human evolution

Discussion in 'Human Science' started by Pratik Chakraborty, May 31, 2010.

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  1. Pratik Chakraborty

    Pratik Chakraborty Registered Member

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    why human evolution showed reverse trend in respect of cranial capacity from Cro mangon to modern man?
     
    Pratik Chakraborty, May 31, 2010
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  3. baftan

    baftan ******* Valued Senior Member

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    Do you mean the decrease in overall volume of the skull? And what do you mean by "reverse"?
     
    baftan, May 31, 2010
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  5. davewhite04

    davewhite04 Valued Senior Member

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    That sounds like what he means.
     
    davewhite04, May 31, 2010
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  7. Fraggle Rocker

    Fraggle Rocker Staff Member

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    I think it was displacement rather than evolution. The Cro-Magnons were a local population of our species, Homo sapiens. In other words, they were "modern man." As is often the case with local populations, they had a few genetic traits that differentiated them from other populations, but not so greatly as to be considered a distinct subspecies. One of those traits was slightly larger cranial capacity.

    They were the first group of Homo sapiens to migrate from Asia into Europe, reaching France around 30KYA. But they were not the only group. Other populations of Homo sapiens migrated into Europe in later eras, populations that did not have the larger cranium.

    For reasons we may never understand, the later arrivals came to dominate the continent, displacing the Cro-Magnons. However, a typical reason for this phenomenon, which has occurred in many parts of the earth in many eras, is that the newcomers were part of a larger community that was making greater technological progress than the poor isolated Cro-Magnons. So when they arrived in Europe they had better tools, weapons, clothing, organization and knowledge of nature, and were better able to master the environment, marginalizing the original inhabitants. This is, after all, exactly how the modern Europeans displaced the Native Americans, Australians, and other peoples.

    There were multiple waves of migration from Asia into Europe. The Neanderthals of course came first, a different species of human. Then came the Cro-Magnon, the first Homo sapiens. They were followed by more migrations, probably at least two more and very likely more than that. European DNA shows traces of Neanderthal genes and also genes from other Homo sapiens tribes that predate the arrival of the Indo-European (Celtic, Germanic, Hellenic, Italic and Slavic) tribes, for example the people who built Stonehenge before vanishing when the Celts arrived in Britain.

    The Wikipedia article on the Cro-Magnons says some anthropoligists suspect that the Basques--the only surviving pre-Indo-European people in Europe--may be descended from the Cro-Magnons.
     
    Fraggle Rocker, May 31, 2010
    #4
  8. davewhite04

    davewhite04 Valued Senior Member

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    Wikipedia suggests that they were an early form of us, by some 35K years... before now. This doesn't sound like they were "us".
     
    davewhite04, May 31, 2010
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  9. davewhite04

    davewhite04 Valued Senior Member

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    Maybe having a larger cranial capacity was not needed...

    Purely guessing, not my area of expertise

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    davewhite04, May 31, 2010
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  10. Pratik Chakraborty

    Pratik Chakraborty Registered Member

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    where basques resides? What are their IQ level?
     
    Pratik Chakraborty, May 31, 2010
    #7
  11. mathman

    mathman Valued Senior Member

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    Basques live in northwestern Spain (just south of the Pyrenees).
     
    mathman, May 31, 2010
    #8
  12. baftan

    baftan ******* Valued Senior Member

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    What do you mean by that? What is the relation to the topic?
     
    baftan, May 31, 2010
    #9
  13. Fraggle Rocker

    Fraggle Rocker Staff Member

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    Our species is 200,000 years old. That makes the Cro-Magnon a rather late form of "us," not an early one.

    AFAIK no one has suggested that they should be classified taxonomically as a separate subspecies of Homo sapiens. This means that the differences between them and "us" are minor and that we would have no reservation about interbreeding with them. If the Basques do indeed carry some Cro-Magnon DNA--which I don't think has been mapped yet so we don't know for sure--then that is exactly what happened when the next wave of culturally and technologically more advanced humans moved into their territory.
    He jumps to the obvious conclusion that if their cranial capacity was larger then they had larger brains, and that should have made them more intelligent than us.

    Considering that the standard deviation in our IQ is enormous and you meet people every day with IQs of 80 and 120, I'm not sure the slight advantage of a larger brain would result in a statistically significant superiority.
     
    Fraggle Rocker, May 31, 2010
    #10
  14. nietzschefan

    nietzschefan Thread Killer Valued Senior Member

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    The Immigrants came into western Europe around 25KYA under the banner of multiculturalism and ruined it.
     
    nietzschefan, May 31, 2010
    #11
  15. Fraggle Rocker

    Fraggle Rocker Staff Member

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    Oh I don't know. I think Europe turned out to be a rather nice place.

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    Fraggle Rocker, Jun 1, 2010
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  16. Skeptical

    Skeptical Registered Senior Member

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    There is no statistically significant data to demonstrate Cro-magnon had larger brains than modern man. That is because too few fossils have been found able to give an accurate measure of cranial capacity, and to show accurately how much it varied from individual to individual. The greatest probability is that their brains were the same size as that of modern man.

    Modern man has a brain size that varies quite substantially. Normal range is 1200 to 1400 cc, but up to 1600 is not uncommon. I am not aware of any data that clearly shows the larger brains belong to smarter people.

    Interestingly, enough neanderthal fossils have been measured to show they, on average, had a larger brain than modern man. Again, by a small margin.
     
    Skeptical, Jun 1, 2010
    #13
  17. Hercules Rockefeller

    Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    This report suggests that although differing brain morphologies can be derived from fossil endocasts, it is difficult to draw functional inferences from such data. However, it seems that functional inferences can be made for the cerebellum, and that the ratio of cerebellar size to cerebral size can be informative for investigating changes in computational efficiency through hominid evolution.

     
    Hercules Rockefeller, Jun 1, 2010
    #14
  18. DNA100

    DNA100 Registered Senior Member

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    We have become more abstract thinkers.May be that's why.

    Dolphins,whales etc all have larger brains than us.
    Most of the brain-size is related to body movements and spatial memory.
     
    DNA100, Jun 3, 2010
    #15
  19. Hercules Rockefeller

    Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    They do? Can you provide a reference for that statement? Are you talking about absolute size or relative to body size?


    Are you referring to hominids? If so, then I don’t think that’s correct. The most notable change in brain development through evolution from apes to hominids is the proportional increase in size of the cerebrum (especially the cerebral cortex) relative to the rest of the brain (eg. cerebellum). The cortex is mostly responsible for higher cognitive functions, not motor control or memory.
     
    Hercules Rockefeller, Jun 4, 2010
    #16
  20. DNA100

    DNA100 Registered Senior Member

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    I think may be you just google it a bit.
    Well,here is a random one

    http://www.seaworld.org/infobooks/killerwhale/conservationkw.htm

    read this part:
    In fact ,the size of a killer whale's brain is as big as the whole human head,not just the brain.
     
    DNA100, Jun 5, 2010
    #17
  21. John99

    John99 Banned Banned

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    Brain size is not the best way to gauge intelligence. Look at the size of a small marine fishes brain. Some are smaller than a pea yet they are very intelligent if you compare them to some large animals there really is little difference afa ability to make decisions.
     
    John99, Jun 5, 2010
    #18
  22. spidergoat

    spidergoat pubic diorama Valued Senior Member

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    Bigger Is Smarter: Overall, Not Relative, Brain Size Predicts Intelligence

    ScienceDaily (May 20, 2007) — When it comes to estimating the intelligence of various animal species, it may be as simple measuring overall brain size. In fact, making corrections for a species' body size may be a mistake. The findings were reported by researchers at Grand Valley State University and the Anthropological Institute and Museum at the University of Zürich, Switzerland. "It's long been known that species with larger body sizes generally have larger brains," said Robert Deaner, assistant professor of psychology at Grand Valley and the first author on the study. "Scientists have generally assumed that this pattern occurs because larger animals require larger nervous systems to coordinate their larger bodies. But our results suggest a simpler reason: larger species are typically smarter."

    http://www.sciencedaily.com/releases/2007/05/070518172103.htm
     
    spidergoat, Jun 5, 2010
    #19
  23. River Ape

    River Ape Valued Senior Member

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    Surely the fact that men are on the whole so much more intelligent than women provides the most manifest demonstration that brain size is the crucial factor.

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    River Ape, Jun 5, 2010
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