Thursday, 27 November 2008

Evolution of the human brain

Once upon a time, some thousands of generations ago, man reached a threshold and crossed it. Somewhere in the evolution of the brain, something unprecedented happened – effecting life on Earth. The human brain changed and was suddenly able to compute, manage and store information like never before. Man had become clever.

Let's take a look at why and how this happened...

The first brains

Animal life first originated in the sea, where there was an abundance of Omega 3 fatty acids. As time went on, flowering seed plants appeared and with them a brand new fatty acid family was introduced. The seed oils of these plants contained Omega 6 fatty acids. Now for the first time, the Omega 3 and Omega 6 fatty acids families existed on earth together. This apparently opened the door for an entire new set of species to arrive that would develop a bigger brain. You!

How did the new species develop bigger brains?

Well unlike the fish and reptiles of the time, the new species, called mammals did not lay eggs. Mammals kept their offspring inside their bodies, surrounded by a sac called a placenta. The placenta is a powerhouse of nutrients and energy and 70% of the calories are devoted to brain growth. No wonder they grew bigger brains.

The big brain change

We Humans are thought to have lived on earth for millions of years, however the big brain change happened only in the last 200,000 years or so. What could have caused the change in human brains? And why did some human brains change and others stay the same? Could it have been what they ate?

The puzzle of the big brain change involved the discovery of early human populations that demonstrated greater intelligence. Another break through was in the discovery that DHA (docosahexaenoic acid) was a huge contributor to brain growth. Now DHA was found in seafood and it was shown that people who lived near water sources and ate seafood experienced the big brain change. In contrast, the populations inland (e.g. Australopithecines) did not have access to omega 3 and got stuck at a brain capacity that was not much bigger than a chimp for three million years. It's not funny!

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