Wednesday, November 23, 2011

How did the human race evolve? What happened to the skeleton?

Based on the second part of your question, I don't think that you want social and cultural evolutionary changes.  I'll stick with a few changes that have happened specifically to the human skeleton.  


Foot changes: Humans move via bipedal motion.  That means our feet have to have changed in order to maximize the efficiency of that kind of movement.  Our feet have evolved in order to bear the full weight of our bodies.  Other primates still move primarily on four limbs, so their feet are not structured to constantly bear the full load.  A specific structural change that can be seen is an enlarged heel in human skeletons.  Also, humans have much shorter toes than other primates.  That's because our feet are for walking, not for grasping. 


Hip changes: Hip changes have also occurred to further allow humans to walk upright.  Human hips tend to be shorter and broader than other species.  That shape change in turn caused the vertebral column to be located closer to the hips.  


Knee changes: This change reads almost identical to hip changes.  The knee joint is slightly enlarged in order to further allow bipedal walking.  Because all of our weight is distributed on two "platforms," human skeletons have been beefed up in the lower body joint areas to take on the increased load.  

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