A Missing Link In The Human Chain?

Mar 15, 2015 By Akila S, Writer Intern
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One question that has puzzled scientists for a long while is the origin of humanity.

Based on scientific studies, it has been estimated that life began on earth about 3.5 billion years. Humans have however only been around for 300,000 of these years. We can trace our ancestry to the species called hominids, and they are believed have lived around 3.5 million years. 

How do they we know this? Turns out the oldest discovered hominid fossil- called Lucy, was discovered in 1973. Her age was placed at 3.2 million years, based on carbon dating studies.

Since finding Lucy, other fossils of the hominids were discovered but they were either older than 3 million years or younger than 2.3 million years. Paleontologists had puzzled about what happened to the species and its evolution in the intervening 700,000 years that eventually led to us. They had to wait for answers until recently. 

Tracing Our Past

Humans belong to the superfamily of primates. Primates include apes, gorillas, and lemurs, with whom the genus of 'homo', shares several common features. This has been revealed by fossil discoveries. The scientific name for modern man is 'Homo Erectus' since we stand straight and walk on two feet. Strangely, almost all traces of our earliest ancestors have led us to the Rift Valley and the Afar region of Ethiopia.

Recently, on a paleontology dig in Ethiopia, Africa, researchers from Arizona State University discovered a jawbone with a few teeth that seemed to have belonged to a hominid. Further study revealed that it had indeed belonged to one of our ancestors. Amazingly it helps fill an important missing puzzle in the chain between Lucy and us. 

The Significance Of The Fossil

The jawbone dates back to 2.8 million years and bears a lot of similarity with Lucy - an Australopithecus afarensis. However, the slim molar teeth, the pattern of tooth cusps (ridges on the top of the teeth) and the shape of the mandible, resemble those of the genus Homo, and helps paleontologists fill in the stages of evolution of apes and humans which was unknown. The paleontologists hope to find more complete fossils in the same region that can give them a clearer picture of the evolutionary changes of our ancestors.

There is so much we still have to learn about our past and how we got here. The recent discovery of fossilized jawbones has certainly given us a lot to chew on!

Courtesy: Arizona State University