The Mid-Brunhes Transition

Discussion in 'Earth Science' started by sculptor, Jul 8, 2023.

  1. sculptor Valued Senior Member

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    Have you given any thought to The Mid-Brunhes Transition?
    Would you care to opine as to causality?
    It seems to have led to the climate(extended interglacial) of marine isotope stage(mis) 11.
    And, then, we have the potential for the 400(also 405 and 413)kyr cycle.
    Leaving us with a potential repeat of the climate of mis 11.
    during which we have Lee Berger's 7 foot tall heidelbergensis(or archaic Homo sapiens?)
    and..............then.....?

    Your thoughts?
     
    Last edited: Jul 8, 2023
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  3. exchemist Valued Senior Member

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    My thoughts are that this will most likely be, in some moronic way, a feeble attempt to undermine the science of climate change. As if the climate scientists won't have been aware of interglacial cycles until you came along. Or something.
     
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  5. C C Consular Corps - "the backbone of diplomacy" Valued Senior Member

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    In a broad sense, the causes fell out of obliquity deviations and the resulting solar insolation effects (as recruited and exemplified by the Milankovitch cycles). With contingent contributions from fluctuating greater and lesser biological activity affecting CO2 levels (along with ocean absorption). The former possibly an influential factor in Marine Isotope Stage 11.

    But a lack of sufficiently long records, especially at certain latitudes, makes more specific explanations highly speculative and diverse (without consensus). One analysis from well over a decade ago even questions the universal reach of it, suggesting "that the MBE is not a global climatic transition but is restricted to specific regions, in particular the higher latitudes of the southern Hemisphere. Further work is needed to understand the regional variability and cause of the MBE".

    A "7 foot tall heidelbergensis" is either myth, exaggeration, or if there were actual fossil remnants of such an individual -- it would still be highly suspect as an outlier (not reflecting a common characteristic of the majority).

    While there is the chronological coincidence between the environmental changes and human evolution (suggesting a link), there doesn't seem to be a robust smoking gun yet to solidly lift this from correlation to causation. Though migration into new areas and climate changes chaotically shaking-up the scattered populations off and on certainly beckons as an enticing recipe for modifications and adaptions.[1] Humans "proper" sprang from Africa rather than the Euro-Asian-Oceanic turmoil, albeit we do carry genes from archaic members in those regions.

    - - - footnote - - -

    [1] Population Bottlenecks and Pleistocene Human Evolution
    https://academic.oup.com/mbe/article/17/1/2/975516?login=false

    In spite of oscillating population sizes across the temperate zones everywhere, perhaps corresponding to the glaciations and their effects, the archaeological record reflects increased habitat specialization and continually larger population numbers worldwide. However, the oscillations were significant. For instance, both central/western Europe and southern Africa were largely depopulated in the Late Pleistocene, Europe several times...
    _
     
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  7. James R Just this guy, you know? Staff Member

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    No. Please explain what it is. It's like you've jumped into the middle of a discussion, without posting a thread opener.
    So what?
     
  8. sculptor Valued Senior Member

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    8,476
    ok
    7 feet tall-
    this courtesy of the naked scientist
    https://www.thenakedscientists.com/articles/interviews/our-story-human-ancestor-fossils
    here we have Lee Burger with part of a heidelbergensis femur

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    ergo: "during which we have Lee Berger's 7 foot tall heidelbergensis(or archaic Homo sapiens?)" (from above)
    "we found a lot of them. Everywhere we find them we find them enormous. These are what we call archaic Homo sapiens. Some people refer to them as Homo heidelbergensis. These individuals are extraordinary, they are giants."
    ...................
    more later
    Thanx for the John Hawks mnemonic
    (been awhile since I read his offerings)
     
  9. C C Consular Corps - "the backbone of diplomacy" Valued Senior Member

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    Yah, I'm well aware of that 2007 interview whose topic seems to absent anywhere else, aside from occasional puzzled inquiries referencing it.

    Let me know if you find a solid academic source or research paper of Berger's formally submitting a "routinely over 7-foot tall individuals" discovery and interpretation of it as a "period of giantism in Homo heidelbergensis" to the scientific community; as well as the latter's response to it. (Well, if the former existed, I might locate an instance of other scientists' evaluation using the title and publication date.)

    (2012) Scientists Determine Height of Homo Heidelbergensis
    https://www.sci.news/othersciences/anthropology/article00369.html
    PAPER: https://www.sciencedirect.com/science/article/abs/pii/S0047248411002193?via=ihub

    EXCERPT: According to the researchers, putting aside the margin corresponding to small biotype species like H. habilis (East Africa), H. georgicus (Georgia) and H. floresiensis (Flores in Indonesia), all documented humans during the Early and Middle Pleistocene Era that inhabited Africa (H. ergaster, H. rhodesiensis), Asia (H. erectus) and Europe (H. antecessor, H. heidelbergensis and H. neanderthalensis) seemed to have medium and above-medium heights for the most part of two millions years. However, the researchers state that “amongst every population we have found a tall or very tall individual.” [i.e., outlier]

    In their opinion, this suggests that the height of the Homo genus remained more or less stable for 2 million years until the appearance of a “ground-breaking species in this sense” in Africa just 200,000 years ago. These were the Homo sapiens, who were initially significantly taller than any other species that existed at the time.
    _​
     
    Last edited: Jul 11, 2023
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  10. billvon Valued Senior Member

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    OK. So?

    They are far shorter than the tallest guy in the US (8' 11".) There have been over a dozen people taller than 8 feet. There are thousands of people living today who are over 7 feet tall. Not sure why the past would be any different; in fact I'd expect a wider variety of heights given the various subspecies that make up early hominids.
     
  11. exchemist Valued Senior Member

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    Well this is splendid, taking the discussion far away from what I continue to suspect was the original, though naturally unstated, purpose of the thread. Keep it up.

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  12. Yazata Valued Senior Member

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    Tell the truth, I haven't. For those too lacking in scientific curiosity to do a simple search --

    https://en.wikipedia.org/wiki/Mid-Brunhes_Event

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    I have no idea. I will say that climatology still seems to me to contain many major unknowns. Such as what explains the observed (or rather inferred from evidence) cyclical/periodic glacial/interglacial excursions. I'd assume that the Mid-Brunhes event (should it prove to be real and of worldwide extent) probably has its explanation there. Whatever it was, it appears to have increased both the amplitude and the periodicity of the cycles.

    It certainly seems plausible to me to hypothesize that the intensity of these climate cycles played a role in the evolution of Homo sapiens. I don't know enough to say more about what that role might have been or how Homo heidelbergensis fits into the big picture.

    (As you know, I strongly suspect that human evolution was far more complex than the rather simplistic accounts found in many textbooks today.)
     
    Last edited: Jul 16, 2023

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