Avatar said:
Sorry, this is a copy from the BBC science news, but it seems worthwhile to direct your attention to this discussable topic.
Could it be that first we walked like those children on palms with fingers free,
and then later, as we found more use for fingers, progressively abandoned the walking on all four?
It seems quite an interesting proposal that such use of hands could have been a transitional stage what later resulted in bipedal movement.
http://news.bbc.co.uk/2/hi/science/nature/4782492.stm
This report has been floating around the internet and the general media for a few weeks now. This is the third thread on Sciforums on it. Unfortunately, not many people seem to realize that it’s very poor science and not worthy of any serious consideration.
I realize that “published” and “peer-reviewed” data is often held up in science forums (indeed, in the science field itself) as the benchmark for the validity of evidence, but nonetheless you have to be careful. Not all “published peer-reviewed” data is worthy of consideration. This is a good case in point.
This paper in question regarding this supposed “reverse evolution” was published in the
International Journal of Neuroscience. That sounds impressive but a little investigation reveals that this journal is ranked 175th out of 198 journals in the field of neuroscience with an impact factor of 0.579. The ‘impact factor’ is a weighted score that indicates how many times articles in the journal are referenced by other papers in other journals, thus providing an indication of the relevance and significance of the journal’s content. Its score 0.579 is very low. So the takehome message is this – people can publish poor quality research in this journal that would otherwise
not be accepted in other higher-quality journals. This is immediately obvious when you actually read through the paper in question. (It is available free of charge from the journal website.) The fact that he is editor of this very journal is somewhat suspicious!
The author has concluded that this is a new syndrome resulting from an autosomal recessive allele. Whilst it is true that the number of offspring with the phenotype (5 in 19) is suggestive of an autosomal recessive phenotype, as a geneticist I can say that there is no way you can conclude this from a single cross (ie. in this case, the progeny from a single pair of parents). You need multiple crosses across multiple generations, and in-crossing and back-crossing (ie. sibling-sibling and parent-sibling crosses) before you can confidently conclude the Mendelian inheritance pattern of any given phenotype. The author has no such data and thus, in the absence of <I><B>any</B></I> genetic data other than a single cross, it is erroneous to conclude that this represents a new syndrome. From the extremely limited data it’s just as likely that the cause is environmental rather than congenital.
He states that there were MRI and CT scans performed but no figures were included. Why not?
The bulk of the paper was taken up with an analysis of their gait and mental abilities. Numerous parallels were drawn with other animals but no references were included to substantiate any of the comparisons. The conclusion was that the five people in question have a “…quadrupedal palm-gait, severe mental retardation, primitive speech, and disturbed conscious experience.”
Okay, fair enough. That statement of findings is not very debatable from the data. It’s the wild and unsubstantiated conclusions the author subsequently draws from these simple findings that make this whole paper a complete joke. There is only a single reference for the entire paper and it appears to relate to the brain structure and cognitive analysis that was performed. There are no references at all to substantiate any of his numerous evolutionary musings in the introduction and the discussion. From his physiological analysis of a single family he starts speculating on the evolutionary coupling of gait, brain size, speech, intelligence and consciousness!
"The present work describes a new syndrome, and its relation to human evolution, especially with regard to transition from the habitual quadrupedality to habitual bipedality".
Bollocks! There’s no concrete evidence that the phenotype is genetic in the first place, let alone has anything to do with the evolution of bipedal gait. Such evolution is bound to involve a number of genetic alterations, not just a single gene.
In short, this is one of the worst published papers I have ever seen. I hope the mass media doesn’t give it too much publicity.
Just I case there was any doubt, here are further examples of his unsubstantiated hand-waving from the paper…..
The genetic nature of this syndrome suggests a backward stage in human evolution, which is most probably caused by a genetic mutation, rendering, in turn, the transition from quadrupedality to bipedality. This would then be consistent with theories of punctuated evolution. On the other hand, the extensor motor system causing a resistance of the body against the gravity may actually be subjected to evolutionary forces. This new syndrome may be used as a live model for human evolution.
As generally known, human beings are unique in articulated speech, habitual bipedality, and high intelligence as well as the conscious experience. The transition from quadrupedality to bipedality, that is, the ability to walk habitually on two legs, is the most important stage in human evolution. This is taken as the most important, first step, predating the other uniquely human traits.
The emergence of an upright posture suggests a psychological resistance —resistive mind—of our ancestors against the very strong gravitational forces of earth on which they live. The resistive mind apparently co-evolved with increasing brain size. A large brain in our ancestors seems to be coupled with resistive behavioral traits, which were probably the triggering factors for the emergence of homo erectus, that is, habitual upright posture with bipedal gait. Thus, the author maintains that there was first the free will as a main trait of the large brain, equipped with an intelligent struggle for human survival. The resistive human mind against the earth‘s gravitational forces is still in action, despite having the habitual erect posture since millions of years. As a result, not only are humans habitually standing up on two feet, they are even completely freed from the gravitational forces, and walking within the depths of the endless space. In light of these considerations, this article describes a new syndrome with quadrupedal gait, primitive speech, severe mental retardation, and disordered conscious experience. This syndrome, apart from being a rare neurological disease, may elucidate the human evolution, with gradual or punctuated emergence of human beings.
The present work described a new syndrome exhibiting a habitual palm-gait, primitive speech, severe mental retardation, and severely impaired conscious experience. This genetic disorder suggests a backward stage in human evolution, following a sudden mutation(s) (punctuated evolution), not resulting from a slowly occurring gradual evolution. Accordingly, this new syndrome suggests, as a live model for human evolution, that first of all a human-specific resistive mind coupled with a relatively large human brain emerged during the human evolution. These human beings resisted the earth’s gravitational forces as a result of the evolution of the extensor motor system, which was the actual driving force for humankind including the upright posture against gravity. This psychomotor drive is still in action, causing humans to be completely free from the earth‘s gravitational forces, even reaching the deepness of endless space.
Pffft!
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