A skull of Homo erectus, dated to about 1.55 million years ago, is presented to the media by senior research scientist Dr. Frederick Manthi during a press conference held at the National Museums of Kenya in Nairobi, Aug. 9, 2007. (Xinhua/Reuters Photo) Photo Gallery>>>

    BEIJING, Aug. 9 (Xinhuanet) -- New research of fossils discovered in Africa challenges the old theory on how early humans evolved, according to Thursday's journal Nature.

    The research by famed paleontologist Maeve Leakey in Kenya shows our family tree is more like a wayward bush with stubby branches, calling into question the evolution of our ancestors.

    In 2000, Leakey found an old Homo erectus complete skull within walking distance of an upper jaw of the Homo habilis, and both dated from the same general time period. That makes it unlikely that H. erectus evolved from Homo habilis, researchers said.

    The old theory was that the first and oldest species in our family tree, Homo habilis, evolved into Homo erectus, which then became us, Homo sapiens.

    Leakey and colleagues reported in Nature that those two earlier species lived side-by-side about 1.5 million years ago in parts of Kenya for at least half a million years.

    This discredits the chief theory of man's early evolution — that one of those species evolved from the other.

    The two species lived near each other, but probably didn't interact, each having its own "ecological niche," said Fred Spoor, a professor of evolutionary anatomy at the University College in London. "Homo habilis was likely more vegetarian while Homo erectus ate some meat," he said.

    For the past few years there has been growing doubt and debate about whether Homo habilis evolved into Homo erectus. Scientists still have different opinions about it.

    (Agencies)

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