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#124691 - 05/18/06 01:45 AM
Re: Creation or evolution
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Regular
Registered: 05/16/06
Posts: 81
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[quote]Originally posted by PDM:
[b] Hi Deborah. Welcome.
Yes, thank you - that's really interesting.
I have read that the development of language has had an enormous effect on the general development of our species.
Any idea when [i]we[/i] started talking, as opposed to communicating in the same way as other primates do?
Do you know if gorillas and chimps still have that 'narrow opening through their vertibrae'?
Fascinating! [/b][/quote]Hello Again PDM! I am so happy I bookmarked this link. :)
I am no expert on the matter but I can share with you what I have learned. Apparently the impetus for the evolution of language is believed to have occurred when human ancestors left the security of the forest, became bipedal and started foraging on the savanna. The need to pass on information was the driving force, such as alarm calls and other expressions. For instance, foragers would have had to report back to others what they had found.
The present molecular data strongly supports a common origin for all extant humans somewhere around 100,000 -200,000 years ago. The so called "Mitochondrial Eve", the putative common ancestor of all women, was at the forefront of this molecular wave, but she has since been joined by a corrosponding Y-Chromosome Adam as well as by data from non sex genes and from X-chromosome. It follows that the origins of language cannot possibly be more recent than 100,000 years ago. This conclusion is consistant with the archaelogical evidence of migration out of Africa to various continents.
The vocal tract itself is all soft tissue and does not fossilize, but its shape is connected with the surrounding bones, the skull base and the hyoid. Already homo erectus had a near-modern skull base, but the significance of this is unclear. Hyoid bones are very rare as fossils, as they are not attached to the rest of the skeleton, but one Neanderthal hyoid has been found very similar to the hyoid of modern man, leading to the conclusion that Neaderthals had a vocal tract similar to our own.
Yes, gorillas and chimps still have the narrow opening in the spine as well as many other physical differences.
I refer you to an article (below) that I found very informative. This therory is still widely debated however.
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Recently, a partial spinal column attributed to Homo erectus was discovered at the site of Dmanisi, Georgia (Meyer 2005). Dated to 1.78 million years before present, the Dmanisi vertebrae are the oldest known for the genus, and present an important opportunity to examine the spinal anatomy and neuroanatomical potential of early Homo.
Comparative analyses against 2,257 human, chimpanzee and gorilla vertebrae demonstrate that the shape and size (absolute and size-corrected) of the Dmanisi spinal cord in the cervical, thoracic, and lumbar regions would have matched that of modern humans. This contrasts with the only other spinal column known for early Homo, the Nariokotome specimen (KNM-WT-15000), which exhibits evidence for a small and apelike spinal cord. The Nariokotome specimen suggested to some workers that early Homo lacked a human level of innervation to respiratory muscles involved in spoken language, and was therefore, incapable of producing spoken language. However, this study unequivocally supports suggestions that the KNM-WT-15000 vertebrae exhibit a developmental pathology known as neural stenosis, and is not representative of the taxon (Latimer & Ohman 2001; Meyer 2003). Moreover, this pathological condition may have conferred chronic health and locomotor difficulties in the Nariokotome individual, precipitating a considerable degree of assistance from conspecifics. In contrast, a quarter-million years before the birth of Nariokotome, Homo erectus at Dmanisi had already evolved a fully human postcranial neuroanatomical substrate associated with the control of respiratory muscles involved in spoken language. Thus, both altruism and spoken language may have been part of the behavioral repertoire of early Homo.
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Latimer, B, and Ohman, J. 2001. Axial Displasia in Homo erectus. Journal of Human Evolution 40: A12.
Meyer, M. 2003. Vertebrae and Language Ability in Early Hominids. PaleoAnthropology 1: 20–21.
Meyer, M. 2005. Functional Anatomy of the Homo erectus Axial Skeleton from Dmanisi, Georgia. Ph.D. thesis. Philadelphia: Department of Anthropology, University of Pennsylvania.
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