Riddles of evolution
scientifically, there is virtually no perfection in the biology of living organisms and what is present is a recurrent experiment of multiple and changing designs, some of which fail, dissolve and rapidly become extinct, while others succeed and survive for long periods, but ultimately all living beings become extinct for purely natural reasons such as the change in the environment or failure to compete with new species of organisms or the like. during a seminar a ‘lecturer’ said the geological evidence suggests that about 7 million years ago, the climate change in the world led to a major decline in forests in east africa and as a result, large swathes of savannah plants grew, therefore, our ancestors had the opportunity to leave and move to forests and adapt to the nature. here we come across the logic of walking on two legs, which is a rare phenomenon in mammals, where our primate ancestors were able to climb trees and walk on their four limbs. the second factor was the growth of the brain, the evolution of its size and role. what are the consequences of walking on legs and the big size of the brain? certainly walking on two legs has had a tremendous impact on the development and evolution because the modern man was able to free his arms from the function of walking on four limbs and to make room for the manufacture of tools and make use of the arm to throw with a degree of strength and accuracy unlike any other creature, in addition to other benefits. but because the human skeleton is descended from origins that were walking on the four limbs, some of the negative outcomes of spinal cord, pelvis, hip and knee changes occurred to members and were able to walk on two legs instead of four. walking on legs also played a major role in determining the pelvis, which is also the birth canal of a woman. for a woman to walk and run in balance, her birth canal has to be narrow, while this limitation does not apply to objects that walk on its four limbs. here we come to the second characteristic, the size of the brain. the human brain began to grow dramatically about 3 million years ago. of course, the size of the brain determines the size of the head and the increase in size of the head in the newborn needs a wider birth canal, but we noticed that the birth canal has been reduced by walking on two legs. here we face the random selection of natural changes that causes changes in the human body and result in opposite effects, one of them is radically illogical or even completely insane. it is clear here that there is a struggle for the forces of nature where some of the qualities converge more successfully than others regardless of whether it is contrary to other qualities. i mentioned some of the supposed causes that led to walking on two legs, but what caused the human brain to grow to the shape we see today? the views vary, but there is a very common and convincing assumption that the main catalyst for the massive growth of the human brain is the increase in the number of people in the savannah community and the complexity of the relations among these groups. there are also other important factors such as man depends on cumulative culture.
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