Early man began to walk on two feet because of rocky terrain and not climate change, according to a new study.
Researchers have said that 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.
Hominins, our early ancestors, 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 Ascent of Man: It was previously thought that climate change and a
reduction in tree cover forced early man to stand up, but now experts
believe the rocky African landscape played a far more significant role
The York research challenged the
traditional theory that suggested our early forebears were forced out of
the trees and onto two feet when climate change reduced tree cover.
Dr Isabelle Winder, from the Department of Archaeology at York and one of the paper’s authors, said:
'Our research shows that bipedalism may have developed as a response to
the terrain, rather than a response to climatically-driven vegetation
changes.
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 has suggested that the hands and arms of upright hominins were
then left free to develop improved 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.
Dr Winder said:
'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.
'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 findings were published in the journal Antiquity.
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