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Researchers from the University of Cambridge and the University of Tubingen,Germany have carried out a new study which has investigated if our human ancestors were similar to us regarding the shape and the size of their bodies. The research discovered that this diversity was present as far back as two million years ago.
“What we’re seeing is perhaps the beginning of a unique characteristic of our own species. It is the origin of diversity,” said study co-author Jay Stock, of the Department of Archaeology and Anthropology at the University of Cambridge.
This is the first research that has compared the body size of early humans. The scientists used fossils from 1.5 million to 2.5 million years ago.
“It’s possible to interpret our findings as revealing that there were either multiple species of early humans, such as Homo ergaster, Homo habilisand Homo rudolfensis, or one extremely diverse species. This fits well with recent cranial evidence for the extraordinary diversity among early members of the genus Homo”, said the researcher.
The study also revealed that early humans had heights ranging from 4’8” to nearly six feet tall, which is very similar to the average of height of the modern human.
One of the most credible theories of our evolution is that genus Homo evolved from an early human ancestor, which had a small stature, and then become the taller, heavier Homo erectus, which also had longer legs. Homo erectus was thus able to migrate beyond Africa and settle in Eurasia. Until now, the geographic origin and the timing of the larger body size has remained unknown.
According to the new study, the main increase in body size occurred tens of thousands of years after Homo erectus left Africa. Before then, our ancestors were rarely over 5 feet tall or particularly heavy in body mass, said the co-author of this study, which was published in the March 27 issue of the Journal of Human Evolution.
The study also discovered that the shift to taller humans happened in one place in particular, the Koobi Fora region in Kenya, around 1,7 milion years ago. “That means we can now start thinking about what regional conditions drove the emergence of this diversity, rather than seeing body size as a fixed and fundamental characteristic of a species”, Stock concluded.
Image Source: Io9
