The closest ancestors of modern-day humans (Homo sapiens) and other subspecies of the genus Homo are thought to have originated in Eastern Africa around 2.85 million years ago. Archaeologists interested in the link between the earliest members of the genus Homo and modern humans often study the migration patterns of Homo sapiens and their closest relatives to refine our evolutionary tree. The earliest record of modern-day humans dates to around 250,000 years ago, but, until recently, the earliest Homo sapiens fossil found outside of Africa was only about 120,000 years old. A recent discovery of a partially intact Homo sapiens jaw bone in Israel, however, has been dated between 177,000 and 194,000 years old.
Israel Hershkovitz of Tel Aviv University led the expedition responsible for unearthing the well-preserved jaw fragment. The fossil suggests that modern-day humans were exploring regions outside of Africa more than 55,000 years earlier than previously thought. This finding adds further complications to the accepted understanding of Homo sapiens dispersal, which primarily consists of two waves of out-of- Africa migration at 100,000 and 70,000 years ago. Genetic testing indicates that modern-day humans are likely direct descendants of the second wave of Homo sapiens out-of- Africa migration.
While there may be no genetic link between today’s humans and the newly discovered fossil at the moment, this finding is critical to scientific understanding of the behavior of the earliest Homo sapiens. Scientists hope to resolve the motivation behind the earliest and seemingly sporadic episodes of out-of-Africa exploration, which are inconsistent with the two primary waves of Homo sapiens migration.
Managing Correspondent: Zachary Eriksen
Image Credit: NPR
Original Article: Science
Related SiTN Article: When did the Americas encounter the first humans?