I was in town the other day and walking leisurely in the streets of Nairobi. With the current traffic problems within the cities, it is pointless to drive to the centre of the city unless it is absolutely necessary, and the reason overrides the consequences. Without the worry of where to park and whether the car is safe, it feels much more relaxing walking amongst the people and window shopping.
Right ahead of me was this lady who was walking in the same direction as I was. Looking at her, she was very well endowed in the lines of size and shape. With what has become popularly known as the American height – as though that is where height was discovered – and a well-rounded full blossom, she cut out a figure that could be politely referred to as large. In this part of the world, big bodies mean well fed, good health and a caring husband – if the big body belongs to a woman. If the body belongs to a man, then the man is considered to be rich, and must have married a very good cook.
I followed this lady for quite some time, making sure I stayed well behind her so as not lose her in the crowd, but then avoided appearing as though I am stalking her. Suddenly she had become a target of my curious mind. Although compliments were duly observable, my mind was on a completely different journey. My line of thoughts was: how much have we changed as hominids from the times of the australopithecines to the present times of homo sapiens? What traits, physical or otherwise, do we see as evidence of evolution?
Those are the questions I was asking myself, as a believer on evolutionary science. To the creationists, I know the question would not suffice since if God created man, then man should remain the same over eternity, unless God goes back to the drawing table and carves out another creature to replace man. Science deals with provable evidence. If I believe in evolutionary science, then every opportunity to prove there is a continuous process of evolution taking place right before our own eyes must be embraced.
I was looking at this lady walking. Albeit because of her massive weight, she still had a springy gait. We humans, we believe, have evolved from the normal primates and taken a line of our own. Our closest relatives – the chimps – are still walking on all fours like we used to. But we have become bipedal. Walking on two legs require a great deal of stabilisation. Try making a stool with only two legs and make it stand on its own. It will not. Therefore, to be able to stand upright, walk or run on two supportive structures, it requires adoptive changes within human anatomy.
Members of the genus “homo” have substantial muscles that form at the rear end. The muscles are called gluteus maximus, or simply put, butt muscles or buttocks. These muscles are divided into two equal parts and placed identically under each hip joint to give support and equilibrium to the whole structure. Those butt muscles have numerous large attachments from the hip to the base of the spine, to hold them in place for the sake of balance. If you have seen a chimp in trousers in a circus, you have seen how baggy they look. They are gluteally (butt) challenged. Large butt muscles are not only better looking in pants, they also make for efficient energy transfer during walking by stabilising each hip.
The lady in front of me had stopped. I slowed down and allowed others to pass by. The lady bent down to tie her shoelaces. The butt muscles, hitherto lumped on each side like inflated balloons, spread out forming a perfect natural curve on each side of her hips. She was not struggling for balance or holding anything for support. Nature was revealing exactly what has had to change in order to keep the homo sapiens on bipedal.
In contrast with the trunk, the shoulder of the chimp is well stabilised, tied to the spine and the head by very strong muscles. Moving on all fours involve moving shoulders. Through evolution, we have lost that but with good reasons. As we walk on twos, the shoulder hardly moves and therefore we use less effort above the hips to stabilise the trunk. Those are physical evidence of evolution taking place in species “homo”.