Leave your feedback Share Copy URL https://www.pbs.org/newshour/show/unearthed-skull-revises-understanding-of-human-evolution Email Facebook Twitter LinkedIn Pinterest Tumblr Share on Facebook Share on Twitter Story Transcript Research based on a 1.8 million-year-old skull shows that human evolution may have followed a straighter line than scientists previously thought. The skull, unearthed in the former Soviet republic of Georgia, is the most complete ever found of a human ancestor and marks the earliest evidence of human ancestors leaving Africa. Read the Full Transcript JUDY WOODRUFF: Now to an important finding of ancient fossils that could rewrite the latest thinking about human evolution and is the subject of scientific debate.Jeffrey Brown has the story. JEFFREY BROWN: The 1.8 million-year-old skull is the most complete ever found of a human ancestor from what's known as the human genus Homo.It was unearthed in 2005 below a medieval village in the former Soviet republic of Georgia. Now, after eight years of research, the scientists who found it say it may show that human evolution followed a more straightforward line than has been thought and that fossils currently identified as different species may actually be variations within a single species. DAVID LORDKIPANIDZE, Georgian National Museum: This new discovery shows that many features which we previously thought as variability and diversity could be lumped in one group. JEFFREY BROWN: The skull was discovered with other partial remains, marking the earliest evidence of human ancestors moving out of Africa. MAN: The species that we thought were different species in Africa now we realize probably are variants of the same species. JEFFREY BROWN: Other scientists were more cautious in making that leap, though, even as they acknowledged that the new findings, published in the journal "Science," were spectacular, indeed.