(01) australopithecus afarensis | the smithsonianaustralopithecus means ‘southern ape’ and was...

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(01) Australopithecus afarensis | The SmithsonianInstitution's Human Origins Program

Australopithecus afarensis

Nickname: Nickname: Lucy's species

Where Lived: Where Lived: Eastern Africa (Ethiopia, Kenya,Tanzania)

When Lived: When Lived: Between about 3.85 and 2.95million years ago

Australopithecus afarensis is one of the longest-lived and best-known early human species—paleoanthropologists have uncovered remainsfrom more than 300 individuals! Found between3.85 and 2.95 million years ago in Eastern Africa(Ethiopia, Kenya, Tanzania), this species survived

for more than 900,000 years, which is over four times as long as our own species has beenaround. It is best known from the sites of Hadar, Ethiopia (‘Lucy’, AL 288-1 and the 'FirstFamily', AL 333); Dikika, Ethiopia (Dikika ‘child’ skeleton); and Laetoli (fossils of thisspecies plus the oldest documented bipedal footprint trails).

Similar to chimpanzees, Au. afarensis children grew rapidly after birth and reachedadulthood earlier than modern humans. This meant Au. afarensis had a shorter period ofgrowing up than modern humans have today, leaving them less time for parental guidanceand socialization during childhood.

http://humanorigins.si.edu/evidence/human-fossils/species/australopithecus-afarensis



Au. afarensis had both ape and human characteristics: members of this species had apelikeface proportions (a at nose, a strongly projecting lower jaw) and braincase (with a smallbrain, usually less than 500 cubic centimeters -- about 1/3 the size of a modern humanbrain), and long, strong arms with curved ngers adapted for climbing trees. They also hadsmall canine teeth like all other early humans, and a body that stood on two legs andregularly walked upright. Their adaptations for living both in the trees and on the groundhelped them survive for almost a million years as climate and environments changed.

Year of Discovery: Year of Discovery: 1974

Height: Height: Males: average 4 ft 11 in (151 cm); Females: average 3 ft 5 in (105 cm)

Weight: Weight: Males: average 92 lbs (42 kg) ; Females: average 64 lbs (29 kg)

We don’t know everything about our early ancestors—but we keep learning more!Paleoanthropologists are constantly in the eld, excavating new areas, usinggroundbreaking technology, and continually lling in some of the gaps about ourunderstanding of human evolution.

Below are some of the still unanswered questions about Au. afarensis that may beanswered with future discoveries:

A fossil similar to Au. afarensis and dating to 3.5 million years ago has been found inChad—did this species extend so far into central Africa? We know Au. afarensis were capable of walking upright on two legs, but they wouldhave walked di erently than modern humans do today; so, what did their bipedallocomotion look like? Did Au. afarensis usually walk upright like modern humans, or did they spend moretime climbing trees like other living African apes?




The species Au. afarensis existed through a period of environmental uctuation yetshowed no adaptations to the changing environment—why? Was it because theywere able to migrate to where their usual food sources were located? Or were theirfood sources somehow unaffected? Au. afarensis shows strong sexual dimorphism in that the body sizes between malesand females are quite di erent; however, sexual dimorphism in other primates isusually characterized by size di erences in bodies and teeth. Fossil evidence showsthat male Au. afarensis individuals had canine teeth comparable in size to those offemales. Did male dominance in Au. afarensis individuals not include the need tobear large canine teeth, as it does in many other male primates? The teeth and jaw of Au. afarensis are robust enough to chew hard foods, but dentalmicrowear studies show Au. afarensis individuals ate soft foods like plants and fruitinstead. While most scientists think that Au. afarensis ate hard, brittle foods duringtough times when vegetation was not easily found, further microwear studies showthat eating hard foods did not coincide with dry seasons of little vegetation. So howdo properties of Au. afarensis teeth relate to their diet?

How They Survived: How They Survived: Au. afarensis had mainly a plant-based diet, including leaves, fruit, seeds, roots, nuts, andinsects… and probably the occasional small vertebrates, like lizards.

How do we know what How do we know what Au. afarensisAu. afarensis ate? ate?Paleoanthropologists can tell what Au. afarensis ate from looking at the remains of theirteeth. Dental microwear studies indicate they ate soft, sugar-rich fruits, but their tooth sizeand shape suggest that they could have also eaten hard, brittle foods too – probably as‘fallback’ foods during seasons when fruits were not available.

Evolutionary Tree Information: Evolutionary Tree Information: This species may be a direct descendant of Au. anamensis and may be ancestral to laterspecies of Paranthropus, Australopithecus, and Homo.



(02) Australopithecus afarensis - Australian Museum

This species is one of the best known of our ancestors.

Australopithecus afarensis skull Photographer: Stuart Humphreys © Australian Museum

This species is one of the best known of our ancestors due to a number of major discoveriesincluding a set of fossil footprints and a fairly complete fossil skeleton of a femalenicknamed 'Lucy'.

Background of discoveryAge

This species lived between 3.9 and 2.8 million years ago.

What the name means

Australopithecus means ‘southern ape’ and was originally developed for a species found inSouth Africa. This is the genus or group name and several closely related species now sharethis name.

The word afarensis is based on the location where some of the rst fossils for this specieswere discovered – the Afar Depression in Ethiopia, Africa

https://australianmuseum.net.au/australopithecus-afarensis



Key fossil discoveries

During the 1970s, two fossil hunting teams began uncovering evidence of ancient humanancestors in east Africa. One team, co-led by Donald Johanson, was working at Hadar inEthiopia. The other team led by Mary Leakey, was over 1,500 kilometres away at Laetoli inTanzania. Fossils discovered at the two sites were found to have very similar features andages but they did not match the fossils of any species known at that time. A new speciesname, Australopithecus afarensis, was therefore created for them in 1978.

This species is now represented by several hundred fossils from east Africa.

Important specimens

‘Lucy’AL 288-1 – a partial skeleton discovered in 1974 by Donald Johanson inHadar, Ethiopia. This relatively complete female skeleton, dated to 3.2 million yearsold, is the most famous individual from this species. She was nicknamed ‘Lucy’ afterthe song ‘Lucy in the sky with diamonds’ sung by The Beatles. This song was verypopular at the time she was found. Lucy was only about 110 centimetres tall but wasa fully grown adult when she died. She was bipedal which means she could walk ontwo legs but she probably also spent a lot of time climbing trees in search of food orshelter. Knee AL 129 1a + 1b discovered in 1973 in Hadar, Ethiopia. When this 3.4 millionyear old knee was discovered, it was the rst fossil to provide evidence that ourancestors that had been walking on two legs for more than three million years. Thediscovery of this fossil encouraged Donald Johanson’s team to return to Hadar wherethey ultimately found ‘Lucy’ and hundreds of other fossils of this species. LH 4 – a lower jaw discovered in 1974 by Mary Leakey’s team in Laetoli, Tanzania.This fossil is the ‘type specimen’ or official representative of this species.




The ‘First Family’ - a group of Australopithecus afarensis fossils discovered in Hadar,Ethiopia in 1975. It became known as the ‘First Family’ because it contained fossilsfrom nine adults and four children. Some unknown disaster overcame this familygroup, burying them all at the same time. This important nd has allowed scientiststo gather insights into the biology and development of a single fossil species. It alsoprovided evidence that this species lived in small groups based on possible familybonds. ‘Selam’ or ‘Lucy’s baby – a partial juvenile skeleton discovered in 2000 in Dikika,Hadar, in Ethiopia. She lived 3.3 million years ago and was about 3 years old whenshe died. Bones are preserved that have never before been found in this species. This isthe earliest juvenile hominin skeleton ever found and should provide fantasticopportunities to uncover more about this species and about how our early ancestorsdeveloped. 'Lucy's big brother', nicknamed Kadanuumuu ('big man' in Afar) - a partial skeletonof a male uncovered in Afar, Ethiopia. An arm bone was rst found in 2005 andother parts recovered over the next four years included shoulder blade, ribs, neckvertebra, pelvis, leg bones (complete tibia and partial femur) and a collarbone. Thisindividual stood about 1.6 metres tall (30% larger than Lucy) and lived about 3.6million years ago.

Laetoli footprints

These fossil footprints were discovered in Tanzania, East Africa and date to 3.6 millionyears ago. Fossil bones from Australopithecus afarensis have been found nearby so it ispresumed that they left the tracks.

The quite human-like footprints were made by hominins that walked through a layer ofash burst that had settled on the ground after a distant volcano erupted. Raindrops madethe ash damp and, even now, the indentations made by these raindrops can still be seen onparts of the ash layer. At rst glance, it looks like two people walked side-by-side. The oneon the left was much smaller than the other and may have been a child. On closerexamination, we




can see that the prints on the right-hand side are blurred and were actually made by twoadults - one following the other and treading into the prints left by the rst. Part way alongthe trail the individuals pause and turn to the left before continuing. The sun soon driedthe damp ash, which hardened like cement. The active volcano continued to throw out ashuntil a layer up to 20 centimetres thick blanketed both the ground and the footprints.

Over millions of years, additional sediments were deposited and some were eroded away bywind and water. Eventually some of the footsteps lay uncovered. Then a lucky fossilhunter came across them and the story began to be revealed.

The footprints are of major signi cance as they are the rst direct evidence (ie not fossilsbones) that our ancestors were walking upright by 3.6 million years ago. The fossilfootprints are very similar to our own footprints. They show that the heel was the rst partof the foot to strike the ground. The big toe was aligned with the other toes and left a deepimpression showing that each step ended with the toe pushing downwards. The feet alsohad central arches to help launch the body into each step.

Distribution

Fossils have been found at Hadar in Ethiopia and Laetoli in Tanzania, about 1,500kilometres away.

Relationships with other speciesAustralopithecus afarensis is usually considered to be a direct ancestor of humans. It is alsoconsidered to be a direct ancestor of later species of Australopithecus and all species in theParanthropus genus.

The names Praeanthropus africanus and Praeanthropus afarensis have been suggested asalternatives by researchers who believe this species does not belong in the genusAustralopithecus.




Key physical featuresFossils show this species was bipedal (able to walk on two legs) but still retained many ape-like features including adaptations for tree climbing, a small brain, and a long jaw.

Body size and shape

females grew to only a little over one metre in height (105 – 110 centimetres) andmales were much larger at about 150 centimetres in height rib cage was cone-shaped like those of apes

Brain

brain was small, averaging approximately 430 cubic centimetres and comprised about1.3% of their body weight reorganisation of the brain may have begun with some enlargement to parts of thecerebral cortex

Skull

many cranial features were quite ape-like, including a low, sloping forehead, aprojecting face, and prominent brow ridges above the eyes. unlike most modern apes, this species did not have a deep groove lying behind itsbrow ridge and the spinal cord emerged from the central part of the skull base ratherthan from the back. males had a bony ridge (a sagittal crest) on top of their skull for the attachment ofenormous jaw muscles. In this species, the crest was very short and located toward therear of the skull.

a small hyoid bone (which helps anchor the tongue and voice box)found in a juvenilespecimen suggests A.afarensis had a chimp-like voice box semi-circular ear canal similar in shape to African apes and A.africanus, suggestingthis species was not as fast or agile on two legs as modern humans




Jaws and teeth

jaws and teeth were intermediate between those of humans and apes: jaws were relatively long and narrow. In the lower jaw, the teeth were arranged inrows that were slightly wider apart at the back than at the front. In the upper jaw, theplacement of the last molar results in tooth rows that curve in at the back. front incisor teeth were quite wide. canine teeth were pointed and were longer than the other teeth. Canine size wasintermediate between that of apes and humans. Like apes, males had much largercanines than females. a gap (diastema) was often present between the canines and adjacent teeth. This ape-like feature occurred between the canines and incisors in the upper jaw, and betweenthe canines and premolars of the lower jaw. premolar teeth in the lower jaw had ape-like cusps (bumps on the chewing surface).The front premolar tended to have one large cusp (ape-like) rather than two equal-sized cusps as in humans. back molar teeth were moderate in size and were human-like in having a ‘Y-5’pattern. That is, they had ve cusps arranged so that the grooves between the cuspsform a Y-shape.

Pelvis

pelvis was human-like as it was short and wide, but it lacked the re nements that enablehumans to walk with a striding gait

Limbs

limbs displayed human-like features that indicate an ability to walk on two legs femurs (thigh bones) that slanted in toward the knee knees with enlarged and strengthened outer condyles

arched feet and wide heels big toes aligned with the other toes and not opposable ape-like features that suggest an ability to climb trees




powerful arms with long forearms very short thigh bones long, curved finger and toe bones. shoulder blade socket that faces upwards like an ape’s, rather than to the side like ahuman’s, but shared other similarities with human shoulder blades

LifestyleCulture

This species probably used simple tools that may have included sticks and other non-durable plant materials found in the immediate surroundings. Stones may also have beenused as tools, but there is no evidence that stones were shaped or modi ed in any way. Itseems likely that they lived in small social groups containing a mixture of males andfemales, children and adults. Females were much smaller than males.

In 2010, fossil bones bearing cut marks were found in Dikika in Ethiopia, dating to about3.4 million years old. These bones show clear evidence of stone tools being used to remove

esh and to possibly smash bone in order to obtain marrow. No actual tools were found soit is not known whether the 'tools' were deliberately modi ed or just usefully-shapedstones. Although no hominin remains were found at the site, the discoverers believeAustralopithecus afarensis was responsible for the cut marks as no other hominin speciesdating to this period have been found in this region.

Environment and diet

This species occupied a range of environments. Some populations lived in savannah orsparse woodland, others lived in denser forests beside lakes. Analysis of their teeth, skulland body shape indicates a diet that consisted mainly of plants. However, fossil animalbones with cut marks found in Dikika in 2010 have been attributed to this species,suggesting they may have included signi cant amounts of meat in their diets. Microscopicanalysis of their




tooth enamel shows that they mostly ate fruits and leaves rather than seeds and other hardplant material. Their cone-shaped rib cage indicates they had large bellies adapted to arelatively low quality and high bulk diet. The position of the sagittal crest toward the backof the skull indicates that the front teeth processed most of the food.

Fran Dorey , Exhibition Project Coordinator Beth Blaxland , Education Project Officer Last Updated: 30 October 2015


https://australianmuseum.net.au/staff/fran-dorey

https://australianmuseum.net.au/staff/beth-blaxland


(03) Australopithecus afarensis essay | Becoming Human

Australopithecus afarensis

The rst specimens attributed toAustralopithecus afarensis were discovered in the1970’s by Donald Johanson working in the AfarTriangle of Ethiopia at the site of Hadar. Asuccession of spectacular discoveries, including aknee joint, the famous Lucy skeleton, and theremains of a family group, ensured that Au,afarensis would come to occupy a prominentplace on the hominin family tree. In addition tothe impressive nds located by Johanson and hisinternational team of scientists, further amazingdiscoveries were uncovered by Mary Leakey andher team, four years later and far to the south ofEthiopia, at the site of Laetoli, on the edge of theSerengeti Plains in Tanzania. Leakey’s team

discovered trace fossils of footprints of hundreds of animals, preserved in an ash layer thatwas securely dated to 3.6 ma. Amongst the animal footprints were some 70 footprints ofhominins, captured as they walked bipedally across a wet, muddy plain.

The remains from all sites attributed to Au. afarensis have been dated to between 3.9 and3.0 million years. This is a long time span, indicating that this taxon was a successfulspecies of hominin, persisting for almost a million years. Paleoanthropologists working inEthiopia and Tanzania over the last 40 years have recovered almost 400 specimens of Au.afarensis, including fossils from adult and juvenile males and females. These specimenshave been invaluable for telling us about the di erences between males and females, andfor giving insight into how Au. afarensis individuals changed as they aged. Some of thisinformation is coming from a spectacular recent discovery from Dikika in Ethiopia, acrossthe river from Hadar: the relatively complete skeleton of a three year old female.

http://www.becominghuman.org/node/australopithecus-afarensis-essay



The skull of Au. afarensis is characterized by a prognathic (projecting) face and a relativelysmall brain. Brain size estimates range from 380-550 cc, which is somewhat larger than theaverage contemporary chimpanzee. The jaw muscles were quite large, as evidenced by thelarge crests on the skull. There is strong sexual dimorphism in the skull nd post crania ofthis species; thus males were larger than females, and had larger canine teeth as well. Thedegree of difference between males and females is similar to what is seen in African apes.

There is a wealth of postcranial bones belonging to this species, including the partialskeleton of Lucy, o cially designated AL 288-1. Au. afarensis certainly was bipedal(walked fully upright on two legs), but there has been considerable debate amongresearchers on exactly how this species walked. The Laetoli footprints, the shape of thepelvis, the curvature of the vertebral column, and the anatomy of the knee all indicate Au.afarensis walked on two legs. However, there are many di erences in anatomy betweenthis taxon and modern humans, which have led some paleoanthropologists to argue thatAu. afarensis incorporated a degree of arboreal climbing into its locomotor repertoire. andits stride, or gait, was not like ours. These di erences include proportionally short legs andlonger arms, long, curved nger and toe bones, and subtle di erences in the bones of thehip.

The earliest stone tools were found at a site called Gona in Ethiopia in 1994. Radiometricdating gave an age of 2.6 million years but no human remains were found in the samecontext and it could not be known which of the several hominin species extant at the timewas the maker. Thirty and more years before, stone tools had been discovered at OlduvaiGorge where remains of several species of Australopithecus and Homo,dated to aroundtwo million years ago, were plentiful. Whether a late australopithecine or an early Homomade these tools could not be stated with certainty but researchers have generally assumedthe slightly larger brain size of early Homo placed the maker in that lineage rather than theslightly smaller brained Australopithecus.




These assumptions have been challenged by the discovery in 2009 of two small pieces ofbone airing striations made by stone. One bone was from an antelope sized animal and theother from a bovid the size of a modern cow. The bones were found at Dikika, Ethiopiawithin the securely dated Sidi Hakoma formation and given an age of 3.4 million years. By process of elimination, trampling of the bones underfoot by animals, toothmarks ortheir having been tumbled in a stream were ruled out and the only explanation for themarkings appears to be the use of stone to scrape esh from the bones and striking one ofthe bones to fracture it and extract the marrow.

Australopithecus afarensis is the only hominin taxon known to be present in this areabetween four and three million years ago and these bone markings would seem to settle theargument as to who was the first user of stone tools.

It is important to keep in mind the distinction between making and using stone tools. Nostones fashioned during this period for use as implements have been found at Dikika orHadar. The most likely explanation is whoever was de eshing these bones used a naturallyshaped stone lying nearby and it cannot be said with certainty that Australopithecusafarensis were fashioning stone for particular uses more than three million years ago.Shaping stone to produce a point or cutting edge seems to have been developed later.



(04) Lucy's Story | Institute of Human Origins

Lucy was found by Donald Johanson and Tom Grayon November 24, 1974, at the site of Hadar in Ethiopia.

When and where was Lucy found?Lucy was found by Donald Johanson (link is external)and Tom Gray on November 24, 1974, at the site ofHadar in Ethiopia. They had taken a Land Rover outthat day to map in another locality. After a long, hotmorning of mapping and surveying for fossils, theydecided to head back to the vehicle. Johanson suggestedtaking an alternate route back to the Land Rover,through a nearby gully. Within moments, he spotted aright proximal ulna (forearm bone) and quicklyidenti ed it as a hominid. Shortly thereafter, he saw anoccipital (skull) bone, then a femur, some ribs, a pelvis,and the lower jaw.

Two weeks later, after many hours of excavation,screening, and sorting, several hundred fragments ofbone had been recovered, representing 40 percent of asingle hominid skeleton.

https://iho.asu.edu/about/lucys-story

https://isearch.asu.edu/profile/50790



How did Lucy get her name?Later in the night of November 24, there was much celebration and excitement over thediscovery of what looked like a fairly complete hominid skeleton. There was drinking,dancing, and singing; the Beatles’ song “Lucy in the Sky With Diamonds” was playing overand over. At some point during that night, no one remembers when or by whom, theskeleton was given the name “Lucy.” The name has stuck.

How do we know she was a hominid?The term hominid refers to a member of the zoological family Hominidae. Hominidaeencompasses all species originating after the human/African ape ancestral split, leading toand including all species of Australopithecus and Homo. While these species di er inmany ways, hominids share a suite of characteristics that de ne them as a group. The mostconspicuous of these traits is bipedal locomotion, or walking upright.

How do we know Lucy walked upright?As in a modern human’s skeleton, Lucy's bones are rife with evidence clearly pointing tobipedality. Her distal femur shows several traits unique to bipedality. The shaft is angledrelative to the condyles (knee joint surfaces), which allows bipeds to balance on one leg at atime during locomotion. There is a prominent patellar lip to keep the patella (knee cap)from dislocating due to this angle. Her condyles are large and are thus adapted to handlingthe added weight that results from shifting from four limbs to two. The pelvis exhibits anumber of adaptations to bipedality. The entire structure has been remodeled toaccommodate an upright stance and the need to balance the trunk on only one limb witheach stride. The talus, in her ankle, shows evidence for a convergent big toe, sacri cingmanipulative abilities for efficiency in bipedal locomotion. The vertebrae show evidence ofthe spinal curvatures necessitated by a permanent upright stance.




How do we know she was female?Evidence now strongly suggests that the Hadar material, as well as fossils from elsewhere inEast Africa from the same time period, belong to a single, sexually dimorphic speciesknown as Australopithecus afarensis. At Hadar, the size di erence is very clear, with largermales and smaller females being fairly easy to distinguish. Lucy clearly ts into the smallergroup.

How did she die?No cause has been determined for Lucy’s death. One of the few clues we have is theconspicuous lack of postmortem carnivore and scavenger marks. Typically, animals thatwere killed by predators and then scavenged by other animals (such as hyaenas) will showevidence of chewing, crushing, and gnawing on the bones. The ends of long bones areoften missing, and their shafts are sometimes broken (which enables the predator to get tothe marrow). In contrast, the only damage we see on Lucy's bones is a single carnivoretooth puncture mark on the top of her left pubic bone. This is what is called a perimorteminjury, one occurring at or around the time of death. If it occurred after she died but whilethe bone was still fresh, then it may not be related to her death.

How old was she when she died?There are several indicators which give a fair idea of her age. Her third molars (“wisdomteeth”) are erupted and slightly worn, indicating that she was fully adult. All the ends ofher bones had fused and her cranial sutures had closed, indicating completed skeletaldevelopment. Her vertebrae show signs of degenerative disease, but this is not alwaysassociated with older age. All these indicators, when taken together, suggest that she was ayoung, but fully mature, adult when she died.




Where is the "real" Lucy?IHO has replicas of Lucy‘s bones, which were produced in the Institute‘s casting andmolding laboratories. The “real” Lucy is stored in a specially constructed safe in thePaleoanthropology Laboratories of the National Museum of Ethiopia in Addis Ababa,Ethiopia. Because of the rare and fragile nature of many fossils, including hominids, moldsare often made of the original fossils. The molds are then used to create detailed copies,called casts, which can be used for teaching, research, and exhibits.

How old is Lucy?The hominid-bearing sediments in the Hadar formation are divided into three members.Lucy was found in the highest of these—the Kada Hadar or KH—member. While fossilscannot be dated directly, the deposits in which they are found sometimes contain volcanic

ows and ashes, which can now be dated with the 40Ar/39Ar (Argon-Argon) datingtechnique. Armed with these dates and bolstered by paleomagnetic, paleontological, andsedimentological studies, researchers can place fossils into a dated framework with accuracyand precision. Lucy is dated to just less than 3.18 million years old.

How do we know that her skeleton is from a single individual?Although several hundred fragments of hominid bone were found at the Lucy site, therewas no duplication of bones. A single duplication of even the most modest of bonefragments would have disproved the single skeleton claim, but no such duplication is seenin Lucy. The bones all come from an individual of a single species, a single size, and asingle developmental age. In life, she would have stood about three-and-a-half feet tall, andweighed about 60 to 65 pounds.

"Lucy" illustration by Michael Hagelberg.

http://www.rrstar.com/article/20140724/Blogs/140729599


(05) "Lucy" has some 'splaining to do on 10 percent brain myth

Hollywood’s latest super-powered heroineperpetuates a widely believed myth about thecapacity of the human brain.

“The average person uses 10 percent of theirbrain capacity. Imagine what she could do with100 percent,” the tagline for “Lucy,” played byScarlett Johansson, reads.

This concept is apparently meant to deliverAmerican audiences exactly what they’reclamoring for: a movie that showcases ScarlettJohansson’s brains.

The problem with the movie premise, of course,is that we all use 100 percent of our brain, eventhe Kardashians.

But it’s still widely believed that people can only access 10 percent of their brain. Two-thirds of the public believe the 10 percent myth to be true, Psychology Today reported inits debunking of "Lucy." Worse yet, about 48 percent of teachers surveyed in 2012 byFrontiers in Psychology believed the myth to be true.

“Lucy,” like “Limitless” which came before it, relies on the myth to explain its titularcharacters superpowers. These are works of ction, so perhaps the bad science shouldn’tbother us any more than when a movie proclaims a radioactive spider can suddenly makeyou stick to walls or be able to pull-off an all-spandex jumpsuit.

But since, unlike Spiderman, a wide range of people tend to believe the 10 percent myth, itseems appropriate to use the release of “Lucy” as another opportunity to debunk myth andincrease our scientific literacy.


http://www.csicop.org/si/show/the_ten-percent_myth/



Cue Dr. Deepak Nair, a neurologist with the Illinois Neurological Institute, a part of OSFHealthCare.

Dr. Nair explains that the brain is packed with billions of neurons that are always at workwith one task or another. And despite the popular myth, we all use 100 percent of ourbrain.

“There are no unknown parts of the brain,” Nair said. “We have attributed a function anda purpose to every part of the neural anatomy.”

We know that more than 10 percent of the brain is used because doctors have multipleways of watching the brain in action, such as electroencephalography (EEG) and positronemission tomography (PET), Nair said. The technology has proven that the brain’sneurons are working at a variety of levels, 24-7.

Nair said that although the brain accounts for about 2-3 percent of your bodyweight, it isresponsible for using up to and perhaps more than 20 percent of your energy supply at anygiven moment.

“It is the most metabolically active part of your body. It never turns o ,” Nair said. “Evenwhen you’re not aware of it, your brain is always doing something because it has to controleverything.”

One thing that might perpetuate the 10 percent myth is that neurons, the brain cells thattransmit information to other nerve cells, are outnumbered by glial cells. Glial cells are thesupport structure and insulation of the brain, Nair said. Most glial cells primarily serve asthe physical support for neurons.

If the science doesn’t interest you, Nair o ers a more common sense reasoning for why the10 percent myth is false: “Do we honestly think that if we removed 90 percent of yourbrain that you would be unchanged?”


http://www.osfsaintfrancis.org/physicians/profile/2424/deepak-s-nair-md/

http://blogs.scientificamerican.com/brainwaves/2012/06/13/know-your-neurons-what-is-the-ratio-of-glia-to-neurons-in-the-brain/



“Every part of the brain is important; even small amounts of injury can be devastating,” hesaid.

Still, Nair said the faulty premise shouldn’t keep people away from having a good time atthe movies: So long as they don’t let the premise get to their head.

“From an entertainment standpoint, I certainly see no harm in it,” he said. “So long asthese don’t become self-evident truths that everyone falls for and keeps us fromunderstanding the reality of what we know about the body.”



(06) Do People Only Use 10 Percent of Their Brains?

Credit: OlegPrikhodko/iStockPhoto

The human brain iscomplex. Along withperforming millions ofmundane acts, it composesconcertos, issues manifestosand comes up with elegantsolutions to equations. It'sthe wellspring of all humanfeelings, behaviors,experiences as well as therepository of memory andself-awareness. So it's nosurprise that the brainremains a mystery unto

itself.

Adding to that mystery is the contention that humans "only" employ 10 percent of theirbrain. If only regular folk could tap that other 90 percent, they too could become savantswho remember to the twenty-thousandth decimal place or perhaps even have telekineticpowers.

Though an alluring idea, the "10 percent myth" is so wrong it is almost laughable, saysneurologist Barry Gordon at Johns Hopkins School of Medicine in Baltimore. Althoughthere's no de nitive culprit to pin the blame on for starting this legend, the notion hasbeen linked to the American psychologist and author William James, who argued in TheEnergies of Men that "We are making use of only a small part of our possible mental andphysical resources." It's also been associated with Albert Einstein, who supposedly used it toexplain his cosmic towering intellect.

https://www.scientificamerican.com/article/do-people-only-use-10-percent-of-their-brains/



The myth's durability, Gordon says, stems from people's conceptions about their ownbrains: they see their own shortcomings as evidence of the existence of untapped graymatter. This is a false assumption. What is correct, however, is that at certain moments inanyone's life, such as when we are simply at rest and thinking, we may be using only 10percent of our brains.

"It turns out though, that we use virtually every part of the brain, and that [most of] thebrain is active almost all the time," Gordon adds. "Let's put it this way: the brain representsthree percent of the body's weight and uses 20 percent of the body's energy."

The average human brain weighs about three pounds and comprises the hefty cerebrum,which is the largest portion and performs all higher cognitive functions; the cerebellum,responsible for motor functions, such as the coordination of movement and balance; andthe brain stem, dedicated to involuntary functions like breathing. The majority of theenergy consumed by the brain powers the rapid ring of millions of neuronscommunicating with each other. Scientists think it is such neuronal ring and connectingthat gives rise to all of the brain's higher functions. The rest of its energy is used forcontrolling other activities—both unconscious activities, such as heart rate, and consciousones, such as driving a car.

Although it's true that at any given moment all of the brain's regions are not concurrentlyring, brain researchers using imaging technology have shown that, like the body's

muscles, most are continually active over a 24-hour period. "Evidence would show over aday you use 100 percent of the brain," says John Henley, a neurologist at the Mayo Clinicin Rochester, Minn. Even in sleep, areas such as the frontal cortex, which controls thingslike higher level thinking and self-awareness, or the somatosensory areas, which help peoplesense their surroundings, are active, Henley explains.

Take the simple act of pouring co ee in the morning: In walking toward the co eepot,reaching for it, pouring the brew into the mug, even leaving extra room for cream, theoccipital and parietal lobes, motor sensory and sensory motor cortices, basal ganglia,cerebellum and frontal lobes all activate. A lightning storm of neuronal activity occursalmost across the entire brain in the time span of a few seconds.




"This isn't to say that if the brain were damaged that you wouldn't be able to perform dailyduties," Henley continues. "There are people who have injured their brains or had parts ofit removed who still live fairly normal lives, but that is because the brain has a way ofcompensating and making sure that what's left takes over the activity."

Being able to map the brain's various regions and functions is part and parcel ofunderstanding the possible side e ects should a given region begin to fail. Experts knowthat neurons that perform similar functions tend to cluster together. For example, neuronsthat control the thumb's movement are arranged next to those that control the fore nger.Thus, when undertaking brain surgery, neurosurgeons carefully avoid neural clustersrelated to vision, hearing and movement, enabling the brain to retain as many of itsfunctions as possible.

What's not understood is how clusters of neurons from the diverse regions of the braincollaborate to form consciousness. So far, there's no evidence that there is one site forconsciousness, which leads experts to believe that it is truly a collective neural e ort.Another mystery hidden within our crinkled cortices is that out of all the brain's cells, only10 percent are neurons; the other 90 percent are glial cells, which encapsulate and supportneurons, but whose function remains largely unknown. Ultimately, it's not that we use 10percent of our brains, merely that we only understand about 10 percent of how itfunctions.

Robynne Boyd



(07) Ludwig in the Sky With Diamonds

Was our famous australopithecine ancestorWas our famous australopithecine ancestorLucy really a man? Lucy really a man?

After anthropologists excavated her 3-million-year-old skeleton in Ethiopia in 1974--and namedher for a Beatles song playing at the site on thediscovery day--they soon became convinced itwas female.

Why? Why?

Lucy is small compared with other specimens ofAustralopithecus afarensis found at the same site.But a pair of paleoanthropologists from theUniversity of Zurich have now called Lucy’s

femininity into question. Martin Häusler and Peter Schmid compared casts of Lucy’sreconstructed pelvis with a modern woman’s pelvis (bottom) and the cast of anotheraustralopithecine specimen from South Africa. At least 13 of Lucy’s features--most notably the promontorium, a ridge at the rear of thepelvis that makes it heart shaped--say male. The researchers also found that anaustralopithecine baby’s head probably could not have t through Lucy’s pelvic opening,as shown here. (The skulls in the two nonhuman pelvises are human baby skulls scaleddown to the likely size of an australopithecine baby’s head, of which no fossils exist.) SoLucy may have been male--or a member of an entirely di erent species. Should her namebe changed? Häusler and Schmid suggest Lucifer as an alternative. Or maybe Ludwig, saysSchmid. But that’s too German.

http://discovermagazine.com/1996/mar/ludwigintheskywi726

http://discovermagazine.com/1996/mar/ludwigintheskywi726

(08) Baboon bone found in famous Lucy skeleton

(Image: Dave Einsel/Getty)

One of these vertebrae does not belong to Lucy

Lucy, arguably the world’s most famous early human fossil, is not quite all she seems. Acareful look at the ancient hominin’s skeleton suggests one bone may actually belong to ababoon.

In November 1974, palaeoanthropologists Donald Johanson and Tom Gray made thediscovery of a lifetime near the village of Hadar in Ethiopia: dozens of fossil fragmentsbelonging to a single hominin skeleton dating back 3.2 million years.

Once the fragments had been pieced together, the skeleton was declared to be of the speciesAustralopithecus afarensis. But the skeleton became known as Lucy, inspired by a Beatlessong that blasted out of a cassette player as the researchers celebrated their discovery thatevening.

https://www.newscientist.com/article/dn27325-baboon-bone-found-in-famous-lucy-skeleton/

https://www.newscientist.com/article/mg19125703-300-the-amazing-fossil-of-lucys-little-sister

http://humanorigins.si.edu/evidence/human-fossils/fossils/al-288-1


(08) Baboon bone found in famous Lucy skeleton

Forty years later, thanks to its age and completeness, Lucy remains an important specimen.It shows, for instance, that our distant ancestors began to walk upright on two legs longbefore they developed big brains.

It’s no surprise, then, that replicas of the skeleton are on display at museums across theworld. But when Gary Sawyer and Mike Smith at the American Museum of NaturalHistory in New York recently began work on a new reconstruction of Lucy’s skeleton,with help from Scott Williams at New York University, they noticed something odd.

“Mike pointed out that one of the [vertebra] fragments, which no one, including me, hadreally paid close attention to, looked fairly small to t with the rest of Lucy’s vertebralcolumn,” says Williams.

Williams had been working with Marc Meyer at Cha ey College in Rancho Cucamonga,California, on the spinal column of another early hominin, Australopithecus sediba, andso the two researchers decided to study the fragment.

They soon concluded that it didn’t belong to Lucy. “It was just too small,” says Williams.

One possible explanation was that the vertebra fragment came from a second, juvenilemember of Lucy’s species. So Williams and Meyer did a comparative study that includedvertebrae from other Australopithecus fossils. To satisfy a personal hunch, Williams alsoadded vertebrae from other animals known to have lived in the Hadar region 3.2 millionyears ago, such as porcupines and pigs. The results showed, surprisingly, that the fragmentmay not have belonged to Australopithecus at all.

“Baboons were a close match, both in shape and size,” says Williams. “So we think we’vesolved this mystery. It seems that a fossil gelada baboon thoracic vertebra washed or wasotherwise transported in the mix of Lucy’s remains.”


https://www.newscientist.com/blogs/shortsharpscience/2011/02/the-twist-that-shows-lucy-wasn.html


(08)Baboon bone found in famous Lucy skeleton

He stresses, though, that the analysis, which he will present at a meeting of thePaleoanthropology Society in San Francisco next week, also con rms that the other 88fossil fragments belonging to Lucy’s skeleton are correctly identi ed. And the mislabelledbaboon bone fragment doesn’t undermine Lucy’s important position in the evolution ofour lineage.

“There was no reason to assume intermingling of elements between two different animals”

There may be a simple reason why no one noticed that Lucy’s remains included a baboonbone fragment.

Although many scientists have examined Lucy’s skeleton, most experts have not worked asextensively on bones of the back relative to the limbs, says Dan Gebo at the NorthernIllinois University in DeKalb. “Given that broken bones are always a problem and most ofus are not vertebral specialists, it would not be unusual to make a small mistake.”

Also, there was no sign of a baboon skeleton at the site where Lucy was discovered in 1974,says William Sanders at the University of Michigan in Ann Arbor. “So there was no reasonto assume intermingling of elements between two different animals,” he says.

Even so, Sanders wants to see the analysis in detail before he accepts that the vertebrafragment really does belong to a baboon. “O hand, I don’t see any morphological featuresin this element that cry out for recognition as a baboon,” he says.

If the fragment really does prove to belong to a baboon, he says, “we can cut DonJohanson and his colleagues some slack”.


http://www.paleoanthro.org/meetings/2015/


(01) australopithecus afarensis | the smithsonianaustralopithecus means ‘southern ape’ and was...

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