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Does Darwin's Theory of Evolution explain why the human brain is so big?
Darwin's theory specifies descent with modification through naturalselection. What that means essentially (and as an oversimplification) is that DNA - which we now know to be …the engine ofchange in species - is copied wrong, on occasion, leading to amodified gene. Sometimes those modifications have consequences forthe animal. In the case of human brain size, perhaps some earlyhominid had a gene coding for the additional split of neuronsduring it's prenatal life (all animals, even ants and beetles, havethe same basic brain chemistry. The main difference is that, duringdevelopment, higher animals' brains are told to keep producingneurons, thus increasing in size to accommodate. Our brains producethe most neurons per overall surface area). So this hominid, andit's offspring, and maybe some relatives all have slightly betterbrains than their contemporaries allowing them greater powers ofabstract thought, communication, and organization...MAYBE. Theysoon start out competing their neighbors for natural resourcesthereby increasing their numbers though better food, shelter, etc(again, this is all hypothetical and oversimplified). Soon theirnumbers are so great, they completely overwhelm the competingpopulations whose numbers crash. They are, unwittingly, movingtoward becoming a new species, over thousands of generations, withslightly bigger brains. With the better food (mostly protein) comesthe fuel to support the development of such large brains. The same is true for all modifications from giraffe necks to whalespouts. They developed overtime through a series of accidents thatworked in the animal's favor environmentally. (MORE)
