Fully Erect 3mya
THE latest discovery, a metatarsal of Australopithecus afarensis at Hadar, Ethiopia reported in the Science (Feb 11, 2011) by Carl Ward et al. of University of Missouri, goes a long way in enlightening us about evolution of erect posture.
AUSTRALOPITHECUS (Australo = Southern, Pithecus = ape), first discovered in South Africa by Ramond Dart in 1924, is considered the first hominid ancestor of modern man, the Homo sapiens. Many species of Australopithecus are known today but the species that generated interest in human evolution the most is Australopithecus afarensis. The poster girl of the species is Lucy, discovered by Johnson in 1974 is the oldest (3.2 million year old) almost complete fossil of a hominid ancestor. Lucy's fossils account for 40% of her bones and almost 80% of her body but foot bones were conspicuous in their absence.
BEFORE the present discovery, the bio-mechanical researches of the last decade concluded that Australopithecus had a shuffling shifting gait while walking slowly; also that his foot was not arched and so it was not an efficient biped walker. Therefore, it was concluded that he enjoyed arboreal habits more than the terrestrial. All these conclusions have been reversed by the latest discovery.
WARD et al. have come to the conclusion that the species was fully bipedal as good as modern man. Their feet had arches stiffening their feet like us as opposed to apes whose feet are more flexible, suited to arboreal life. But he had strong and muscular arms useful to climb.
ARCHED foot is an important development in human evolution as it resulted in the changes in big toe to suit to erect posture, not for grasping as in apes. This observation will ultimately shed new light on other behavioural aspect associated with erect posture.
IN another development Lovejoy, who has, for more than a decade, studied the fossils of 4.5 million year old Ardipithecus ramidus (some prefer to call him Australopithecus ramidus) discovered by Tim White in 1994, has reconstructed ramidus' anatomical and behavioural history (Science Discovery, Feb 7). He has conclude that though ramidus too was bipedal, he was not as efficient as his big toe resembled apes more than man.
AUSTRALOPITHECUS (Australo = Southern, Pithecus = ape), first discovered in South Africa by Ramond Dart in 1924, is considered the first hominid ancestor of modern man, the Homo sapiens. Many species of Australopithecus are known today but the species that generated interest in human evolution the most is Australopithecus afarensis. The poster girl of the species is Lucy, discovered by Johnson in 1974 is the oldest (3.2 million year old) almost complete fossil of a hominid ancestor. Lucy's fossils account for 40% of her bones and almost 80% of her body but foot bones were conspicuous in their absence.
BEFORE the present discovery, the bio-mechanical researches of the last decade concluded that Australopithecus had a shuffling shifting gait while walking slowly; also that his foot was not arched and so it was not an efficient biped walker. Therefore, it was concluded that he enjoyed arboreal habits more than the terrestrial. All these conclusions have been reversed by the latest discovery.
WARD et al. have come to the conclusion that the species was fully bipedal as good as modern man. Their feet had arches stiffening their feet like us as opposed to apes whose feet are more flexible, suited to arboreal life. But he had strong and muscular arms useful to climb.
ARCHED foot is an important development in human evolution as it resulted in the changes in big toe to suit to erect posture, not for grasping as in apes. This observation will ultimately shed new light on other behavioural aspect associated with erect posture.
IN another development Lovejoy, who has, for more than a decade, studied the fossils of 4.5 million year old Ardipithecus ramidus (some prefer to call him Australopithecus ramidus) discovered by Tim White in 1994, has reconstructed ramidus' anatomical and behavioural history (Science Discovery, Feb 7). He has conclude that though ramidus too was bipedal, he was not as efficient as his big toe resembled apes more than man.
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