Wednesday, August 13, 2014

Walking: Touching the Ground of Human Nature

In the book of Genesis we have the beautiful  image of  God: “walking in the cool of the evening.”  Where are Adam and Eve, the first humans, when God is out for his evening walk, by the way?  Aren’t they hiding?

When I was a child growing up in Vancouver I used to go for walks by myself and I took to walking greater and greater distances, and then I got a bike, and for years I rode further and further in all directions.  It’s often the case that once you can go somewhere you just  end up  going there.  That’s what happened when we started to walk.

 Walking on hind legs, that so human of characteristics, proceeded humans by at least six million years. The first walkers, called Australopithecus, had brains the same size as the chimpanzees living today.

  In the story of Genesis, it is said that humans were created in God’s image.  Well, the story’s got a point.  One could argue that the invention of automobiles and T.V.  have led to virtual epidemics of heart disease, diabetes, and obesity - all because they have replaced walking.

 One hundred years ago people walked an average of three miles a day.  Now people drive everywhere.  There is plenty of medical and scientific evidence that regular walking keeps you healthier, prolongs life and keeps your mind in top shape.

Our prehistoric  hunter-gatherer ancestors were accomplished walkers, and could easily walk an average of twelve miles a day.  They were taller, healthier and longer-lived than  the neolithic  populations that mostly replaced them starting around  ten thousand years ago.  When humans domesticated plants and animals  and started living in permanent dwellings,  we may have gained in access to food and energy but we lost something in terms of health and fitness.

Back before humans were even on the scene, six million years ago there was severe climate change over the Earth.  The African equatorial rainforests were shrinking, and  grasslands, savannas, and deserts were taking their place.  Lakes and waterholes were drying up.

 Because the traditional habitat of the great Apes - the rainforest - was shrinking, the  ability to walk more efficiently on hind legs would have been an asset for the first species of hominid, Australopithecus.  The hypothesis that climate change drove the evolution of walking is one championed by Anthropologist Clive Finlayson, in his book  The Improbable Primate.

As hominids evolved over millions of years their abilities to walk longer distances increased.   Archaeologists have found the remains of hominids all over east Africa, and the  much more recent remains of our closest ancestors  Homo Erectus in  Europe, Asia, the Middle East, Indonesia and China.  

The hominid line that we came from were such good walkers that they were able to spread out of Africa when none of the other hominid types could.  

As humans we pride ourselves on our brains and our technology.
Without free hands we couldn’t have made and carried tools, we couldn’t have cut  the meat of predator kills that gave us the extra energy we needed for our bigger brains.

Walking was an essential precondition of talking, because the upright posture freed the lungs and the breath to find a rhythm independent of quadruped locomotion. And, an upright posture lent itself to more expressiveness with the hands and this may have led to more conscious control over communication and then, eventually to spoken language. This process would have taken millions of years to unfold.  

Walking long distances made group cohesion important and was probably the impetus for the growth in hominid brain size.  Walking long distances on a seasonal basis would have challenged our memory systems.  Can we remember where that old water hole was or understand the geography of a place never-before-seen?

Walking long distances would also bring our hominid ancestors in contact with other hominid groups possibly relatives, possibly enemies.  Bigger brains would have been an advantage to keep track of bigger groups of hominids now, not just a small group of apes in the forest.

Once our ancestors could walk migration would be an important option for many reasons:   Escaping droughts, expanding range, finding new environments, following migrating game, and seeking other hominid groups or escaping from them.  

Migration as a very challenging feat for social coordination.  You’ve got to pick up very few possessions and go together.   You and your group may be travelling for  weeks or months over rarely or never-before seen lands;  You will need scouts to find the way or detect dangers;  you need to be able to act collectively at a moments notice  and continue to act as a collective in varying circumstances.  This is a consequence of climate change and walking away from the forest.

Apes live in the forest and the forest provides everything for them.  For much of their time they live as individuals pursuing their individual wants and needs within their group.  Apes do not do migration well.  If the forest dies out where they live they will die with it.  Their ability to act collectively is severely limited compared to humans.
Darwin’s theory of Evolution  is an explanation of how changes in an organism’s environment lead to differential survival in offspring.  If  an animal figures out a means of getting to all kinds of  different environments, then it’s  opened up a huge range of possibilities to exploit, as well as a huge range of conditions that will come to challenge and shape new behaviours over the span of time.

Think about birds, how through a hundred million years of evolution the adaptation of flying has allowed them to range over the entire Earth, from above Mt Everest to every Continent including Antarctica and then to the vast oceans.  

It took humans less than a million years to walk from Africa to South America.   By walking we have entered almost all the environments that were opened to us and we have developed specialized abilities to live and to thrive in each and every one of them from the Australian outback to the frozen wastes of the Canadian North.

The interesting thing about humans is that even though we live in all kinds of different places and environments we are still just one species, because in some ways we have stayed connected.  We are still busy exchanging cultural and genetic material all the time.

By allowing hominids access to  so many different kinds of environments, walking challenged our prehistoric ancestors  to maximize brain power and cooperative abilities.  Walking is so basic that it is taken for granted, but walking is the basic behaviour that forged human nature.

Nowadays, I imagine,  writing Genesis for a modern audience, we would see God arriving in a chauffeur driven stretch limo.  Since Neolithic times God has been pictured on thrones and chariots, so why not an automobile?

 Of course we are talking about origins here, so putting things in modern dress is reversing the sequence of events.  In the beginnings of human evolution we didn’t have cars, we had our two legs, and they led us here over aeons of time. Nowhere else in the Bible is God depicted walking except in the story of our origins, in the book of Genesis.

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