameters that would take account of size differences, if dynamic similarity were preserved. Lizards and cockroaches use wide trackways. Humans exert a two-peaked pattern of force on the ground when walking, and an essentially single-peaked pattern when running. The patterns of force exerted by apes and birds are never as markedly two-peaked as in fast human walking. Comparisons with quadrupedal mammals of the same body mass show that human walking is relatively economical of metabolic energy, and human running is expensive. Bipedal locomotion is remarkably economical for wading birds, and expensive for geese and penguins.

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Mechanisms for the acquisition of habitual bipedality: are there biomechanical reasons for the acquisition of upright bipedal posture?

Preuschoft H1 / 1Ruhr-University, Bochum, Germany.

 

Abstract

Morphology and biomechanics are linked by causal morphogenesis (‘Wolff’s law’) and the interplay of mutations and selection (Darwin’s ‘survival of the fittest’). Thus shape-based selective pressures can be determined. In both cases we need to know which biomechanical factors lead to skeletal adaptation, and which ones exert selective pressures on body shape. Each bone must be able to sustain the greatest regularly occurring loads. Smaller loads are unlikely to lead to adaptation of morphology.

The highest loads occur primarily in posture and locomotion, simply because of the effect of body weight (or its multiple). In the skull, however, it is biting and chewing that result in the greatest loads. Body shape adapted for an arboreal lifestyle also smooths the way towards bipedality.

Hindlimb dominance, length of the limbs in relation to the axial skeleton, grasping hands and feet, mass distribution (especially of the limb segments), thoracic shape, rib curvatures, and the position of the centre of gravity are the adaptations to arboreality that also pre-adapt for bipedality. (That is, the transition from tree living to ground dwelling is not “bizarre, strange, nor incomprehensible”; nor does it require “supernatural” intervention)

Five divergent locomotor /  morphological types have evolved from this base: arm-swinging in gibbons, forelimb-dominated slow climbing in orangutans, quadrupedalism/climbing in the African apes, an unknown mix of climbing and bipedal walking in australopithecines, and the remarkably endurant bipedal walking of humans. All other apes are also facultative bipeds,but it is the biomechanical characteristics of bipedalism in orangutans, the most arboreal great ape, which is closest to that in humans.

If not evolutionary accident, what selective factor can explain why two forms adopted bipedality? Most authors tend to connect bipedal locomotion with some aspect of progressively increasing distance between trees because of climatic changes. More precise factors, in accordance with biomechanical requirements, include stone-throwing, thermoregulation or wading in shallow water. Once bipedality has been acquired, development of typical human morphology can readily be explained as adaptations for energy saving over long distances. A paper in this volume shows that load-carrying ability was enhanced from australopithecines to Homo ergaster (early African H. erectus), supporting an earlier proposition that load-carrying was an essential factor in human evolution.

Primitive Technology / Intuitive Physics – Atlatl

Comment: Interest in the atlatl has been revived by the growing “primitive hunting technology community” which is related to the “off-grid” survival movement which embraces sustainable methods for procuring food without dependence on high-tech weapons.

As kids, most of us were briefly introduced to the atlatl in social studies class, as part of “Human Cultural History” – a thin survey about technical progress and foods, farming, the advent of cities and the titanic architecture of famous ancient empires.

The atlatl stuck out like a sore thumb: stone, wood and mud construction seemed to be pretty obvious steps for humans to “figure out”, but how did someone “come up with” the spear-launcher, which in my child mind appeared to be a much more sophisticated invention, and a leap into a future of human innovation. My father was an engineer, so  I was aware of the mathematics, tables, slide-rule calculations and testing and revision required for him to design mechanical gadgets and components; so how did “cave men” create weapons and tools, without these technical advantages? It’s a question that to this day produces varied explanations and arguments (many preposterous) that deal with the fundamental concept of “being and becoming” human.

Of course, I have my opinions, based in “visual thinking” as the capable manipulation of “intuitive physics” without formal math and theory-based brain processing.

From OUTDOOR HUB

Missouri Hunter Harvests 15-point Buck with Atlatl

Predating the bow and arrow, atlatls are one of the oldest primitive weapons still in use. The dart (a 4′-6′ projectile, much like an arrow) is placed on a launcher—the atlatl itself—that has a socket at the rear to temporarily hold the dart. The hunter propels the launcher forward and the dart flies like a spear. The atlatl allows the dart to be thrown much faster than what could be achieved by hand, and launched darts could go as fast as 100 miles per hour.

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Contemporary atlatls by Jim Fisher

How Joints Use Leverage (And Why That’s Awesome)

http://reembody.me/how-joints-use-leverage/ June 28, 2013 by chuck

atlatl: (link to Wikipedia)

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Specifically, the handle in which the spear is cupped is an atlatl. Humans have been using devices like this for hunting and warfare for around 30,000 years. “Atlatl” is the Aztec terminology, but it has been called “amentum” by the Romans; “woomera” by Australian Aborigines, and  “ankule” by the Greeks.

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Let’s be clear: it’s essentially a stick. But this stick, employed just so, dramatically increases the power and accuracy of a projectile. Modern versions made of carbon fiber and aluminum, can launch a spear 850 feet. By comparison, the record distance for the javelin throw is 321 feet.

Those extra 529 feet can be accounted for through the beauty and elegance of Sir Isaac Newton’s Laws of Motion. A  throwing spear has a metal or stone tip, shaped and sharpened to cut and pierce. This shaped point, by virtue of its material, is more massive (m) than the butt-end of the spear. Consequently, the same force (F) applied to both ends would cause the butt-end to accelerate (a) faster. F=ma, says Newton.

Picture this: a swing of the atlatl causes the butt-end of the spear to accelerate. The more-massive pointy end resists acceleration, building speed more slowly than the less-massive butt-end. With the back end moving faster than the front, the spear bows. (flexes to become an arc shape)

That bowing action (flex) converts the kinetic energy of the swing into potential energy stored in the tensile fibers of the spear’s shaft. At the last moment of contact between spear and spear thrower, the shaft unbows, (straightens) converting its stored, potential energy back to kinetic energy, and adding it to the overall acceleration of the spear.

It’s just a stick! How did humans 20,000 years before the invention of agriculture come up with such an ingenious little device?

Most of the joints in the body “exploit” the same principle of physics.

Did anyone happen to notice the Greek term for these spear throwers? Ankule. If you’re thinking that sounds suspiciously like ankle, you’re right, and it’s not an accident. Most of the force that accelerates your running stride is “free energy” due to simple physics (levers) – the arrangement of “bone sticks” that make up your skeleton.

 

Female Asperger Wedding Photo / Mother Disapproves

I told my mother that I wouldn’t show up in a regular wedding dress. I found this lovely gold and white striped Turkish coat at a second hand store. She threw a fit.

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