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Earth Science

Origin of Modern Humans 'Traced To Botswana' (bbc.com) 67

Posted by BeauHD from the ancestral-heartland dept.
dryriver shares a report from the BBC: Scientists have pinpointed the homeland of all humans alive today to a region south of the Zambesi River. The area is now dominated by salt pans, but was once home to an enormous lake, which may have been our ancestral heartland 200,000 years ago. Our ancestors settled for 70,000 years, until the local climate changed, researchers have proposed. They began to move on as fertile green corridors opened up, paving the way for future migrations out of Africa. "It has been clear for some time that anatomically modern humans appeared in Africa roughly 200,000 years ago," said Prof Vanessa Hayes, a geneticist at the Garvan Institute of Medical Research in Australia. "What has been long debated is the exact location of this emergence and subsequent dispersal of our earliest ancestors." Prof Hayes' conclusions have drawn scepticism from other researchers in the field, however. The area in question is south of the Zambesi basin, in northern Botswana. The researchers think our ancestors settled near Africa's huge lake system, known as Lake Makgadikgadi, which is now an area of sprawling salt flats. "It's an extremely large area, it would have been very wet, it would have been very lush," said Prof Hayes. "And it would have actually provided a suitable habitat for modern humans and wildlife to have lived." After staying there for 70,000 years, people began to move on. Shifts in rainfall across the region led to three waves of migration 130,000 and 110,000 years ago, driven by corridors of green fertile land opening up.

However, the study, published in the journal Nature, was greeted with caution by one expert, who says you can't reconstruct the story of human origins from mitochondrial DNA alone. Other analyses have produced different answers with fossil discoveries hinting at an eastern African origin. Prof Chris Stringer of the Natural History Museum, London, who is not connected with the study, said the evolution of Homo sapiens was a complex process. "You can't use modern mitochondrial distributions on their own to reconstruct a single location for modern human origins," he told BBC News. "I think it's over-reaching the data because you're only looking at one tiny part of the genome so it cannot give you the whole story of our origins." Thus, there could have been many homelands, rather than one, which have yet to be pinned down.
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Origin of Modern Humans 'Traced To Botswana' More

Origin of Modern Humans 'Traced To Botswana'

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  • On an article like that you'd imagine they'd put a map or something. But nooooo....

  • Aquatic Ape theory...? (Score:5, Interesting)

    by taiwanjohn ( 103839 ) on Tuesday October 29, 2019 @04:36AM (#59357516)

    enormous lake, which may have been our ancestral heartland 200,000 years ago.

    That would comport with the Aquatic Ape Hypothesis [wikipedia.org] of human origins. In particular, it fits with the well-established theory of recent ice ages, which date back to that period. So why don't we have fossil evidence? Well, if humans went through a transformative period in that time frame in coastal areas, then it would have happened when those coastal areas were on land that is now under a couple-hundred feet of ocean water.

    Before the most recent thaw about 10~12k years ago, we have a couple hundred thousand years of human development wherein all of the coastal regions are now under water, and therefore inaccessible to archaeological exploration. Even now, the vast majority of humans live near the ocean, so there's no reason to think it wouldn't have been the same back then.

    • Re: Aquatic Ape theory...? (Score:5, Informative)

      by samkass ( 174571 ) on Tuesday October 29, 2019 @05:18AM (#59357564) Homepage Journal

      Except that this theory states they were all living by a huge inland lake which has mostly drained since then.

    • Re: (Score:2)

      by rtb61 ( 674572 )

      So they base their discovery without ever having inspected ice age coastal plains and they are there for the majority of the time, we are in the shorter warm time period. I would look for the origins well, out under the sea, probably something like 200m down and under a bunch of mud and sand. In fact probably more advanced relatively speaking societies are all drowned out there.

    • Re:Aquatic Ape theory...? (Score:5, Insightful)

      by Zocalo ( 252965 ) on Tuesday October 29, 2019 @05:29AM (#59357590) Homepage
      Fossils are actually very fragile and, given how many creatures have lived throughout Earth's history, are proportionately *extremely* rare. They require quite specific conditions to form in the first place, then that the rocks they are in are not subducted, eroded, suffer from faulting, or are otherwise destroyed at any point over a period of eons and - after all that - that they end up close enough to the surface for us to find them.

      Public perception seems to be be that we have many complete and fully intact fossils of human ancestors; the reality is that we have entire sub-species, covering tens of thousands of years of localised evolution, that are only represented by a handful of fragments. Huge gaps in the fossil record, with entire species and maybe even entire branches of the tree of life leaving no record at all, is actually to be expected.
      • I was thinking the other day about what fossils would look like now: most of the mammalian biomass is livestock, and we don't tend to let them rot in the field. Human remains are either cremated or buried in a manner I'm not sure about how conducive it is to fossilization. So I might think it'd look like all the megafauna were suddenly gone, some chemical evidence of industrialization, with occasional mass graves of large apes and, depending on the time scale, landfills might leave something behind.

        • Re:Aquatic Ape theory...? (Score:5, Interesting)

          by Zocalo ( 252965 ) on Tuesday October 29, 2019 @09:21AM (#59358002) Homepage
          I recently read an article by a paleontologist making a point about the sheer egotism in calling our current "epoch" the Holocene in that our entire civilization, from the earlist suspected permanent settlements right through to present day, is still barely a blip on the geological radar; other epochs span tens, and even hundreds of millions of years. If our civilization were to suddenly collapse as a result of some natural or man-made calamity a future paleontologists working, tens or hundreds of millions of years from now, probably wouldn't really have all that much to go on to piece together what might have happened. Chances are actually pretty high that they would probably note the sudden (but very brief) spike in unusual chemical deposits, maybe even note other geological records pointing to a sudden shift in the climate, and realise that something unusual must have happened, but then move on without even realising that a space-faring civilisation had even existed.

          One slightly interesting corollary from that hypothesis is that if the dinosaurs had developed a similar level of civilization immediately prior to the asteroid strike, the chances are equally high that we'd be struggling to find any evidence of the fact as well. (FWIW, the author didn't think that scenario was very likely, just not possible to definitively rule out).
          • I don't think it is egotism, it'll be at least as notable as the K-T boundary, maybe more so with the large scale excavations that are unprecedented geologically. Sure, some of them will get smeared into a centimeter on a canyon wall but the mountain top removal style mining will be noticeable for at least a few hundred million years. I googled this up and at least some of our industrial output seems likely to fossilize: https://www.sciencemag.org/new... [sciencemag.org]

          • Re: (Score:1)

            by spun ( 1352 )

            Given the rate of extinction, pollution, and climate change, this epoch will be easily discernible in the geological record for billions of years to come.

          • Re: (Score:2, Flamebait)

            by Tim the Gecko ( 745081 )

            I recently read an article by a paleontologist making a point about the sheer egotism in calling our current "epoch" the Holocene in that our entire civilization, from the earlist suspected permanent settlements right through to present day, is still barely a blip on the geological radar

            If that was The Anthropocene Is a Joke [theatlantic.com] by Peter Brannen, then you should also look at What Made Me Reconsider the Anthropocene [theatlantic.com] by the same author. He listened to his critics, and now says "Whether our civilization is transient or not, its effects on the living world will last forever."

          • I recently read an article by a paleontologist making a point about the sheer egotism in calling our current "epoch" the Holocene...

            Sure - if you make too big a deal about the current era it's sheer egotism, if you don't make a big deal about it then you're deliberately downplaying the relatively large impact that humans have had on the environment in that short period of time.

            Like a lot of things, names of time periods are best made in hindsight, but we have to have a name for the current one, even if it's likely only a placeholder until (hopefully) our distant progeny can come up with a better one.

    • The aquatic ape theory is nonsense, and is unnecessary to explain anything.

    • Re: (Score:1)

      by papar ( 893096 )
      The aquatic ape theory is based on an observation that some physical attributes of humans seem to have been optimized with respect to aquatic surroundings. However, isn't the atmosphere a fluid just as any liquid? Fluid dynamics are pretty much the same, it's just the density that changes. Plus there's definately everyday interactions with liquids such as water, rain and sweat. Evolution optimizes everything it can, even the faintest traces of interactions with water become efficiently optimized and that's

      • However, isn't the atmosphere a fluid just as any liquid? Fluid dynamics are pretty much the same, it's just the density that changes.

        Which explains why whale and bat habitats overlap so much. /s

        Evolution optimizes everything it can, even the faintest traces of interactions with water become efficiently optimized and that's why we don't need to dwell in oceans to obtain "aquatic" features.

        Which explains why the great apes that live in the water-free rain forests are "non-aquatic", and the ape that evolved in the sopping-wet savanna is the one "aquatic" one. /s

        • Good God you are stupid. Nowhere did I claim that two species need to have identical features or behaviour. Also, bats are great swimmers. Humans lost their fur due to a number of reasons, and our better swimming ability is mostly a by-product of our weaker and less robust physique.

          • Nowhere did I claim that two species need to have identical features or behaviour.

            Correct. Where did I suggest that you did?

            Also, bats are great swimmers.

            Correct. So are a lot of primates. What does any of that have to do with the aquatic ape theory?

            Humans lost their fur due to a number of reasons, and our better swimming ability is mostly a by-product of our weaker and less robust physique.

            So being weaker makes primates better swimmers?

            Again, what does swimming ability have to do with the AAT?

    • That's exactly what sprung to mind when I read this. I know the theory doesn't sit well with a lot of people, but it seems logical to me, for a number of reasons: walking perfectly upright, lack of body hair, and well, people just seem to gravitate towards bodies of water, for recreation as much as drinking.
      People more versed in biology and evolution than I'll ever be both argue for and against the theory, so I'll just keep an open mind.

    • Re: (Score:2)

      by AHuxley ( 892839 )
      Re "time frame in coastal areas"
      Just add the super reed boat design... add more reed boats to the story and the out of Africa story still works..

  • Golgafrincham from "Hitchhiker's Guide" . . . ? (Score:5, Funny)

    by PolygamousRanchKid ( 1290638 ) on Tuesday October 29, 2019 @05:36AM (#59357600)

    From another free link to the story:

    https://www.bbc.com/news/scien... [bbc.com]

    The first migrants ventured north-east, followed by a second wave of migrants who travelled south-west and a third population remained in the homeland until today.

    This reminds me of Golgafrincham in "The Hitchhiker's Guide to the Galaxy":

    Golgafrincham was a planet, once home to the Great Circling Poets of Arium. The descendants of these poets made up tales of impending doom about the planet. The tales varied; some said it was going to crash into the sun, or the moon was going to crash into the planet. Others said the planet was to be invaded by twelve-foot piranha bees and still others said it was in danger of being eaten by an enormous mutant star-goat. These tales of impending doom allowed the Golgafrinchans to rid themselves of an entire useless third of their population. The story was that they would build three Ark ships. Into the A ship would go all the leaders, scientists and other high achievers. The C ship would contain all the people who made things and did things, and the B Ark would hold everyone else, such as hairdressers and telephone sanitisers. They sent the B ship off first, but of course, the other two-thirds of the population stayed on the planet and lived full, rich and happy lives until they were all wiped out by a virulent disease contracted from a dirty telephone.

    The only question is which group of early humans was Ark B . . . ?

  • However, the study, published in the journal Nature, was greeted with caution by one expert, who says you can't reconstruct the story of human origins from mitochondrial DNA alone.

    You don't say, lol. Yes, it's wild speculation.

    "Just so stories" indeed ...

  • Now SkyNet knows! (Score:5, Funny)

    by LostMyAccount ( 5587552 ) on Tuesday October 29, 2019 @08:05AM (#59357814)

    I look forward to the next Terminator franchise entry, where T-20000 is sent back to prehistoric Botswana to kill Sarah Connor once and for all.

    • Bring Bender along to "kill all humans"

    • Good joke, it was funny, but that would mean the terminators kill the creators before they could create skynet, your story falls apart quickly, or do we venture into alternative timelines rather than a single timeline like they've been playing it as?

      • Good joke, it was funny, but that would mean the terminators kill the creators before they could create skynet, your story falls apart quickly, or do we venture into alternative timelines rather than a single timeline like they've been playing it as?

        Huh? The Terminator franchise is practically nothing but alternative timelines.

    • Comment removed based on user account deletion

      • Re: (Score:2)

        by Wulf2k ( 4703573 )

        As long as the T-20000 didn't slowly lower itself into any pits of molten metal though, it wouldn't need to worry about its creator.

        It could just recreate a manufacturing base from scratch in the prehistoric era after killing the prehumans.

        I don't think Skynet's particularly attached to 'when' it exists.

  • Origin? (Score:3)

    by Muros ( 1167213 ) on Tuesday October 29, 2019 @09:16AM (#59357980)
    I doubt you can pin down the origin of modern humans to so small an area when we have fossils of almost modern humans from the other side of Africa that are 100ka older. https://www.nationalgeographic... [nationalgeographic.com]

    • They like the fame of "I found THE ONE" rather than accepting that lots of parallel evolutions happened in various regions and frequently merged.

      To be fair, though, there's more genetic variation within Africa than outside of it. A man from Norway and a man from Korea have more DNA in common than some people from different parts of Africa do.

    • Re:Origin? (Score:5, Interesting)

      by Sique ( 173459 ) on Tuesday October 29, 2019 @12:15PM (#59358676) Homepage
      But there are some good arguments for that. For instance, in that region, we have the languages with the most phonemes (Khoikhoi, San etc.pp.), with more than 160 different phonemes. There is some inverse proportionality between the number of phonemes a language has and the distance from Southern Africa (of which Botswana is a part of). The languages with the fewest phonemes are those of the polynesian branch of languages, with Hawaiian for instance having only 13 phonemes. European languages on the other hand have between 25 and 40 phonemes each. It would hint at a language evolution that started out with many phonemes. But with small groups leaving the place and only talking to each other, losing most complicated phonemes and thus streamlining their languages while being on their way.
    • I was wondering if anyone else would spot that gigantic spanner [nature.com] in these particular works.

      That's the problem with these genetics papers - they forget to look at non-genetic evidence like fossils.

  • MtDNA studies are 20 years old and only goes back 160 kya to a bottleneck. Whole genome sequencing has taken over and we have now sequence Human, Neanderthal and Denisovan DNA from hundreds of thousands of years ago. And even an ancestor of all of them H. heidelbergensis that is 440,000 years old. And we can measure the relatedness of genomes from 1 generation to hundreds of thousands of years and know that these groups migrated and interbred at times, as recently as 40 kya. mtDNA only goes back to bottl

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