Did you know that humans, or Homo sapiens, are the only human species still in existence?
The process of how humans came to be today is a long one – an estimated 2.5 to 4 million years in the making! And, just because human evolution began in Africa, does not mean that it stayed there. Based on fossil evidence, anthropologists believe modern humans started moving out of Africa 100,000 years ago.
But a new discovery by a group of researchers at Tel Aviv and Haifa University is challenging the timeline. Recently, an adult upper jawbone with teeth and stone tools (most of which are blades and objects with a sharpened point) were uncovered at the Misliya caves in Israel.
The “Out of Africa” theory describes the migration of Homo sapiens out of Africa.
According to the theory, there have been at least two migration events in which modern humans dispersed from their area of origin. Anthropologists agree that modern humans came to be in Africa around 160,000 to 200,000 years ago and began migrating out 100,000 years ago. They could have left their homes due to changes in climate or competition due to a scarcity of food.
Before this discovery, the earliest human remains were also found in Israel, in the Skhul and Qafzeh caves. However, this new discovery dates even farther back, from 170,000 to 190,000 years ago. This is around the same time when humans first appeared in Africa. This reveals that Homo sapiens may have left Africa 50,000 years earlier than previously thought.
We should clarify that so far we are talking about modern humans (Homo sapiens). There were other hominids such as Homo habilis and Homo erectus that migrated out of Africa earlier and died out. The Neanderthals were one of the major species still in existence when modern humans appeared outside Africa.
The recent finding of the jawbone (named Misliya-1) is significant as it is thus far the earliest modern human remains to be found outside of Africa.
Researchers are certain the jawbone belongs to a modern human as it retains characteristics found in modern humans. However, they caution us that this modern human would not have looked anything like us and could even have been part of a group that died out. The jawbone also shows some characteristics belonging to Neanderthals which is evidence of cross-breeding between the two groups. The inhabitants of the once vast Misliya cave (before it collapsed) are said to be hunters, which explains the stone tools found.
While the discovery reveals a lot, some questions still linger... Were those traveling to Israel able to do so because of a change in climate? Do traits that are influenced by the climate affect human evolution? What led to the demise of those living in the Misliya caves? Also, there is some discussion about what defines a modern human and if one sample size is enough to make a conclusion.
Either way, with each new jaw-dropping discovery, researchers are beginning to piece together the story of human evolution!
Sources: Washington Post, Sciencemag, Time, Newatlas, israel21c.org, Khan Academy