The origin of man has always intrigued paleontologists and each time they decided that they have unraveled the mystery of the first human, a chance discovery pushed the truth further into the hoary past. For long, the belief had gained ground that the first man originated in eastern Africa.
The belief would have stayed un-impeached had not a group of researchers unexpectedly stumbled upon a fragmented piece of a jawbone of an unidentified species of ape, at a site in northern Africa’s Chad region, 2500 km from the Rift valley. They named the owner of the jawbone, ‘Abel’.
Abel’s remains shook they theory of human evolution to its core and set experts reconstructing all a new the course of evolution from the ape to man’s distant likeness the hominid. Abel, they now know, was someone distinctly different from the first human prototype, the Australopithecus, believed to have surfaced in eastern Africa.
Abel, and his kind, to be distinguished as Australopithecus bahrelghazali, roamed the northern part of Africa sometime between 3 million and 3.5 million years ago. It is futile to argue that Abel belonged to one of those in the eastern part of the continent and walked 2500 km into the northern fringes of the continent for unknown reason to keep away from his kinsmen. For the fledling early half-man, fighting indecisively in a brutally hostile world to keep himself in one piece, 2500 km was a physical impossibility.
Besides, there is anatomical corroboration of theory that Abel was older than the eastern African Australopithecus. Experts reconstructed the jawbone to discover that it was a combination of evolved human molar teeth with the three-root teeth of chimps and other apes. It was midway between the chimp and the human.
Scientists are still trying to place Abel in the whole history of hominid evolution. Could Abel be one of the cusp species between the chimp and the human. Till date skeletal fragments are disarmingly few and far between to arrive at a firm conclusion. But the primordial jawbone with its mixed pattern does point to such conclusion.
Till 1994, evidence of hominids older than 3.6 million years was scanty and the oldest of out known ancestor, is a short statured ape-like creative, presumably a female, belonging to a species called Australopithecus afarensis.
Paleontological researches tend to point out that the earliest hominid came from Africa and shared its ancestry with the ape.
Basing on the process of molecular evolution, molecular biologists suggest the parting of the ways between the hominids and the apes must have taken place anywhere between 5 to 7 million years ago. That period is practically unknown to fossil records.
There is no knowing how that ancestor lived and died or what the animal looked like except that it was much like the chimpangee or the gorilla. It is difficult to guess why the animal tried to be different from the apes or became bipedal. But it did turn the course of evolution by electing to be bipedal and parted ways to grow into a splendid new animal – the hominid – and then finally, us, the homosapiens.
Bipedalism set in motion enormous anatomical evolution but the receding ape features like the three-root teeth still persisted.
The transition was still at work with the afarensis – the earliest of our known ancestors.
A partial female skeleton of one of the species was discovered in Ethiopia and was nicknamed Lucy. Dated 3.18 million years, Lucy had long arms like the apes. But her pelvic and leg bones indicated that she walked. There are evidences that 3.65 million years ago Lucy’s fore fathers were largely bipedal. But trees still had a place in the gradually receding simian habits of the emerging animals. Their long powerful forearms, curved fingers and toes tell us they were tree climbers for food, shelter and defense. The growing anatomical evolution indicated by increasing bipedalism is evident from the finds from northern Kenyan sediments, specially from Kanapoi site. Two sections of the larger leg bone – the tibia – showed that the species walked upright. The formation of knee – the socket – like condolytes – is more distinctly human than simian.
It is possible that as bipedalism was increasingly becoming an established trait and habit with the new genus, several variations of hominid groups emerged only one of which came to stay.
At least two species have come to the knowledge of the experts – the Australopithecus ramidas and Ardipithecus or the ground ape.
One reason why a particular branch of apes took to bipedalism could have been dictated by exigencies of dangerous environment and forays into unfamiliar surroundings. The primordial had discovered an upright posture gave a vantage point.
Several bone fragments found in Lake Turkana’s Turkwel site turned out to be a corporal bone from a hominid, some 3.5 million years old. One of these – a piece of hand bone – suggests that the creature had enormously strong hands like the chimps or the gorilla lending grounds to presume that he was still largely a tree climber.
Paleontological findings, fragmented and partial as they are, indicate that the crucial turning point in the hominid evolution took place with the impulse of the branch of the primates to walk on ground rather than move from one tree to another.
It must have taken apes several million years earth. And even when they did do so, trees must have continued to play an important role as shelter, sources of food and defense.
A few hesitant, strained and faltering steps of the arrival, nevertheless, brought about profound anatomical changes that decisively cruised biological evolution into a fundamentally different path. It gave rise to a wonderful animal-the homosapien – who walked the earth to reach for the heavens.
