How to understand evolution by natural selection

To tell the truth, the title should have been, “How I understand…” But, the reader count for the post would have struggled to go beyond one, not to mention double digits. Hence, the ruse to begin this post. I promise, however, the rest is true to the best of my knowledge.

In his book How the mind works, (Penguin Books, ISBN 0 140 24491 3) Steven Pinker says that to understand how the mind works, we may start with what we think as simple tasks, like bipedal motion. He quotes Confucius, “A common man marvels at uncommon things; a wise man marvels at the common place.” There is nothing as common as walking, getting there from here. Is there?

Pinker says that the complexities of eyes, ears and all the other inscrutable organs will amaze you about the workings of our brain, but bipedal motion – walking erect – will inform you the variety of tasks that need to be accomplished and the sensors that are in operation more clearly than the others. Pinker quotes an engineer: “[T]he upright two-footed locomotion of the human being seems almost a recipe for disaster in itself, and demands a remarkable control [brain being the control center] to make it practicable.”

Now, I want to refer to Don’t you have time to think, a compilation of letters by Richard P Feynman, edited by Michelle Feynman (Penguin Books, ISBN 978 0 141 02113 3). In a letter to his wife dated May 17, 1945, almost precisely a month before she died of Tuberculosis, Feynman writes his experience babysitting his boss’s son, a year and few months old: “Didn’t cry the whole time, although he fell on his bottom [my emphasis] several times while walking around the house.”

“[F]ell on his bottom …” that is where the clue to understanding evolution by natural selection is. Now, going back to Pinker’s book, “When we walk we repeatedly tip over and break our fall in the nick of time.”

I have no children to call mine and that makes me the best layman observer of all children. I have never seen a toddler taking stuttering steps that does not create anxiety in my mind on the child falling flat on its face. But, guess what, it is almost always falling on its bottom, just like Feynman noted. Now, this could only mean that the toddler had cut more slack in the “nick of time”. It overbalanced and fell backwards, on its fleshy bottom, saving its face. Babies have cute faces and cushy bottoms, you would agree. So, what would you like saved? The face. What would save you? The bottom. That is survival. That is natural selection. That is evolution.

Human beings came on the scene very late, say, 6 million years ago, when we separated from chimps. Bipedal locomotion is one of the characteristics of the species Homo sapiens shared with, except as an exception to normal modes of locomotion of some of our close cousins, none. It had taken that long for nature to figure out how to move across uneven terrains efficiently, using only two limbs.

It is telling that one of the ways people are trying to mimic human locomotion, though using spheres, is for the top portion of the contraption to lean forward to bring the ground level ball to move forward to achieve balance and move! We are trying to ape nature to create an artificial bipedal locomotion!    

This is how I understand evolution by natural selection.

Raghuram Ekambaram