New Fossils Support Evidence That Humans Evolved From One Line Not Many, Wellesley Professor Says

Did humans’ earliest ancestors split into multiple lineages early on, or are all early fossils part of one single lineage? That's the question at the center of an ongoing debate in the field of anthropology about the origin and early evolution of our genus, Homo.

The recent discovery of a set of fossils in northern Kenya prompted some scientists to declare that the fossils are “the most compelling evidence yet for multiple lines of evolution in our genus, Homo,” as reported in the New York Times. However, Wellesley’s Adam Van Arsdale, assistant professor of anthropology, is not convinced. On the contrary, Van Arsdale told Scientific American, “I tend to see this new evidence as making it harder to reject the idea of a single evolving lineage."

Van Arsdale, who has been involved with excavations at Dmanisi Hominid Archeological site in the Kvemo Kartli region of the country of Georgia, explained to Scientific American that the new Kenyan fossils show features in common with Homo erectus fossils from Dmanisi. He says this links early Homo in Africa to Homo erectus in Georgia. In his view, the newly discovered fossils (called habilis/rudolfensis) and Homo erectus belong to one lineage.

“My initial take on [the habilis/rudolfensis] fossils is that they fill an important gap, drawing connections between two somewhat exceptional specimens and a broader evolutionary picture of change in early Homo,” Van Arsdale wrote on his blog.

Van Arsdale, a biological anthropologist who specializes in paleoanthropology, has focused his research on the pattern of evolutionary change in humans over the past two million years, with an emphasis on the early evolution and dispersal of our genus, Homo.

For multiple perspectives on the debate about our early evolution, read “Kenyan Fossils Rekindle Debate over Early Human Diversity” in Scientific American. For more about Professor Van Arsdale, read a longer version of this story on the Wellesley College News web site.