Nenek moyang manusia dengan otak yang kecil ditemukan--t-REC-komunitas reptil-semarang--KSE-komunitas satwa eksotik

10.06

Nenek moyang manusia dengan otak yang kecil ditemukan

SILAHKAN MENGGUNAKAN " MESIN TRANSLATE "..GOOGLE TRANSLATE
DISAMPING KANAN INI.............

PLEASE USE ........ "TRANSLATE MACHINE" .. GOOGLE TRANSLATE BESIDE RIGHT THIS

.................


T-REC -TUGUMUDA REPTILES COMMUNITY-INDONESIA


More info :
www.trecsemarang2011.blogspot.com
minat gabung : ( menerima keanggotaan seluruh kota dan daerah di Indonesia )
08995557626
..................................
KSE – KOMUNITAS SATWA EKSOTIK – EXOTIC PETS COMMUNITY-- INDONESIA
Visit Our Community and Joint W/ Us....Welcome All Over The World
www.facebook.com/groups/komunitassatwaeksotik/
 KSE = KOMUNITAS SATWA EKSOTIK

MENGATASI KENDALA MINAT DAN JARAK

KAMI ADA DI TIAP KOTA DI INDONESIA
DETAIL TENTANG KSE-----KLIK : www.komunitassatwaeksotik-pendaftaran.blogspot.com

GABUNG......... ( menerima keanggotaan seluruh kota dan daerah di Indonesia )
HUBUNGI   :  089617123865-08995557626

.........................

Nenek moyang manusia dengan otak yang kecil ditemukan

Homo Naledi menimbulkan pertanyaan menarik tentang masa lalu evolusi kita

Date:

September 10, 2015

Source:

University of Colorado Anschutz Medical Campus

Summary:

Para ilmuwan telah menemukan spesies baru hominin , makhluk kecil dengan otak yang  kecil yang membuka pintu bagi  cara baru berpikir tentang nenek moyang kita .

...... " Kami menemukan orang dewasa dan anak-anak di dalam gua yang tergabung dalam genus Homo tapi sangat berbeda dari manusia modern, " kata CU Denver Associate Professor of Anthropology Charles Musiba , PhD , yang mengambil bagian dalam konferensi pers Kamis di dekat penemuan dalam Rising Star Cave di Cradle of Humankind World Heritage Site outside Johannesburg , Afrika Selatan . " Mereka sangat mungil dan memiliki ukuran otak simpanse . Satu-satunya hal yang sama kita tahu adalah apa yang disebut ` hobbit ' dari Pulau Flores di Indonesia . "...........more

Ancient ancestor of humans with tiny brain discovered

Homo naledi raises intriguing questions
about our evolutionary past

Date:

September 10, 2015

Source:

University of Colorado Anschutz Medical
Campus

Summary:

Scientists have discovered a new species
of hominin, a small creature with a tiny brain that opens the door to a new way
of thinking about our ancient ancestors.

.................

An international team of scientists,
including one from the University of Colorado Denver and another from the
University of Colorado Anschutz Medical Campus in Aurora, announced the
discovery Thursday of a new species of hominin, a small creature with a tiny
brain that opens the door to a new way of thinking about our ancient ancestors.

The discovery of 15 individuals, consisting
of 1,550 bones, represents the largest fossil hominin find on the African
continent.

"We found adults and children in
the cave who are members of genus Homo but very different from
modern humans," said CU Denver Associate Professor of Anthropology Charles
Musiba, PhD, who took part in a press conference Thursday near the discovery
inside the Rising Star Cave in the Cradle of Humankind World Heritage Site
outside Johannesburg, South Africa. "They are very petite and have the
brain size of chimpanzees. The only thing similar we know of are the so-called
`hobbits' of Flores Island in Indonesia."

Homofloresiensis
or Flores Man was discovered in 2003. Like this latest finding, it stood 3.5
five feet high and seems to have existed relatively recently though the exact
age is unknown.

Caley Orr, PhD, an assistant professor
of cell and developmental biology at the University of Colorado School of
Medicine, analyzed the fossil hands.

"The hand has human-like features
for manipulation of objects and curved fingers that are well adapted for
climbing," Orr said. "But its exact position on our family tree is
still unknown."

The new species has been dubbed Homonaledi
after the cave where it was found -- naledi means `star' in the local South
African language Sesotho.

One of the most intriguing aspects of
the discovery is that the bodies appear to have been deposited in the cave
intentionally. Scientists have long believed this sort of ritualized or
repeated behavior was limited to humans.

The team of 35 to 40 scientists was led
by Lee Berger, research professor in the Evolutionary Studies Institute at the
University of Witwatersrand in South Africa. It was supported by the National
Geographic Society and the National Research Foundation. The October issue of National
Geographic magazine will feature the discovery as its cover story. It will also
be the subject of a NOVA/National Geographic Special airing Sept. 16.

Getting inside the Dinaledi chamber of
the remote cave system was difficult, requiring the help of six `underground
astronauts,' who squeezed through a 7-inch wide gap to reach the remains.

"The chamber has not given up all
of its secrets," said Berger, a National Geographic Explorer-in-Residence.
"There are potentially hundreds if not thousands of remains of H. naledi
still down there."

The announcement coincides with the
publication of two studies about the new species in the journal eLife,
co-authored by Musiba and Orr.

In it, the researchers try to
place Homonaledi in context with other species. Generally speaking,
they say, there is an assumption that any new group of fossils must belong to
an existing species.

But it's not that simple here.

"Assigning these remains to any
known species of Homo is problematic," the study said.
"While Homo(naledi) shares aspects of cranial and mandibular
morphology with Homohabilis,Homorudolfensis, Homoerectus, MP
Homo and Homosapiens, it differs from all of these taxa in
its unique combination of derived cranial vault, maxillary, and mandibular
morphology."

The study suggests that Homonaledi
most closely resemblesHomoerectus with its small brain and body size.
Yet it also resembles Australopithecus which highlights its own uniqueness.

Complicating matters is the fact that
researchers still don't know the exact age of the fossil site.

"If these fossils are late Pliocene
or early Pleistocene, it is possible that this new species of small-brained,
earlyHomorepresents an intermediate between Australopithecus andHomoerectus,"
the study said.

That would also make the new species
very old.

But if the fossils are more recent, they
theorize, it raises the possibility that a small-brained Homolived
in southern Africa at the same time as larger brained Homospecies
were evolving.

"This raises many questions,"
Musiba said. "How many species of human were there? Were their lines that
simply extended outward and then disappeared? Did they co-exist with modern
humans? Did they interbreed?"

Homonaledi
has a chest similar to a chimpanzee and hands and feet proportionate with
modern humans, though with curved fingers.

"They would have had great climbing
ability," said Musiba. "The oldest adults were about 45 and the
youngest were infants."

He described poring over the bones late
at night as akin to `hitting the jackpot.'

"You just didn't want to go home
because it was so exciting," he said. "I felt like a kid in a candy
store." The find represents another milestone in Musiba's efforts to
advance the understanding of our earliest human relatives.

As director of CU Denver's Tanzania
Field School, he takes groups of students each year to gain hands-on experience
working in and around the famed Laetoli hominin footprints site and Olduvai
Gorge where some of the oldest hominin remains have been found.

Not long ago, they discovered ancient
footprints of lions, rhinos and antelopes near those of the early hominins.

And last year, Musiba was appointed to
an international team of advisors dedicated to building a museum complex in
Tanzania to showcase a collection of 70 hominin footprints, estimated at 3.6
million years old. They are considered the earliest example of bipedalism among
hominins.

Musiba said the Rising Star expedition
was notable for getting so many anthropologists to work together.

"Anthropology can be a cut-throat
profession with all these scientists scrambling for limited resources," he
said. "To me one of the most exciting aspects of this research was the
collaborative nature of it."







Story Source:

The above post is reprinted from materials provided byUniversity of Colorado Anschutz
Medical Campus. The original item was written by David
Kelly. Note: Materials may be edited for content and length.







Journal Reference:

1.   
Paul HGM Dirks, Lee R Berger, Eric M
Roberts, Jan D Kramers, John Hawks, Patrick S Randolph-Quinney, Marina Elliott,
Charles M Musiba, Steven E Churchill, Darryl J de Ruiter, Peter Schmid, Lucinda
R Backwell, Georgy A Belyanin, Pedro Boshoff, K Lindsay Hunter, Elen M
Feuerriegel, Alia Gurtov, James du G Harrison, Rick Hunter, Ashley Kruger,
Hannah Morris, Tebogo V Makhubela, Becca Peixotto, Steven Tucker. Geological
and taphonomic context for the new hominin speciesHomo naledifrom the Dinaledi
Chamber, South Africa. eLife, 2015; 4 DOI:10.7554/eLife.09561

http://www.sciencedaily.com/releases/2015/09/150910084610.htm

READ MORE

Tulang dari Flores menunjukkan ciri-ciri dari sindrom Down, bukan manusia 'Hobbit' baru--T-REC semarang--komunitas reptil semarang

08.24

Tulang dari Flores menunjukkan ciri-ciri dari sindrom Down

SILAHKAN MENGGUNAKAN " MESIN TRANSLATE "..GOOGLE TRANSLATE 
DISAMPING KANAN INI.............

PLEASE USE ........ "TRANSLATE MACHINE" .. GOOGLE TRANSLATE BESIDE RIGHT THIS

.................

Tulang dari Flores  menunjukkan ciri-ciri dari sindrom Down, bukan manusia 'Hobbit' baru

Pada Oktober 2004, penggalian fragmentaris rangka dari pulau Flores Indonesia menghasilkan yang disebut "yang paling penting evolusi manusia selama 100 tahun." Penemu yang dijuluki menemukan Homo floresiensis, nama saran  sebelumnya  dari spesies manusia tak dikenal............

Flores bones show features of Down syndrome, not a new 'Hobbit' human

Date:

August 4, 2014

Source:

Penn State

Summary:

In October 2004, excavation of fragmentary skeletal remains from the island of Flores in Indonesia yielded what was called 'the most important find in human evolution for 100 years.' Its discoverers dubbed the find Homo floresiensis, a name suggesting a previously unknown species of human.

..............................

In October 2004, excavation of fragmentary skeletal remains from the island of Flores in Indonesia yielded what was called "the most important find in human evolution for 100 years." Its discoverers dubbed the find Homo floresiensis, a name suggesting a previously unknown species of human.

Now detailed reanalysis by an international team of researchers including Robert B. Eckhardt, professor of developmental genetics and evolution at Penn State, Maciej Henneberg, professor of anatomy and pathology at the University of Adelaide, and Kenneth Hsü, a Chinese geologist and paleoclimatologist, suggests that the single specimen on which the new designation depends, known as LB1, does not represent a new species. Instead, it is the skeleton of a developmentally abnormal human and, according to the researchers, contains important features most consistent with a diagnosis of Down syndrome.

"The skeletal sample from Liang Bua cave contains fragmentary remains of several individuals," Eckhardt said. "LB1 has the only skull and thighbones in the entire sample."

No substantial new bone discoveries have been made in the cave since the finding of LB1.

Initial descriptions of Homo floresiensis focused on LB1's unusual anatomical characteristics: a cranial volume reported as only 380 milliliters (23.2 cubic inches), suggesting a brain less than one third the size of an average modern human's and short thighbones, which were used to reconstruct a creature standing 1.06 meters (about 3.5 feet tall). Although LB1 lived only 15,000 years ago, comparisons were made to earlier hominins, including Homo erectus and Australopithecus. Other traits were characterized as unique and therefore indicative of a new species.

A thorough reexamination of the available evidence in the context of clinical studies, the researchers said, suggests a different explanation.

The researchers report their findings in two papers published today (Aug. 4) in the Proceedings of the National Academy of Sciences.

In the first place, they write, the original figures for cranial volume and stature are underestimates, "markedly lower than any later attempts to confirm them." Eckhardt, Henneberg, and other researchers have consistently found a cranial volume of about 430 milliliters (26.2 cubic inches).

"The difference is significant, and the revised figure falls in the range predicted for a modern human with Down syndrome from the same geographic region," Eckhardt said.

The original estimate of 3.5 feet for the creature's height was based on extrapolation combining the short thighbone with a formula derived from an African pygmy population. But humans with Down syndrome also have diagnostically short thighbones, Eckhardt said.

Though these and other features are unusual, he acknowledged, "unusual does not equal unique. The originally reported traits are not so rare as to have required the invention of a new hominin species."

Instead, the researchers build the case for an alternative diagnosis: that of Down syndrome, one of the most commonly occurring developmental disorders in modern humans.

"When we first saw these bones, several of us immediately spotted a developmental disturbance," said Eckhardt, "but we did not assign a specific diagnosis because the bones were so fragmentary. Over the years, several lines of evidence have converged on Down syndrome."

The first indicator is craniofacial asymmetry, a left-right mismatch of the skull that is characteristic of this and other disorders. Eckhardt and colleagues noted this asymmetry in LB1 as early as 2006, but it had not been reported by the excavating team and was later dismissed as a result of the skull's being long buried, he said.

A previously unpublished measurement of LB1's occipital-frontal circumference -- the circumference of the skull taken roughly above the tops of the ears -- allowed the researchers to compare LB1 to clinical data routinely collected on patients with developmental disorders. Here too, the brain size they estimate is within the range expected for an Australomelanesian human with Down syndrome.

LB1's short thighbones not only match the height reduction seen in Down syndrome, Eckhardt said, but when corrected statistically for normal growth, they would yield a stature of about 1.26 meters, or just over four feet, a figure matched by some humans now living on Flores and in surrounding regions.

These and other Down-like characteristics, the researchers state, are present only in LB1, and not in the other Liang Bua skeletal remains, further evidence of LB1's abnormality.

"This work is not presented in the form of a fanciful story, but to test a hypothesis: Are the skeletons from Liang Bua cave sufficiently unusual to require invention of a new human species?" Eckhardt said.

"Our reanalysis shows that they are not. The less strained explanation is a developmental disorder. Here the signs point rather clearly to Down syndrome, which occurs in more than one per thousand human births around the world."

Additional context is available on the authors' website at www.LiangBuaCave.org.

---

Story Source:

The above story is based on materials provided by Penn State. The original article was written by David Pacchioli. Note: Materials may be edited for content and length.

---

Journal References:

1. Maciej Henneberg, Robert B. Eckhardt, Sakdapong Chavanaves, and Kenneth J. Hs. Evolved developmental homeostasis disturbed in LB1 from Flores, Indonesia, denotes Down syndrome and not diagnostic traits of the invalid species Homo floresiensis. PNAS, 2014; DOI: 10.1073/pnas.1407382111
2. Robert B. Eckhardt, Maciej Henneberg, Alex S. Weller, and Kenneth J. Hs. Rare events in earth history include the LB1 human skeleton from Flores, Indonesia, as a developmental singularity, not a unique taxon. PNAS, 2014; DOI: 10.1073/pnas.1407385111

http://www.sciencedaily.com/releases/2014/08/140804151510.htm

 

READ MORE