The discovery of the fragment of a fossilized jawbone from East Africa is providing a whole new insight on the evolution of Homo sapiens stressing that the impact of climate change has steered the development of our early ancestors.
It can be concluded from the discovery of a 2.8 million year old jawbone in Ethiopia that humans have appeared on Earth half a million years ago than previously anticipated. This discovered ‘broken jaw’ had 5 intact teeth and as per researchers, this discovery decisively agrees with the roots of Homo being situated in the eastern regions of Africa all the while agreeing with the hypothesis of climate change driving the major developments in various mammals which includes including our prehistoric ancestors.
The jaw’s mandible exposes that our early ancestors have branched off from the more apelike Australopithecus genus reminiscing the most renowned remains of skeletal set called ‘Lucy’.
Researchers believe that around the reign of Lucy in Ethiopia around 3.2 million years ago, the region benefitted from long rainy seasons which helped sustain the growth of various trees and an array of vegetation.
The surroundings had converted into a much drier place when Homo’s settled in the Horn of Africa with the green landscape being overtaken by an enormous, treeless spread with a small number of rivers and lakes reflecting the contemporary Serengeti plains.
The climate was indeed too harsh for survival.
The resourceful nature of Homo sapiens such as larger brains, the capability to carve stone tools and teeth suitable for chewing all kinds of food has helped them survive this period of inflexibility as researchers say.
Kaye Reed, an Arizona State University paleontologist who worked on both studies said “This early Homo could live in this fairly extreme habitat, and apparently Lucy’s species could not.”
The fossil’s age could not be established directly so radiation dating was used in estimating the era of a layer of volcanic ash and crystals approximately 30 feet below the fossil known as LD 350-1.
William Kimbel, director of Arizona State’s Institute of Human Origins, co-author of the study said “The time period between 2 (million) and 3 million years ago is one of the least-well-understood in human-origin studies.”
As odd as it may sound, but some of the natural forces which make it so tough to find archaeological specimens of a specific age makes it comparatively simple in determining the changes in the ancient climate of the Earth.
The soil which flushes out to the sea due to erosion or blown off the land by monsoon winds glides to the ocean bed forming immense layers of untouched sediment and these layers endows us with chemical clues which helps in distinguishing the eras of dryness or vegetation as researchers explain.
These layers have been used for assembling a strong record of ancient climate and theorized that it was driven by human evolution.
According to Peter deMenocal, a paleoclimatologist at Columbia University, not associated with either study said that this jaw goes back to a time of turbulent climate change inclusive of the period of the first ice age in the Northern Hemisphere.
This discovery of the jaw has been making scientist rearrange the branches of our ancestral tree.
It is evident that 3 different species of Homo existed between 2.1 to 1.6 million years ago even though not all at the same time; H. habilis, H. rudolfensis and H. erectus.
