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Tuesday, June 05, 2018

Evolution of Brain/speech

This is a subject that needs a basic understanding of biology and neurology before you go on further
   We are all familiar with Darwin's theory (there was some similar thinking among some Muslim scientists of the "golden period of Islamic civilization" but none of them had the acute observational opportunity of Darwin and his ability to put it together in a plausible theory) of evolution how Humans have descended from Monkeys etc. but this theory is sorely lacking in one thing, the explanation of a speaking', criticizing, formulating, intelligent man, that almost "suddenly" comes up after the bipedal hominoids, in evolutionary process

    Let me explain very briefly what I am trying to say:
 Following the principles of "survival of the fittest" and positive selection for developmental adaptation etc. scientists have traced how in the family "Hominidae" all the genera and species developed over millions of years. The study has given us from Homo Sapiens the hominoids starting from "homo erectus" and we are looking at "homo sapiens sapiens" (HSS) You go through the study of changes in the limbs and pelvis, for example, in the musculo-skeletal arrangements/changes in adapting to the bipedal locomotion.  Here I will concentrate on the changes (or better), adaptational alterations in the brain only.
 Data/knowledge collected from fossils (found in Africa and some in Europe) does not give us all the information to connect everything nicely in the phylogenetic scales but the information does give us a clue as to how changes in the brains of Chimpanzees and then up to HSS etc. right up to the humans are developed. Here I will make some brief quotes from the late Sir John Eccles book, "Evolution of the BRAIN, Creation of the SELF" :
" With respect to auditory pathway up to primary and secondary Auditory areas of cortex, NO CHANGE has been reported in the evolutionary sequence from monkey to ape to human."
"Brains of HomoHabillis (Hominoids) there was not only fullness evident over the inferior frontal lobule (precursor of Brocas) but it was also evident in the inferior parietal lobule indicating that phylogenetic development of areas 39-40 (precursor of Wernicke) had already occured"
     Next note this:
( Geschwind), .....He also made suggestion  that area 39 (Angular Gyrus) has special function in speech since it developed at the meeting place of visual and tactile information. . . . . . .  it would thus be specially fitted for the identification and naming of objects observed both visually and tactually. "
  I will skip the evolutionary development of organs related to speech production (throat, tongue jaws etc.) and go to Evolution of the language process itself.
   "It is suggested then that Habilis had both the neural basis and anatomical capacity for speech albeit probably neither the structural nor the functional complex had attained the evolutionary advancement of today's people"
  OK; Now the speech as  we know it has three aspects, The Lexicon, the Syntax, and the Semantics. That is the vocabulary and their synthesis with each other to make a sentence and then the meaningfulness of it.(Example)
"Colorless green ideas sleep furiously" (a sentence making no sense  without semantics)
 Near 'relative' of Man, the apes, show no such human ability.  Then "there was apparently a clear QUALITATIVE difference between human and ape languages."
   Four forms/levels of language:
1. Expressive or symptomatic - like ability to make words
 2. Signaling function - like being able to send a signal to a receiver who can accept/understand it
 3.Descriptive function -  ability to describe which is the main human function of speech
   4. Argumentative function. - probably just extension of the above, the highest speech function

 Here we can see the first two (lower) levels animals like apes etc also have but  3 and 4  are limited to humans only. All kinds of experiments have been performed to teach (for example) Chimpanzee brain (a little female was literally brought up with humans only and taught language like a daughter) yet the expressions of human beings were not  reproduced.  Chimps are the closest to human brain and the sensory and motor areas are seen on the cortex and yet no speech like humans (that is remain limited to #  1 &;2 and not progress to #3&;4)
Now I wish for you to look at Norman Gecshwind's (very well-known expert neurologist-authority- on speech) words above and one can easily see  how the ability to see, feel and remember the names form the basis of "intelligence"
 That reminds us how Qur'an majeed describes the first human created by God who purposefully DEMONSTRATED THAT ABILITY OF MAN (ADAM) that he answered the question "Can you name these things?" and he told the (other creations (Angels and Jinns)  NAMES OF THINGS
  (Now I have just tried to simplify everything in order to be brief)

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