PROCESSES AND MECHANISMS OF HUMAN EVOLUTION

 

Although general evolution (speciation) has two main parameters (dynamics)—variation and natural selection pressure—human evolution has three main parameters (dynamics).

 

These are: in addition to the shared parameters of variation and natural selection pressure, a skeletal transformation triggered (initiated) by bipedalism, which has lasted for seven million years and continues today. This third parameter is what makes humans different from other living beings (i.e., an intelligent being). This parameter has continued for seven million years in every hominin species, independent of variation and natural selection pressure. It continues in all hominins regardless of whether a population migrates toward the poles or the equator. It is this ongoing skeletal transformation that will lead this organism (the hominin) to become an intelligent being.

 

While populations dispersed across the world undergo geographic adaptation through natural selection pressure separately, this skeletal transformation initiated by bipedalism continues simultaneously in all hominin groups.

 

So how does this skeletal transformation lead to humans becoming intelligent beings?

 

If we define general evolution as qualitative transformations resulting from the accumulation of quantitative changes over long periods under natural selection pressure, then human evolution can be explained by adding the seven-million-year-long skeletal transformation to this process.

 

The skeletal transformation begins with the big toe and continues with the elongation of the leg bones, the pelvis taking on a bowl-like shape, the torso becoming upright, the rib cage becoming cylindrical, the skull taking on an arch-like (Roman arch) shape and enlarging, and the jaw becoming smaller, resulting in the formation of what is called the “chin” at the tip of the lower jaw. The upright posture of the body is necessitated by the requirement that the axis of body weight remains within the area of the soles of the feet. If you lean forward from your waist, beyond a certain angle you will fall, because your center of mass moves out of the area of your feet. This is a requirement of physical laws and the biomechanics of hominins. If a living being does not have an optimal locomotion (movement) mechanism, it cannot sustain its species.

 

When the upright posture reaches a certain level of quantitative accumulation, a qualitative transformation occurs, and the embryo in the womb flips and turns its head toward the mother’s diaphragm. I call this the “cognitive flip.” It is this cognitive flip that has led to the rounding and enlargement of the human skull.

 

Since I have proposed experiments related to this subject and presented them at universities around the world, I do not elaborate on this topic here.

 

When skull enlargement begins and reaches a certain volume (600–700 cc), this organism gains sufficient brain size and mental capacity, enabling it to develop language and control fire. Without a certain brain size and mental capacity, no living being can develop language or control fire. Since there was a sudden increase in brain size in Homo habilis, which lived two million years ago, I propose that this “cognitive flip” occurred around two million years ago.

 

In recent years, genetic material extracted from Neanderthal, Denisovan, and Floresiensis fossils has shown that we exchanged genes with these three groups (which I argue are not separate species). Later, proteins extracted from fossils of Australopithecus africanus, Homo rudolfensis, Homo habilis, and Homo erectus were studied, and it was concluded that, like the previously mentioned three hominins, they also exchanged genes with one another.

 

From this perspective, if we consider a model in which each preceding hominin is a thesis, the next is an antithesis, and the following one is a synthesis—from Sahelanthropus tchadensis, which stood upright seven million years ago, to Homo sapiens—we can think of all these hominins as transcending one another by incorporating each other, culminating in Homo sapiens. In other words, we did not exterminate Neanderthals; we surpassed them by incorporating them—we received DNA from them (about 4% of our DNA).

 

In summary, hominins are not entirely separate species; rather, through gene exchange (interbreeding) and by incorporating one another, they have continued to the present over approximately 280,000 generations.