Rise of the Bipeds

June 7, 2010

Torah Kachur

Thankfully a few million years ago, a hominid ancestor walked through volcanic ash.  A pretty unremarkable event when you think about it - ancient hominids probably wandered around quite a bit, hardly something to get ecstatic about.


Except, these footprints have been preserved almost perfectly.  The Laetoli footprints have been around for 3.6 million years, and modern day humans discovered them 30 years ago.  When they were discovered, anthropologists around the world had a little eureka moment because, ta daaaa, the main conclusion is that these footprints represent the first evidence of bipedal locomotion - walking on two legs.


One of the single-most important transitions in human evolution was the transition between quadripeds - or four-legged - to bipedal locomotion.  This is mostly because walking on two legs allowed human ancestors more range of motion with their arms and increased dexterity with the hands.  Also, these hominids could now see long distances through the African grasslands - possibly giving them better hunting skills.  In other words, walking on two legs was pretty neat-o.


But, like all of evolution, a human ancestor didn't just wake up one day and become bipedal.  The transition between quadripedal, knuckle-walking and then finally bipedalism has become the subject of a very long-winded and drawn out debate amongst anthropologists (and the rest of us intelligentia that know humans did evolve from apes).  Now, new biomechanical research suggests that these Laetoli footprints were made by an erect gait, not the crouching over style of walking that was thought to exist back then.

        Science in Seconds Blog by Torah Kachur Australopithecus afarensis Laetoli footprints

The most likely suspect for leaving these footprints is Australopithecus afarensis, or Lucy, whose fossils show curved fingers and toes that probably suited this ancient human to a life in the trees.  But, Lucy's pelvic angle and leg structure also would have allowed bipedal movement on land.  Therefore, this new research adds a bit to the human origin puzzle - Lucy was indeed a transition species that liked hanging in trees as well as strolling around the grasslands.


Who said footprints in the sand were fleeting?


       Science in Seconds Blog by Torah Kachur footprints in the sand



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