Could you please read my essay and give me some feedback? Thank you very much!
The prompt is:
During the Pleistocene, there were actually several hominid species living in Africa and other areas. What are these species and where have their fossil remains been found? Speculate as to why only one of these survives to the present.
Thank you in advance
The earliest evidence of the presence of hominoids in Africa dates as far back as about twenty two million years ago. During about eighteen million years they radiated from Africa to Europe and Asia. Later, the first individuals of the genus Homo, the hominids, appeared in the Pliocene epoch which ranges from five million years ago to one million eight hundred thousand years ago. They were mainly composed of Australopithecines, in central and eastern Africa. The Pleistocene period, which ranges from one million eight hundred thousand years ago to ten thousand years ago, and which is divided into three parts, is of particular significance for the anthropologists because of numerous modifications in terms of biological evolution and geographical repartition. Surprisingly enough, only one species has succeeded in escaping the extinction all around the world: Homo sapiens sapiens, namely us. So astonishing a conclusion leads to closely examine what Hominid species have been during the Pleistocene, where they have lived and consider why there has only been one surviving species.
First, the Pleistocene, which ranges from one million eight hundred thousand years ago to ten thousand years ago, is emphasized by the Homo erectus species. The Homo erectus individuals are of particular importance since they have been the first hominids who have left Africa. Homo erectus remains have been found on three continents: Asia, Europe, and Africa. In Java, an island in Southeast Asia, and at Zhoukoudian, in China, various remains of Homo erectus have been discovered. As regards Europe, three crania in addition to partial mandibles have been revealed among the oldest Homo erectus remains on earth. However, those individuals were so primitive Homo erectus that they could have been classified as Homo ergaster. However, remnants of Homo erectus have permitted to testify the existence of Hominids in Europe, especially at the site of Dmanisi in the Republic of Georgia. Moreover, those Homo erectus remains bear witness to what seems to be the earliest African hominids emigrants in Europe. Other European sites epitomize the early hominids' evolutionary history diversity thanks to remains in Spain and Italy that present similitude with the Asian Homo erectus. African early hominids remnants illustrate the rich diversity of the early Homo in this region of the world and evolutions that have happened during the Pleistocene. Two Kenyan sites, in the East and West Turkana, have provided the scientists with precious indications about the presence of Homo ergaster individuals, who lived about one million six thousand years ago, and who have exhibited more or less marked differences with the Asian Homo erectus. Conversely, about six thousand years later, Homo erectus has lived in the area of Bouri in Ethiopia and has had relatively analogous morphology in comparison with the Asian Homo erectus. Remains have also been found in North African, in Morocco and Algeria, but due to the insufficiency of those early materials, which have been only composed of mandibles and partial parietal bones, the genus has been defined as Homo, the species is difficult to classify with certitude. Consequently, it appears that Homo erectus species has emerged in Africa and subsequently migrated to Europe and Asia.
Second, the middle Pleistocene, which ranges from four hundred thousand years ago to one hundred and twenty five thousand years ago, characterizes the epoch of the Archaic Homo sapiens. Several transitional hominid species, which have undergone a mosaic evolution, have materialized a speciation with the emergence of two species in the genus Homo in parallel with the development of Homo erectus. On the one hand, the anthropologists have demonstrated the presence of the Homo heidelbergensis species in Africa from six hundred thousand years ago to about one hundred and thirty thousand years ago thanks to archaeological remains found in Kenya and Ethiopia. Moreover, they have been able to notice the existence of Homo heidelbergensis individuals in Europe from four hundred thousand years ago to three hundred thousand years ago due to the discovery of numerous cranial fragments in England, France, Germany and Spain. Finally, other Homo heidelbergensis remains have also been found in China and have revealed the existence of that species in this area about two hundred thousand years ago. On the other hand, another species in the genus Homo have surfaced in Europe and Asia and is associated with the anatomically modern Homo sapiens: Homo sapiens neanderthalensis. The scientists have revealed that those individuals lived in the Israel and Iraq from about one hundred twenty five thousand years ago to sixty thousand years ago, and in Croatia and France from fifty thousand years ago to twenty eight thousand years ago. The significance of all those individuals lies in their anatomical and cultural traits that have revealed they have far more developed in the human direction than Homo erectus, which is the reason why the anthropologists have considered them as pre-modern humans.
Third, the upper Pleistocene, which ranges from one hundred and twenty five thousand years ago to ten thousand years ago, is the cradle of the anatomically modern Homo sapiens, which has been available in three subspecies: neanderthalensis, sapiens and florensis. Homo sapiens sapiens has been remarkable because of its emergence in Africa, about one hundred and sixty thousand years ago in Ethiopia, then its subsequent expansion in Africa and, above all, on the five continents. Those Homo sapiens sapiens individuals have interbred with local people, who originated from the migrations of Homo erectus during the lower Pleistocene, and therefore evolved in diverse directions. Consequently, the anthropologists have found remains of Homo sapiens sapiens that have presented considerable variations between different geographical locations. However, one anthropologists' enigma has stemmed from the discovery of remains of a dwarfed species in Indonesia that is so divergent from the average anatomically modern Homo sapiens that the scientists have supposed those individuals could be a kind of cul-de-sac in the evolutionary history of the Humans species.
Finally, when one observes the hominoids' evolution in terms of chronological and geographical progressions, the first reflection that surfaces is that it is quite surprising that only one species has succeeded in surviving up to now. In my opinion, prior Homo species have not achieved to avoid the extinction because they have not been able to adapt to the ecosystems of their respective habitats. Consequently, due to the selective pressures exercised by ecological conditions, such as the severe climatic changes during the Pleistocene in Eurasia, and the competition for resources, one could deem that many species have been able to adapt. Consequently, that individuals' reproductive success has dwindled, and therefore they have seriously threatened the entire survival of their species. On the other hand, although I reckon the arguments that buttress the opinion that the Homo sapiens sapiens species is the only one survivor of the human epopee, I am not convinced because of certain elements that could moderate that view and open new vista. The principal aspect that I consider as dramatically astonishing is the fact that recent ameliorations in the genetic engineering field have revealed the presence of Homo sapiens neanderthalensis' traces in the contemporary humans' genetic code. That aspect has been unveiled thanks to the discovery of geneticists who have demonstrated that the mitochondrial DNA is transmitted by the mother to her offspring without any alteration during the meiosis, which is the process of sex cell division during the interbreeding. Moreover, archaeology has also provided anatomical evidence of interbreeding between sapiens and neanderthalensis individuals. Consequently, one could conjecture that the Homo sapiens sapiens and Homo sapiens neanderthalensis have amalgamated in the area where the two species were present, namely Near East and Europe, but that Homo sapiens could have had more dominant advantageous traits that have leaded to produce more and more sapiens-like individuals in the descent lines with the passing years. Due to the fact that sapiens and neanderthalensis classifications are only theoretical divisions of the same species because all those individuals were able to interbreed and produce viable offspring, one could argue that Homo sapiens neanderthalensis have also, to some extent, succeeded in surviving. This perspective may seem controversial but the tremendous progress in genetics could surprise us even more in the future.