Of Brains and Brawn: Human Evolution

Carl Zimmer writing in the 8 July 2011 DISCOVER science magazine notes that in 1758 Carolus Linnaeus in creating his taxonomy labeled humans, “Homo sapiens” which is Latin for “wise man.”  Zimmer says one might question how wise humans are but far less questionable would have been to call us Homo megalencephalus – “man with a giant brain” since compared to the body size of other animals, our brains are huge.   On the other hand, humans have far less guts/intestines than one would expect when compared to the weights of other primates.  Studies also indicate that the human and genetic codes between chimps and humans differ in that the human genetic code led to the development of “molecular pumps” that funneled sugar to our brains, whereas in chimps the sugar is more funneled to muscle.  So even if you are not sure about certain people you meet, studies would say humans tend to have more brain while chimps more brawn.

According to Zimmer an amazing 25% of the calories we eat each day are needed to fuel the brain’s functioning.  So by thinking more could we lose weight?  He doesn’t say, and so far it isn’t working for me, but I’ll keep thinking a lot about dieting and see if it helps burn calories.

The size of the human brain and the amount of calories it consumes may also be a reason not to compare humans to rats or mice in certain scientific studies.  Such studies show that these animals when kept on a diet that includes periods of too few calories tend to live longer.  It is not known whether a similar idea applies to humans, but it could be that such a diet would end up starving the human brain and not prolonging human life.

Evolutionary science theorizes that it was humans changed from eating “lower-energy diets of barks and leaves to higher-energy cuisine of seeds, tubers and meat” which fueled the growth of the brain.  The brain demands a lot of energy to grow, and in animals more reliant on their muscle than their brains to survive, there is little chance for the energy to be funneled to the brain.  This may explain why though the large brain has helped Homo sapiens adapt so well to this planet, the large brain has remained a rarity in the animal world.  The flight or fight pattern of survival may draw too much energy to the muscles to allow the brain to grow.

Now, of course, there is the issue if we have all this brain, can we use it to further reduce the need for fight or flight survival and help all humans to further develop their potential?

We do not have to compete in order to survive on planet earth.  We can cooperate with one another to solve problems and to provide for the needs of our fellow humans.