The term mosaic evolution is used to describe the different features of an organism evolve at different rates. The efficient bipedal movement is a peculiarity that appeared very early and perhaps is the single most significant development in the emergence of man. Since this information is available from New Haven Teachers Institute, Yale, the information is accurate and reliable.
Article-3. Skybreak, Ardea. Part 6D: The Two Biggest Leaps in Hominid Evolution: The Science of Evolution, the Evolution of Human Beings. Revolutionary Worker #1182, January 12, 2003. Available at http://rwor.org/a/v24/1181-1190/1182/evol6d.htm
The process of evolution that links the modern human beings to the ancient ape ancestors revealed a number of key stages and milestones. The development of bipedalism in the line of apes is considered to the most important key stage in the evolutionary process. Secondly, the significant evolutionary modification apparently related to an overall 'slowing down' of hominid developmental rates that took place a few million years after the first growth of bipedalism and that formed the human infants to be born in an undeveloped and crude state but allowing for a tremendous increase in brain size and a much longer period of post birth brain development. This in turn enabled the unprecedented inquisitiveness that is attached to the characteristics of the human species.
The starting of development of bipedalism considered to be the first of major evolutionary changes resulted in variation of the basic form of locomotion of hominids and also permitted the hominids to expand their range into a greater variety of habitats and environments. Bipedalism is viewed as free hands for devoting to other purposes than the locomotion and extended an anatomical basis for such relatively simple things as routine carrying of food or other objects over longer distances and the simple use of unmodified natural materials as tools. A few million more years ago bipedal hominid species started to hit the stones together to produce sharp flakes and thus make simple stone tools. It is pertinent to note that many evolutionary and developmental biologists believe that many significant changes in the evolutionary process has resulted in consequence to the relatively simple change in the rate of improvement of physical structures in an ancestor population. The most important of these changes was the fact that infants were now born in a very immature and undeveloped state necessitating prolonged parental attention and vulnerable and dependent young.
The article further reveals that when modern apes and human beings are compared the distinctive features are apparent of the apes that are more typical of human beings. Most of these features are preserved in fossils. When it is possible to distinguish between the features those are more ape like and the features those are more like human beings, it is possible to analyze the fossil hominids of different periods during the past few million years and to find out an indication of the period of first evolutionary modifications that contributed towards becoming human. A plethora of information about the sequence of changes in the various hominid lines has come to picture in just the last few decades and particularly in just the past few years. A comparison of the characteristics of many different species of bipedal hominids reveals that the ones that are normally thought of as the early bipedal hominids that existed since the first development of bipedalism up to 2.5 million years ago still were having plenty of ape-like characteristics, irrespective of the fact that they walked upright. They were not all similar but on the whole they tend to be very short with shorter legs and longer arms, much like the apes that dangle through the trees. Therefore, it is true that the early hominids were also mostly ape like and therefore could not be called as some sort of little humans.
However, alternatively, they cannot be called as just apes and they were after all bipedal. It is quite essential to mention that distinction between the first members of our own Homo sapiens species and modern day human beings is mostly a difference in culture and none of this required any further substantial evolutionary changes in the fundamental biology of our bodies. Everything that we perform today is on the basis of the same capacity for learning and for infusing vast potentialities of accumulating knowledge across the generations through non-genetic cultural means that has been the evolutionary hallmark of our hominid species from the initiation. This is what makes us basically human and differentiate us from all the other species. To sum up it can be said that the specific methods of the evolution of the hominid line happened to unfold were not bound to take place. A differentiated group of evolutionary process could have evolved rather and the path of evolution could have taken any number of different twists and turns and never produced human beings at all. Since this is an article which appeared in a journal which has been referenced thoroughly the information is accurate and reliable.
Article-4. Carrier, David R. The Energetic Paradox of Human Running and Hominid Evolution. Current Anthropology. 1984 Volume: 25; No: 4; pp: 483-495. Available at http://www.publicanthropology.org/Archive/Ca1984.htm
Carrier in his article of hominid evolution advocates that irrespective of the high costs of energy in the hominid process, they evolved a specialized economy of energy use through physiological adaptations that helped them overcome this disadvantage. These editions drove them into a superior position in the predatory and evolutionary process. He backed his proposal with illustrations of hunters in varied cultures that engage in persistence hunting, a technique in which hunters make their prey run down until it dies from exhaustion. Taking the ideas and data from past studies of mammalian locomotion and energy expenditures, Carrier is could successfully measure the merits and demerits involved in various modes of locomotion and physiology ranging from rabbits to humans. He utilizes graphs and diagrams to depict his conclusions. The article is split into four prime divisions.
The most significant qualities of the hominid physiology assisted in surpassing the disadvantages of higher energy expenditures while running. The qualities are the dissipation of metabolic heat, the energy cost of transport and the storage and utilization of energy. The fourth section elaborates as to the methods of securing assistance by the endurance process for hominids and pave a new path for their evolution. Carrier finds out the specific thermoregulatory system of hominids and their capacity to vary the pattern of breathing while running, their capacity to adjust diet to enhance the physical efficiency and their complex glandular structure as assets that permitted them to eradicate so many demerits in comparison to other censorial mammals. Carrier presented the confinements imposed by their rate of energy use is counteracted by the development of human physiology and this indicates an evolutionary preference for endurance running.
The critics praise Carrier for elaborating his argument in a skillful and convincing manner. Most of the comments relate to peripheral matters however a few attack on the basic hypothesis of the Carrier. The supposition of Carrier that the human thermoregulatory system evolved in response to the supplemented heat load of endurance running is thought to be unnecessary since less exhaustive activities may be adequate reasons for this specific hominid development. Another critic is not convinced of the fact that the endurance running was a basic selective force in hominid evolution. Some critics also attack the failure of Carrier in analyzing the other modes of hominid subsistence aside from hunting such as gathering scavenging. According to Carrier perseverance hunting most probably have contributed significantly in evolutionary selection than scavenging and gathering because persistence hunting placed hominids in an unrivaled discriminating position.
Moreover, scavenging and gathering would not have necessitated the specialization of the hominid thermoregulatory system that distinguishes it from all other mammals. For the thermoregulatory system water is considered to be essential for effecting operation during endurance predation and the relative inability of hominid to store water is conceded as one of the significant problems. It has also been believed that these physiological adjustments must have contributed to make endurance predation a feasible and cost effective method of hunting alternatively this technique would not have been resorted to. Since this is an article which appeared in a journal 'Current Anthropology' which has been referenced thoroughly the information is accurate and reliable.
Broker, Stephen P. 'Hominid Evolution' Yale-New Haven Teachers Institute. Available at http://www.yale.edu/ynhti/curriculum/units/1979/6/79.06.02.x.html. Accessed on 23 November, 2004
Carrier, David R. The Energetic Paradox of Human Running and Hominid Evolution. Current Anthropology. 1984 Volume: 25; No: 4; pp: 483-495. Available at http://www.publicanthropology.org/Archive/Ca1984.htm. Accessed on 23 November, 2004
Farabee, M.J. Human Evolution. Available at http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookHumEvol.html. Accessed on 23 November, 2004
Skybreak, Ardea. Part 6D: The Two Biggest Leaps in Hominid Evolution: The Science of Evolution, the Evolution of Human Beings. Revolutionary Worker. No: 1182, January 12, 2003. Available at http://rwor.org/a/v24/1181-1190/1182/evol6d.htm. Accessed on 23 November, 2004