On “Becoming Human” – Part 1

Posted on January 26, 2010

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Part three of the Throwing Spear Saga is still coming.  I promise.  But … on Sunday I watched part one of the Nova documentary “Becoming Human“.  Part one was entitled “First Steps” and it seems to tie very neatly into my own speculations from the Ancient Computing Revolution post.

The main question that “First Steps” attempts to answer is that of what evolutionary forces led the ancestors of modern humans to walk upright and then to become more intelligent and to create tools.  The documentary focusses on relatively recent hypotheses.  Namely, in the case of bipedalism, that it is simply more energy-efficient to walk on two feet.  The energy savings might not seem like a big deal, but this idea makes a lot of sense to me because of my own personal experience.  I have a permanent foot injury that prevents me from putting a lot of pressure on my right heel.  Although many people don’t notice it until they’ve been around me for a while, I always walk with at least a slight limp.  When walking at a comfortable pace, this doesn’t make much difference.  But when I start running or jumping rope it becomes obvious that I’m not doing it the way it’s normally done.  I’m quite fortunate that I’ve been able to adapt and that I can still walk, run, and jump when I need to, but I don’t do it as efficiently as I would without the injury.  When I’m walking and tired I know I really miss heel strike and I imagine it would matter even more if I were struggling to get enough food.

“First Steps” cites a change in our ancestors’ natural habitat as the driving factor for that change: they needed to walk farther each day to stay alive.  The changing environment is also cited as the catalyst for our increased brain size and intelligence.  Geological evidence shows that at the time when homo habilis (the first tool-making ancestor of modern humans) emerged, the climate was frequently and drastically shifting.  Ordinarily, when the environment changes, natural selection would produce creatures whose physical traits and hardwired behaviors were well suited to the new environment.  But that takes many generations to occur.  If the climate is changing dramatically every few generations, then biological evolution can’t keep up.  What it can do is allow a new kind of evolution to emerge – one that can adapt much faster.  To put it in the terms of my earlier post, they needed software which can be upgraded faster than hardware.

I look forward to watching the next part of this trilogy.  Part one was very informative.

Thank you for reading.

LINK: Part 2

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