Monday, April 5, 2010

Missing link found: 2 million year old fossil could rewrite human evolution

The discovery of a nearly-complete early human skeleton is set to revolutionise scientists' understanding of human evolution. Homo habilis lived 2.0-1.6 million years ago and had a wide distribution in Africa Photo: SPL

A MISSING link between humans and their apelike ancestors has been discovered near Johannesburg in an area known as the Cradle of Humanity.

The new species of hominid, the evolutionary branch of primates that includes humans, will be revealed when the 2-million-year-old skeleton of a child is unveiled this week.

Scientists believe the almost-complete fossilised skeleton belonged to a previously unknown type of early human ancestor that may have been an intermediate stage as ape-men evolved into the first species of advanced humans, Homo habilis.

Experts who have seen the skeleton say it shares characteristics with Homo habilis, whose emergence 2.5 million years ago is seen as a key stage in the evolution of our species. It is thought it will be identified as a species that fits somewhere between Australopithicus and Homo habilis.

The discovery could help rewrite the history of human evolution by filling in crucial gaps in the scientific knowledge.

Most fossilised hominid remains are little more than scattered fragments of bone, so the discovery of an almost-complete skeleton will allow scientists to answer key questions about what our early ancestors looked like and when they began walking upright.

The skeleton was found by Professor Lee Berger, of the University of the Witwatersrand, while exploring cave systems in the Sterkfontein region of South Africa.

The find is considered so significant that Jacob Zuma, the South African President, has visited the university to see the fossils and a media campaign with television documentaries is planned. ...

via Scientists on tenterhooks as 2-million-year-old skeleton takes a bow.

Some religiously-inspired opponents of evolution theory use the patchy fossil record to argue that humans did not evolve from primates.

But rare fossil finds like the new skeleton from the Malapa caves in Sterkfontein, South Africa, give anthropologists the opportunity to gain huge insights into how our prehistoric ancestors lived and looked.

Africa is now widely accepted as the birthplace of mankind as simple primates evolved into the common ancestor we share with the great apes such as Chimpanzees and Gorillas.

Around 3.9 million years ago a species known as Australopithecus afarenus emerged, which was apelike but also shared certain characteristics with modern humans like the ability to walk upright on two legs.

This bipedalism, however, has remained one of the most contentious issues in human evolution and the evidence for exactly when human ancestors moved onto two feet to walk around remains a hotly debated subject.

The first truly human-like species is thought to have first appeared around 2.5 million years ago in southern and eastern Africa.

Homo habilis, as it has been named, had a 50% larger brain capacity than its predecessors and was the earliest species to be placed by scientists in the genus Homo due to its human-like characteristics. ...

With an almost-complete skeleton, however, it will be possible to determine whether this early ancestor of humans climbed trees or lived on open grassland and if it stood upright or used its arms to assist when walking.

Armed with this kind of detail, scientists should be able to make far more conclusive statements about how our own species evolved.

via Telegraph

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