A new study by archaeologists at the University of York says our upright gait may have its origins in the rugged landscape of East and South Africa which was shaped during the Pliocene epoc...
A new study by archaeologists at the University of York says our upright gait may have its origins in the rugged landscape of East and South Africa which was shaped during the Pliocene epoch by volcanoes and shifting tectonic plates. The York research challenges traditional hypotheses which suggest our early forebears were forced out of the trees and onto two feet when climate change reduced tree cover.
Humans are unique among living primates in that walking bipedally — on two feet — is humans' chief mode of locomotion. This upright posture freed their hands up for using tools, one of the key factors behind humans' domination of the planet.Among the earliest known relatives of humanity definitely known to walk upright was Australopithecus afarensis, the species including the famed 3.2-million-year-old "Lucy" (image below). Australopithecines are the leading candidates for direct ancestors of the human lineage, living about 2.9 million to 3.8 million years ago in East Africa.
Hominins, our early forebears, would have been attracted to the terrain of rocky outcrops and gorges because it offered shelter and opportunities to trap prey. But it also required more upright scrambling and climbing gaits, prompting the emergence of bipedalism.The study, 'Complex Topography and Human Evolution: the Missing Link', was developed in conjunction with researchers from the Institut de Physique du Globe in Paris.
"Our research shows that bipedalism may have developed as a response to the terrain, rather than a response to climatically-driven vegetation changes," said Dr Isabelle Winder, from the Department of Archaeology at York and one of the paper's authors. "The broken, disrupted terrain offered benefits for hominins in terms of security and food, but it also proved a motivation to improve their locomotor skills by climbing, balancing, scrambling and moving swiftly over broken ground - types of movement encouraging a more upright gait."
The research suggests that the hands and arms of upright hominins were then left free to develop increased manual dexterity and tool use, supporting a further key stage in the evolutionary story. The development of running adaptations to the skeleton and foot may have resulted from later excursions onto the surrounding flat plains in search of prey and new home ranges.
"The varied terrain may also have contributed to improved cognitive skills such as navigation and communication abilities, accounting for the continued evolution of our brains and social functions such as co-operation and team work," said Winder. "Our hypothesis offers a new, viable alternative to traditional vegetation or climate change hypotheses. It explains all the key processes in hominin evolution and offers a more convincing scenario than traditional hypotheses."
The Daily Galaxy via University of York
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