Stories tagged Australopithecus

Humans have longer legs than gorillas today, but this wasn't always the case.: Photo by Robert Fenton, courtesy National Gallery of Art and Victoria and Albert Museum

Early human ancestors, called Australopithecines (AW-stroh-la-PITH-eh-scenes), had short legs. Scientists have long believed this was a hold-over from even earlier species which had lived in trees. But now biologist David Carrier of the University of Utah argues the short legs were used to help them fight.

Short legs give a body a lower center of gravity, and makes it harder to push over. Living apes with short legs, like gorillas, tend to be more aggressive, while long-legged apes, like gibbons, are more docile.

Of course, humans don’t have such short legs anymore. Herman Potzner of Washington University in St. Louis proposes later human species evolved long legs to save energy. His studies of various animals show that that longer a creature’s legs, the less energy they use. Around 2 million years ago, something happened in human evolution that made the fighting advantage of short legs less important than the energy savings of long legs.

Tags : evolution, apes, Australopithecus, human evolution

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Baby girl Lucy: Image from Wikipedia

Lucy-like fossil is older and more complete

The fossil including an entire skull, torso, shoulder blade and various limbs was discovered at Dikaka, some 400 kms northeast of the capital Addis Ababa near the Awash river in the Rift Valley.

"The finding is the most complete hominid skeleton ever found in the world," Zeresenay Alemseged, head of the Paleoanthropological Research Team, told a news conference. Reuters

The fossil has been named "Selam", which means peace in Ethiopia's official Amharic language.

Zeresenay said she belonged to the Australopithecus afarensis species, which includes Lucy, and is thought to be an ancestor to modern humans.

"The Dikika girl stands as one of the major discoveries in the history of palaeoanthropology," research team leader Zeresenay Alemseged said, citing the remarkably well-preserved condition of the bones, the geological age and completeness of the specimen.Cosmos Magazine

The following is the abstract of the original article describing the baby, which was authored by Zeresenay Alemseged, Fred Spoor, William H. Kimbel, René Bobe, Denis Geraads, Denné Reed and Jonathan G. Wynn, and appeared in Nature on September 20, 2006.

"Understanding changes in ontogenetic development is central to the study of human evolution. With the exception of Neanderthals, the growth patterns of fossil hominins have not been studied comprehensively because the fossil record currently lacks specimens that document both cranial and postcranial development at young ontogenetic stages. Here we describe a well-preserved 3.3-million-year-old juvenile partial skeleton of Australopithecus afarensis discovered in the Dikika research area of Ethiopia. The skull of the approximately three-year-old presumed female shows that most features diagnostic of the species are evident even at this early stage of development. The find includes many previously unknown skeletal elements from the Pliocene hominin record, including a hyoid bone that has a typical African ape morphology. The foot and other evidence from the lower limb provide clear evidence for bipedal locomotion, but the gorilla-like scapula and long and curved manual phalanges raise new questions about the importance of arboreal behaviour in the A. afarensis locomotor repertoire."

Additional reading: BBC News

Tags : evolution, Afarensis, Lucy, Australopithecus, Zeresenay Alemseged, fossil, Paleoanthropology, Selam

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