We are an advanced breed of monkey
on a minor planet
of a very average star.
Stephen Hawking
About 6 to 7
million years ago humans and chimpanzees diverged from an earlier primate
ancestor, though we still share about 97% of our DNA with our chimp cousins.
Somewhere
around 4 million years ago our pre-human ancestors became bipedal, and about 3.5
million years ago Australopithecus Afarensis became distinctly human.
There were
many evolutionary adaptions that developed and died out, but about 1.8 million
years ago Homo erectus became identifiable with present day humans.
It was Homo
erectus that left the cradle of Africa and spread through Asia and southern
Europe.
Evolutionary
adaptations produced Homo Heidelbergensis and then Neanderthal and finally
modern humans. It is estimated that
about 2.5% of the DNA of humans outside of Africa is Neanderthal.
Human
evolution is not only obvious from physical appearance and mobility, but also
in brain development.
Over the
course of human evolution three distinct brains emerged. The oldest and most primitive is the brain
stem and cerebellum (which turns out to be the main structure of the reptilian
brain) which controls autonomic body functions.
The next layer of our brain to develop was the hippocampus and
hypothalamus which records memories and experiences. The final layer is the cerebrum that allows
language and abstract thought.
The brain is
not static, but constantly rewires itself to adjust to new experiences and
demands. The human brain is even known
to repair itself (rewire itself) to bypass effected neurons in stroke victims.
Time on an
evolutionary scale is vast, and if we survive there is no reason to believe
that ‘we’ are the final product of human evolution.
The future
of humans no longer depend on survival skills, size or wit. We live in a society that services our
needs. We are less active and less imaginative. We depend more and more on technology.
So what
evolutionary changes in the human animal might we expect as people move from a
world of personal interaction, required physical activity and survival demands
to a virtual reality world of 24/7 TV, computers and cell phones?
Just
wondering
the Ol’Buzzard
That cartoon movie Wall-E seems closer to coming true more every day. It scares me.
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