Question: what makes the brain the shape, size and colour that iy is???

Jen Todd Jones answered on 12 Mar 2013:

Hi Jenny!

The reason our brain the way it is is because of the evolution of human beings. A long time ago we were just like monkeys and we walked on all fours, on our feet and hands. Then when we started to evolve into human being we started walking on just our feet so that we could use our hands for more important things like eating and hunting for better food. When we did this our pelvis (the bone that our legs are attached to) could only grow to a certain size or we couldn’t walk on just our legs – this meant that the womb where babies develop and the birth canal through which they are born can only be a certain size. Because of this babies are born so small and defenceless, with the brain still not fully developed – human young cannot develop fully inside the womb or they’d be too big to be born! Because of this the skull can only be a certain size, the brain needed to fit inside it and would have done so well just as a big smooth round object. But the surface of the brain, also called the cortex, is important for thinking, so as we evolved and developed more thinking we needed more brain surface – but how could we fit it in? Instead of the brain being bigger it folded in on itself so that there was more surface packed into a small space.

This is the reason for the size, the shape is decided because the shape of the skull is the most efficient way of holding a brain inside a large bone-structure without leaving any parts vulnerable to damage.

The brain is pink in colour inside the skull because it has red oxygenated blood from the heart pumping through it constantly. When we die the brain drains of blood and becomes grey or white!