A scientific breakthrough took place in Ethiopia where researchers found a jawbone probably belonging to one of the very first humans. It seems that the specimen lived 400,000 years earlier than the up until now considered first human. The jawbone is 2.8 million years old.
Professor William Kimbel, director of Arizona State University’s Institute of Human Origins explained that:
“Previously, the oldest fossil attributed to the genus Homo was an upper jaw from Hadar, Ethiopia, dated to 2.35m years ago.”
This discovery might give some insight on what made apes climb down the trees to live life on the ground.
Brian Villmoare, a professor at the University of Nevada in Las Vegas said that the discovered jawbone could be linked to the hominin (human-like primate) that lived 3.2 million years ago, called “Lucy”, whose remains were discovered in the same area as this 2.8 million year old lower jawbone. Vilmoare considers that this newly discovered jaw has a “mix of primitive and advanced features” which made it a “good transitional form between Lucy and later humans.”
The recently discovered fossil is the left portion of a primitive lower jawbone. It was found in the Ledi-Geraru research area. Five teeth were attached to the bone piece. The molar teeth, situated posteriorly, have smaller proportions compared to those belonging to other hominis that once populated the area and are one of the key features that discerns humans from their primitive ancestors.
The primitive jawbone found in Ethiopia might help scientists understand what made apes climb down from trees and decide to remain on the ground.
The findings of another recent study published in the Science journal indicate that this change could have been caused by environmental factors. The study consisted of the analysis of a fossilized plant and the animal life characteristic to that area which, once a dense rainforest, became dry grassland. This event could have encouraged the apes do descend and explore their surroundings.
Being exposed to a new environment stimulated their brain. Slowly, through evolution, brain started developing and apes started using tools which lessened the teeth activity and ,with this, permitted the jawbone to shrink.
Prof. Chris Stringer of the Natural History Museum in London considers that more evidence needs to be found in order to conclude that the jawbone belonged to one of our earliest ancestors.
Image Source: CBC