Human evolution process is an important aspect of both the history of modern mankind and the development of our way of life as we know it. The process focuses on the developmental and evolutionary process of the primates and specifically the genus Homo. It also looks at the emergence of the Homo sapiens who are a divergent species from the hominids. The hominids are the initial form of human and are also referred to as the 'great apes.' Various genetic studies revealed that the primates (apes and the chimpanzees) diverged from other mammals in the Late Cretaceous period nearly 90 million years ago. The earliest genus Homo recorded was Homo habilis which evolved nearly 3 million years ago. They were followed by the Homo erectus who came to be due after rapid encephalization millions of years later. Unlike their predecessor, the Homo erectus had a larger cranial capacity of almost 950 cubic centimeters. Later on the Homo ergaster came into existence, which originated from Africa and were the first to use fire and other tools. In theory it was speculated that the modern African man originated for the Homo rhodesiensis who migrates to the other parts of the world. History states that in the Middle Paleolithic period the homo rhodesiensis evolved into Homo neanderthalensis and the Homo sapiens who are the true anatomy of the modern man.
The Neanderthal is a species of the humans that existed almost 200,000-300,000 years ago in west Europe, Eurasia and parts of Asia. Although some archeologist have disagreed there close connection to the modern human beings, the fossils found differ. Paleontologists have classified the Neanderthals as a subspecies of the Homo sapiens and they are also known as Homo neanderthalensis. According to the various test conducted on the fossils found, it was discovered that the Neanderthal's DNA match to that of the modern was almost 96%. It was discovered that the Neanderthal's anatomy was identically the same as that of the human beings, as they had the same number of bones with the same functionality. Though there are various differences, the differences have been found to be very trivial in nature. However one may wonder why the morphological study greatly distinguishes the Neanderthal from the modern human being. Characteristically the Neanderthals lived in exceedingly cold climatic regions; this made them genetically different so as to adopt to the harsh climates thus the difference in morphology (Stringer and Makie, 1996).
Allen and Burgmann came up with two distinct rules to explain the relationship between the shape and size of the Neanderthals' limps and also chest anatomy. According to Burgmann's rule the Neanderthals' had a huge chest which is an adoptive trait to help them survive in the cold climate. He explained that the larger the body the less the surface are per volume ratio hence the large trunks will help them retain more heat in the cold climatic conditions. Allen's rule on the Neanderthals' had shorter limps which helped them retain more heat produced by their bodies. This today can be observed in the short tails and beaks of animals living in the cold climate, and also the Eskimos who are always short and large (Holliday, 1997). Further research revealed that the Neanderthals' in the warmer region of the Asia had longer limbs and had slightly smaller trunk anatomy. In addition based on the various studies conducted it was established that the Neanderthals' life style may have affected their skeletal structure as they performed strenuous activities. This is evident in the massive bone breakage of the fossils collected. Studies undertaken recently suggest that the Neanderthals' may have had larger longevity based on their dental study (Cuozzo, 1998). According to Deacon (1994), the Neanderthals' brain capacity surpasses or is equivalent to that of the modern human beings, with a brain capacity ranging between 1300-1800ml. Even though a direct correlation between the intelligence and brain size of the Neanderthals' hence one cannot argue out the presence of any evolutionary expansion in their cranial capacity.
One might ask himself, did the Neanderthals communicate, and if they did was it verbal or did they use signs and symbols to convey any message? Well initially most evolutionist claimed that the Neanderthals had no sense of speech as the modern man. This was because they had a horizontal non-flexing muscle at the base of the skull and also the larynx in the throat was positioned higher than that of the chimpanzees and the modern man (Trinkaus, 1992). However this study was disproved by Jean-Louis Heim in 1989 who was also a paleoanthropologist. According to Jean-Louis the flexation of the Neanderthal which was at the base of the cranium was quite similar to that of the human beings. Thus the Neanderthals were capable of communicating as they had a sense of speech. History further explained that in 1983, the first complete Neanderthal skeleton was discovered in Levant. The skeleton had hyoid bone, which was the first bone of its kind ever discovered. It was discovered that the bone was positioned at the throat, and this was directly identical to the structure of the modern human beings vocal bands (Arensburg, 1989).
Over the years, archeologists discovered that the Neanderthals had a way of life just like the modern man. The Neanderthals had tools, used fire, buried the dead, had musical instruments, practiced religious ceremonies and also used verbal language to communicate to each other. The Neanderthals were hunters who fed on sea creatures thus the need to have tools. This shows that the Neanderthals had a relatively complex thinking capacity than that of other animals. In the early 1980's some archeologist discovered remains of the Neanderthals which were deliberately buried. For instance at a site in Uzbekistan a boy's remains were discovered, and the grave was encircled with mountain goat horns, bones and other tools which were an indication that the Neanderthals conducted some sort of ritual. According to Trinkaus and Shipman (1992), the placement of the bodies found in the graves showed that the bodies were not dropped haphazardly. There indeed was some sort of order followed while putting one of their own to rest. Even though the concept of 'conducting ceremonies,' might have a different meaning and impact than it did during the ice age, it symbolized a sense of humanity.
The divergence of the Homo neanderthalensis and the Homo sapiens form the initial species marks an important point in history for the modern human beings. This phase is quite crucial as it marked the separation of the two lineages and the conception of humanity as we know it. The analysis and interpretation of the Middle Paleolithic record on the fossils collected is crucial to understanding the separation in terms of the paleontological and the paleogenetical features of the two. In order to understand the Neanderthals' better and their relationship to the existence of the modern man, a group of evolutionist, conducted a research study on the mitochondria sequence of the Neanderthal man. One of the major reasons that led to the studies was to investigate how close the two groups really were to each other. The second reason was to determine the exact date of the separation. Various authors agreed that even though there might be a significance difference in the mitochondria DNA of the Neanderthals and the modern human beings. However others have argued out that the lack of Neanderthal linked haplotypes in the modern man does not mean that there was no interbreeding between the Neanderthal and the modern man. The authors stated that there is a similarity in the cranial structure western and African Eurasian Middle Paleolithic hominids. These features are mostly related to the advanced level of encephalization which took place during the existence of the Homo erectus. The process had quite a number of consequences and they included comparatively higher cranial space, a wider fore and stouter posterior space, and probably a more arched basicranium. However, it is important to stress on the difference in the genetic coalescence, separation in the population, and also the phenotypic diversity of the two taxa denoted chronologically separate events. The mitochondria DNA from almost 15 Neanderthals were efficaciously sequenced in wholly. It provided approximations of the dates of divergence date between the Homo sapiens and Homo neanderthalensis mitochondria DNA pedigrees. The latest estimation of the pedigrees was placed at 660 ka plus or minus 140 ka. Calculations done based on the autosomal genome placed the joining time at 700 ka and the separation time of the population 370 ka. Evolutionist argued out that even though the Neanderthals contributed to the existence of the modern man, the significance difference in the mitochondria DNA shows no relation.
Nonetheless according to Lubenow (1998) the above interpretation was not technically reasonable. This is because the use of an arithmetical average of a large population of the modern human sample as a point of comparison with the mitochondria DNA of that of the Neanderthal man was not appropriate. Analysis revealed that the mitochondria DNA alteration among the modern human ranged between 1 and 24, and with a substitution difference of 8. While that of the Neanderthals ranged between 22 and 36, thus placing the Neanderthals at the peripheral of the range of that of the modern human. Quite a number of archeologists have proposed various dates of the population's separation and the progress of phenotypic distinction between the lineages, and ultimately the species' acknowledgement. An early deviation theory was majorly based on the analysis and dating of the plentiful gathering of the human remnants from SH. This collection signifies the most convincing piece of proof that brings forth the acknowledgment of the Neanderthals' morphological feature in the early Middle Paleolithic period in Europe. A high resolution study and other series of tests analysis obtained from the speleothem: these are structures formed in caves by mineral deposits in water, dated the fossils separation period to almost over 35 million years. This fact however raised a lot of issues since the estimated dates were closely estimated to the coalescence the paleogenetics provided.
Lately, new developments on the Neanderthals' genomics have prompted re-evaluation and analysis of the DNA sequence of both the Neanderthals and the modern man. Quite a number of archeologists believe that there is a possibility that the Neanderthals contributed to the existence of the modern man. They argued out that the previous test might have yielded different results because they were contaminated. For instance two group of archeologist: Noonan and his colleagues, and Green and his colleagues: carried out a test using the same specimen but ended-up getting different results. According to Noonan the estimated time of divergence obtained from the test was 700,000 years and the estimated split time was almost 350,000 years. Yet according to Green and his colleagues the estimated time of divergence was almost 510,000 years. The time difference between both teams is almost 190,000 years, which is too large a margin thus the results were not reliable. Recently it was discovered that the distribution of genetic variation of both the Neanderthals and the modern humans was construed so as to support the replacement and the multiregional evolution theories. The replacement theory stated that the Homo sapiens evolved in Africa but later on migrated to the other parts of the world and thus replacing the ancient human such as the Neanderthal man. Most authors believed that the recent analysis and interpretation of the human mitochondria DNA especially the Y chromosome might be evidence that supports the replacement theory. Fagundes (2007) used data from over fifty human genomic loci which were compared to different versions of the multiregional and the replacement theory. It was noted that the data had 78% posterior match. The conclusion to this finding is that the modern human beings came into existence almost 140,000 years ago in Africa and later on migrated around 51,000 year ago.
After an in-depth analysis of the various research and interpretation of various research conducted by quite a number archeologist, it is true to state that the interbreeding between the Neanderthals and the modern man if any is quite low. However one cannot dismiss this fact because there is the possibility that the low level of interbreeding might have resulted to the transfer various alleles. An allele is a gene that comes into existence due to the occurrence of a mutation and is usually found in the chromosome. Research states that valuable alleles can exist in a certain hybrid even if the hybrid is not fit and compared to the parent population. Nonetheless these alleles can be passed from generation to generation as long as the hybrids are fertile. After years and years of research there are claims that there is the possibility of adaptive introgression from the Neanderthals to the modern man populations at the microcephalin loci. The microcephalin loci are gene sequences that are expressed during the initial stages of brain development. Supporters of the multiregional archetypal have suggested that the adaptive introgression could have been the principal source of some of the beneficial alleles during the initial stages of the evolution of modern humans. Although the human and Neanderthal genome sequence does not support the adaptive introgression theory, one cannot ignore it completely, as there is the possibility of its existence even though it might be low (Hardy J, 2005).
If one was to concentrate entirely on the biological feature, mitochondria DNA sequence, date of existence and also the behavioral traits of the Neanderthals one might conclude that the Neanderthals' humanity could be compared to that of the animals. Nevertheless, after an analysis of Moula-Grey's theory and hypothesis one cannot ignore the fact that the Neanderthals and the modern man are more or less similar to one another. To begin with, both the Neanderthals and modern man practice cannibalism. According to Moula-Grey cannibalism can be for ritual purpose or for survival. Evidence obtained from the fossils dug shows that the Neanderthals fed on each other so as to survive. Neanderthals were hunter in nature. They lived in the artic regions which is quite cold thus prone scarcity of food. The Neanderthals would prey on the weaker ones and they would butcher them just like did with the animals. For instance, the archeological remains of two adults, two adolescents and two children were evidence that illustrated the cannibalistic nature of the Neanderthals. As par the analysis of the bones it was established that their craniums had been crashed and the brains eaten. Moula-Grey noticed that one of the child's tongues was cut. The limps had been skinned and the bones broken or cut off entire. Since the Neanderthals lived in small groups, it appears that either the victims where the weakest or they were caught off guard by the neighboring community. However, unlike the modern man who offer rituals, the Neanderthals cannibalism was purely for survival. This is because a comparison with the animals' fossils shows that the six where butchered the same way the animals were butchered. Modern man on the other hand, practiced rituals that involved them eating a fellow human being. For instance in Colorado, Alfred G. Parker was accused of eating member of his group. I believe that modern man and the Neanderthal are quite close since regardless of the reasons they seem to have a culture in which they believe in. Both populations have more similarities than the differences. Even though both existed in different environments and times, one (modern man) appears to be an improved version of the other (Neanderthal).