What was it that lead our distant ancestors to move from walking on four legs to walking on two ?
One of the most prevailing theories concerns changes in the climate up to 2.5 million years ago which lead to the demise of large swaths of forest in Africa. As the trees made way for open savannah, it is believed, our ancestors adapted by developing the ability to walk upright. Now however this theory has been challenged by a team of archaeologists who have suggested the change was brought about not by climate change but by geology.
Volcanic activity and shifting tectonic plates in Africa at the time could have produced uneven terrain, deep gorges and other obstacles that favor bipedalism. "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," said study co-author Isabelle Winder.
"Being four-legged has its perks. As a quadruped, your center of gravity is lower, there's less wind resistance when you're running, and, best of all, you can use your hind foot to scratch your ear."
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Source: Christian Science Monitor
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