One of the significant evolution of man that enabled him to conquer a wider area on earth compared to other primates is the acquisition of the upright posture which freed its hands. This trait enabled the Homo sapiens to make tools, make better shelters, and be better gatherers compared to their ancestors, the Homo erectus, and other earlier hominids. They were also able to defend themselves better. Indeed, the emergence of H. sapiens approximately 240,000 years ago saw the disappearance of these earlier hominids. One of the distinguishing traits between the early hominids and the modern man, apart from the intelligence associated with H. sapiens, is hairiness. The gene responsible for this trait is the hair keratin gene KRTHAP1. Over time, this gene has been lost or modified into a lesser expressive type in the human lineage. Its loss or modification can be attributed to evolution supported by natural selection. That is, the undesirable gene was gradually selected against by forces of nature. As man’s intelligence grew due to an increased brain capacity and the freeing of his hands he became more creative and made special shelters that were warmer and clothes that could be worn to keep the body warm. Thus, those individuals who were considered weak; the hairy individuals, were naturally selected against and hence their genes were not passed on to the next generation.
The theory of evolution is heavily hinged on the natural selection of genes that are considered unsuitable or suitable. The loss of this gene responsible for hairiness can be traced to approximately 240,000 years ago when the intelligent hominid emerged. As this gene was being selected against and the individual carrying them died without passing them on to the next generation, their allelic frequencies in the population changed permanently. However, individuals who lacked this gene, the H. sapiens and better suited, gradually changed the allelic frequencies of this gene as their lack of hairiness was inherited by their offspring. Even though many people in the world today are considered to be hairy, they possess a variant of the hair keratin gene KRTHAP1. The genetic variation can mainly be attributed to genetic mutation, an independent assortment of genes, and the exchange of genetic materials during the crossing over of genes as during meiosis. These are the main sources of raw materials for evolution. The world today is also witnessing a phenomenon of evolution where many hairy individuals have evolved to inhabit colder areas of the earth and vice versa. These individuals are naturally selected to inhabit such regions since their genes are more suited to such temperatures.
Evolution is a slow process that takes many years and thus may be difficult to notice. However, genetic analysis of the various gene and gene products of the hominid fossils discovered by the archeologists reveals that these early hominids, our ancestors who lived millions of years ago, had hairs. Moreover, the studies reveal that over time the gene coding for hairiness phenotype, gradually changed under the influence of natural forces to produce the relatively hairless men we have today. It is undeniable that we originated from these early hominids. And since they had hairy bodies and we don’t, this calls for one explanation that these hominids evolved over time. The evolution occurred in their genes that code for hairiness and through natural selection, we inherited the genes. However, due to the same forces of evolution, variations occurred.