Monday, September 14, 2015
THIS AIN’T ANCESTRY.COM
We are an advanced breed of monkey
on a minor planet
of a very average star.
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?