ANTHRO101 Maricopa Community Colleges Neanderthals Presentation Sources:
https://www.youtube.com/watch?v=NEz2TfqTCkk for StudyGuide A
https://www.youtube.com/watch?v=FAw0zrnCTbs for Studyguide B
https://video.nationalgeographic.com/video/ng-live/00000155-9294-df34-ab75-d29764c90000 only watch part 1
https://news.nationalgeographic.com/2017/05/homo-naledi-human-evolution-science/ read after the video above
https://news.nationalgeographic.com/2018/02/neanderthals-cave-art-humans-evolution-science/
Activity :
Create a lesson plan or short powerpoint presentation targeted to 7th and 8th graders about Neanderthals. It must have visuals, and descriptions of their bodies (from fossil skeletons), their life ways, artifacts, capacities, and theories about what likely happened to them. Your “lesson” must have the most up to date information, and be written at a level appropriate for middle-schoolers. You must use information from the articles above, and you may do additional research and obtain visual images of Neanderthals from websites. You must cite your sources at the end or on a separate page.
StudyGuide:
Answer Questions in the attached doc files of studyguide A and B First of Our Kind
Author(s): Kate Wong
Source: Scientific American, Vol. 306, No. 4 (April 2012), pp. 30-39
Published by: Scientific American, a division of Nature America, Inc.
Stable URL: https://www.jstor.org/stable/26014323
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30 Scientific American, April 2012
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Photograph by Tktk Tktk
H U M A N EVO LU T I O N
First of
Our Kind
Sensational fossils from South Africa spark debate
over how we came to be human
By Kate Wong
BRENT STIRTON Getty Images
IN BRIEF
The origin of our genus, Homo, is one of the
biggest mysteries facing scholars of human
evolution.
Based on the meager evidence available, sci
entists have surmised that Homo arose in East
Africa, with Lucy’s species, Australopithecus
afarensis, giving rise to the founding member
of our lineage, Homo habilis.
Recently discovered fossils from a site north
west of Johannesburg, South Africa, could up
end that scenario. The fossils represent a pre
viously unknown species of human with an
amalgam of australopithecine and Homo traits
that suggest to its discoverers that it could be
the ancestor of Homo.
NEW HUMAN SPECIES from South Africa—Australopithecus sediba—
has been held up as the ancestor of our genus, Homo.
April 2012, ScientificAmerican.com 31
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S
ometime between three million and two
million years ago, perhaps on a primeval
savanna in Africa, our ancestors became
recognizably human. For more than a million years their australopithecine predecessors—Lucy and her kind, who walked
upright like us yet still possessed the stubby legs, tree-climbing hands and small brains of their ape fore
bears—had thrived in and around the continent’s forests and
woodlands. But their world was changing. Shifting climate favored the spread of open grasslands, and the early australopithecines gave rise to new lineages. One of these offshoots evolved
long legs, toolmaking hands and an enormous brain. This was
our genus, Homo, the primate that would rule the planet.
For decades paleoanthropologists have combed remote corners of Africa on hand and knee for fossils of Homo’s earliest
representatives, seeking to understand the details of how our
genus rose to prominence. Their efforts have brought only modest gains—a jawbone here, a handful of teeth there. Most of the
recovered fossils instead belong to either ancestral australopithecines or later members of Homo—creatures too advanced to illuminate the order in which our distinctive traits arose or the
selective pressures that fostered their emergence. Specimens
older than two million years with multiple skeletal elements
preserved that could reveal how the Homo body plan came together eluded discovery. Scientists’ best guess is that the transition occurred in East Africa, where the oldest fossils attributed
to Homo have turned up, and that Homo’s hallmark characteristics allowed it to incorporate more meat into its diet—a rich
source of calories in an environment where fruits and nuts had
become scarce. But with so little evidence to go on, the origin of
our genus has remained as mysterious as ever.
Lee Berger thinks he has found a big piece of the puzzle. A
paleoanthropologist at the University of the Witwatersrand in
Johannesburg, South Africa, he recently discovered a trove of
fossils that he and his team believe could revolutionize researchers’ understanding of Homo’s roots. In the white-walled confines
of room 210 at the university’s Institute for Human Evolution, he
watches as Bernard Wood of George Washington University paces in front of the four plastic cases that have been removed from
their fireproof safe and placed on a table clothed in royal blue
velvet. The foam-lined cases are open, revealing the nearly twomillion-year-old fossils inside. One holds pelvis and leg bones.
Another contains ribs and vertebrae. A third displays arm
bones and a clavicle. And a fourth houses a skull. On a counter
opposite the table, more cases hold a second partial skeleton,
including a nearly complete hand.
Wood, a highly influential figure
in the field, pauses in front of the
skull and leans in for a closer look. He
strokes his beard as he considers the
dainty teeth, the grapefruit-size braincase. Straightening back up, he shakes
his head. “I’m not often at a loss for
words,” he says slowly, almost as if to himself, “but wow. Just wow.”
Berger grins. He has seen this reaction before. Since he unveiled the finds in 2010, scientists from all over the world have
been flocking to his lab to gawk at the breathtaking fossils.
Based on the unique anatomical package the skeletons present,
Berger and his team assigned the remains to a new species, Australopithecus sediba. They furthermore propose that the combination of primitive Australopithecus traits and advanced Homo
traits evident in the bones qualifies the species for a privileged
place on the family tree: as the ancestor of Homo. The stakes are
high. If Berger is right, paleoanthropologists will have to completely rethink where, when and how Homo got its start—and
what it means to be human in the first place.
THE ROAD NOT TAKEN
in the middle of the rock-strewn dirt road that winds through
the John Nash Nature Reserve, Berger brings the Jeep to a halt
and points to a smaller road that branches right. For 17 years he
had made the 40-kilometer trip northwest from Johannesburg
to the 9,000-hectare parcel of privately owned wilderness and
driven past this turnoff, continuing along the main road, past
the resident giraffes and warthogs and wildebeests, to a cave he
was excavating just a few kilometers away called Gladysvale. In
1948 American paleontologists Frank Peabody and Charles
Camp came to this area to look for fossils of hominins (modern
humans and their extinct relatives) on the advice of famed
South African paleontologist Robert Broom, who had found
such fossils in the caves of Sterkfontein and Swartkrans, eight
kilometers away. Peabody suspected that Broom had intentionally sent them on a wild goose chase, so unimpressed was he
with the sites here. Little did Berger or the expeditioners before
him know that had they only followed this smaller path—one of
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1
BRENT STIRTON Getty Images
2
LEE BERGER (left) and Meshack Kgasi (right) inspect the
miners’ pit at the Malapa site, where Berger discovered
Australopithecus sediba (1). Blocks of concretelike calcified clastic
sediment dislodged by miners will be CT-scanned to see if they
contain fossils (2). View captures the valleys in and around the
Malapa area, northwest of Johannesburg in South Africa (3).
3
April 2012, ScientificAmerican.com 33
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several miners’ tracks used in the early 1900s to cart the limestone that built Johannesburg from quarries out to the main
road—they would have made the discovery of a lifetime.
Berger, now 46 years old, never imagined he would find
something like A. sediba. Although he thought Homo might have
had roots in South Africa instead of East Africa, he knew the
odds of making a big find were slim. Hominin fossils are extremely rare, so “you don’t have any expectations,” he reflects.
What is more, he was focused on the so-called Cradle of Humankind, an already intensively explored region whose caves had
long been yielding australopithecines generally considered to
be more distantly related to Homo than the East African australopithecines seemed to be. And so Berger continued to toil at
Gladysvale day after day, year after year. Because he found little
in the way of hominins among the millions of animal fossils
there—just scraps of a species called A. africanus—he busied
himself with another goal: dating the site. A critical problem
with interpreting the South African hominin fossils was that scientists had not yet figured out how to reliably determine how old
they were. In East Africa, hominin fossils come from sediments
sandwiched between layers of volcanic ash that blanketed the
landscape during long-ago eruptions. Geologists can ascertain
how old an ash layer is by analyzing its chemical “fingerprint.” A
fossil that originates from a layer of sediment that sits in between two volcanic ashes is thus intermediate in age between
those two ashes. The cave sites in the Cradle of Humankind lack
volcanic ashes. Through his 17 years of trial and error at Gladysvale, however, Berger and his colleagues hit on techniques that
circumvented the problem of not having ash to work with.
Those techniques would soon come in very handy. On August 1, 2008, while surveying the reserve for potential new fossil
sites in the area that he had identified using Google Earth, Berger turned right on the miners’ track he had passed by for 17
years and followed it to a three- by four-meter hole in the
ground blasted by the miners. Eyeballing the site, he found a
handful of animal fossils—enough to warrant a trip back for a
closer look. He returned on August 15 with his then nine-yearold son, Matthew, and dog, Tau. Matthew took off into the bush
after Tau, and within minutes he shouted to his father that he
had found a fossil. Berger doubted it was anything important—
probably just an antelope bone—but in a show of fatherly support, he made his way over to inspect the find. There, protruding from a dark hunk of rock nestled in the tall grass by the
corpse of a lightning-struck tree, was the tip of a collarbone.
As soon as Berger laid eyes on it, he knew it belonged to a
hominin. In the months that followed he found more of the clavicle’s owner, along with another partial skeleton, 20 meters
away in the miners’ pit. To date, Berger and his team have recovered more than 220 bones of A. sediba from the site—more than
all the known early Homo bones combined. He christened the
site Malapa, meaning “homestead” in the local Sesotho language. Using the approaches honed at Gladysvale, the geologists
on Berger’s team would later date the remains with remarkable
precision to 1.977 million years ago, give or take 2,000 years.
A PATCHWORK PREDECESSOR
that the malapa fossils include so many body parts is important
because it means they can offer unique insights into the order in
which key Homo traits appeared. And what they show very
clearly is that quintessentially human features did not necessarily evolve as a package deal, as was thought. Take the pelvis and
the brain, for example. Conventional wisdom holds that the
broad, flat pelvis of australopithecines evolved into the bowlshaped pelvis seen in the bigger-brained Homo to allow delivery
of babies with larger heads. Yet A. sediba has a Homo-like pelvis
with a broad birth canal in conjunction with a teeny brain—just
420 cubic centimeters, a third of the size of our own brain. This
combination shows brain expansion was not driving the metamorphosis of the pelvis in A. sediba’s lineage.
Not only do the A. sediba fossils mingle old and new versions
of general features, such as brain size and pelvis shape, but the
pattern repeats at deeper levels, like an evolutionary fractal.
Analysis of the interior of the young male’s braincase shows that
the brain, while small, possessed an expanded frontal region, indicating an advanced reorganization of gray matter; the adult female’s upper limb pairs a long arm—a primitive holdover from a
tree-dwelling ancestor—with short, straight fingers adapted to
making and using tools (although the muscle markings on the
bones attest to powerful, apelike grasping capabilities). In some
instances, the juxtaposition of old and new is so improbable that
had the bones not been found joined together, researchers would
have interpreted them as belonging to entirely different creatures. The foot, for instance, combines a heel bone like an ancient
ape’s with an anklebone like Homo’s, according to Malapa team
member Bernard Zipfel of the University of the Witwatersrand. It
is as if evolution was playing Mr. Potato Head, as Berger puts it.
The extreme mosaicism evident in A. sediba, Berger says,
should be a lesson to paleoanthropologists. Had he found any
number of its bones in isolation, he would have classified them
differently. Based on the pelvis, he could have called it H. erectus. The arm alone suggests an ape. The anklebone is a match
for a modern human’s. And like the blind men studying the individual parts of the elephant, he would have been wrong. “Sediba
shows that one can no longer assign isolated bones to a genus,”
Berger asserts. That means, in his view, finds such as a 2.3-million-year-old upper jaw from Hadar, Ethiopia, that has been
held up as the earliest trace of Homo cannot safely be assumed
to have belonged to the Homo line.
Taking that jaw out of the running would make A. sediba older than any of the well-dated Homo fossils but still younger than
A. afarensis, putting it in pole position for the immediate ancestor of the genus, Berger’s team contends. Furthermore, considering A. sediba’s advanced features, the researchers propose that it
could be specifically ancestral to H. erectus (a portion of which is
considered by some to be a different species called H. ergaster).
Thus, instead of the traditional view in which A. afarensis begat
H. habilis, which begat H. erectus, he submits that A. africanus is
the likely ancestor of A. sediba, which then spawned H. erectus.
If so, that arrangement would relegate H. habilis to a deadend side branch of the human family tree. It might even kick
A. afarensis—long considered the ancestor of all later hominins,
including A. africanus and Homo—to the evolutionary curb, too.
Berger points out that A. sediba’s heel is more primitive than
that of A. afarensis, indicating that A. sediba either underwent
an evolutionary reversal toward a more primitive heel or that
it descended from a different lineage than the one that includes
A. afarensis and A. africanus—one that has yet to be discovered.
“In the South, we have a saying: ‘You dance with the girl you
34 Scientific American, April 2012
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FINDINGS
Mix and
Match
Adult female A. sediba
Young male A. sediba
Small
body
Australopithecus sediba skeletons exhibit a totally unexpected mix of australopithecine and Homo traits, representative examples of which
are shown here. Previously
scientists thought that Homo
features such as short arms
and dexterous hands evolved
in lockstep, but A. sediba
shows that they emerged
piecemeal—in this case marrying long, tree-climbing
arms with hands whose short
fingers and long thumb
would have enabled a humanlike precision grip. A. sediba’s particular blend suggests to Berger’s team that it
descended from A. africanus
or an unknown lineage
and gave rise directly to
H. erectus.
Expanded frontal
region of brain
Small
teeth
Small
brain
Projecting
nose
Big birth
canal
Long
arms
Dexterous
hand
Similar to
Australopithecus
Similar to
Homo
Advanced
anklebone
Long
legs
Primitive
heel bone
A. africanus
A. sediba
BRENT STIRTON Getty Images
H. erectus
April 2012, ScientificAmerican.com 35
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I N T E R P R E TAT I O N
Ancestor of Us All?
In the conventional view of the origin of Homo, Australopithecus afarensis gave rise to Homo habilis, which gave
rise to H. erectus and all later Homo species. But key aspects of A. sediba’s anatomy—including its heel, which is
more primitive than that of A. afarensis, and its hand, which
is more humanlike than that of H. habilis—raise the controversial possibility that A. sediba might be ancestral to
H. erectus and that A. afarensis and H. habilis might be
side branches.
Ardipithecus
Australopithecus
Kenyanthropus
Homo
A. aethiopicus
Fairly certain
Tentative
A. africanus
Undiscovered lineage ?
Early Homo
A. anamensis
A. afarensis
A. garhi
K. platyops
A. ramidus
4 million years ago
brought,’ ” quips Berger, who grew up on a farm in Sylvania, Ga.
“And that is what paleoanthropologists have been doing” in trying to piece together the origin of Homo from the fossils that
have turned up in East Africa. “Now we have to recognize there
is more potential out there,” he states. Maybe the East Side story
of human origins is wrong. The traditional view of South Africa’s oldest hominin fossils is that they represent a separate evolutionary experiment that ultimately fizzled out. A. sediba could
turn the tables and reveal, in South Africa, another lineage, the
one that ultimately gave rise to humankind as we know it (indeed, sediba is the Sesotho word for “fountain” or “wellspring”).
William Kimbel of Arizona State University, who led the team
that found the 2.3-million-year-old jawbone in Ethiopia, is having none of it. The idea that one needs a skeleton to classify a
specimen is a “nonsensical argument,” he retorts. The key is to
find pieces of anatomy that contain diagnostic traits, he says, and
the Hadar jaw has features clearly linking it to Homo, such as the
parabolic shape formed by its tooth rows. Kimbel, who has seen
the Malapa fossils but not studied them in depth, finds their Homo-like traits intriguing, although he is not sure what to make of
them. He scoffs at the suggestion that they are directly ancestral
to H. erectus, however. “I don’t see how a taxon with a few characteristics that look like Homo in South Africa can be the ancestor
[of Homo] when there’s something in East Africa that is clearly
Homo 300,000 years earlier,” he declares, referring to the jaw.
Kimbel is not alone in rejecting the argument for A. sediba as
the rootstock of Homo. “There are too many things that do not
fit, particularly the dates and geography,” comments Meave
Leakey of the Turkana Basin Institute in Kenya, whose own research has focused on fossils from East Africa. “It is much more
likely that the South African hominins are a separate radiation
that took place in the south of the continent.”
René Bobe of George Washington University says that if the
A. sediba remains were older—say, around 2.5 million years old—
3 mya
they might make for a plausible Homo ancestor. But at 1.977 million years old, they are just too primitive in their overall form to
be ancestral to fossils from Kenya’s Lake Turkana region that
are just a tad younger yet have many more indisputable Homo
traits. Berger co…
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