Posts Tagged ‘early humans’
a wee piece on monogamy
So, back to the question of monogamy. Is Homo sapiens a monogamous species? If they are, how long have they been so? We know that neither chimps nor bonobos are monogamous (it’s very rare in primates generally), and we know very little – almost nothing – of the social lives of those extinct species that fill in the gaps between ourselves and Pan paniscus. Nor do we know anything much about the social lives of our own species going back 50,000 years and more. A fairly standard view, it seems to me, is that the rise of agriculture and the stable settlements that were part of this change promoted monogamous ‘ownership’ just as it promoted land ownership. But, as Joseph Henrich argues in The weirdest people in the world, powerful or large-scale landowners could also become large-scale people-owners too, in terms of wives and slaves. Polygyny was an elitist cultural thing, even if it has faint links with our gorilla ancestors.
So it’s fair to say that monogamy is more a cultural than a natural phenomenon, and so subject to variation. We can see this cultural effect in terms of our obsession with lineage and inheritance, generally along male lines. A culturally created patriarchal monogamy, with various exceptions, increasingly in the modern WEIRD world.
The general acceptance of monogamous norms puts pressure on individuals, as well as affecting their worldview, as they may, often unconsciously, take on the concept of a ‘right partner’, especially for breeding purposes. This goes along with ‘hearth and home’, much like the nest-building of most avian species.
I’m trying not to write this from an anti-monogamy perspective – frankly I’m not sure where I stand on the topic. Laissez faire might be the best description. Nowadays, again in the WEIRD world, we’re more conscious about how we’ve come to arrange things – nuclear families, home-making, and their alternatives, single parents, kibbutzim, two mums, two dads, and so forth, and we can even question the hearth and home arrangements, given our knowledge of bonobos in particular, with their broader supportive communities. Could it be that earlier human communities, those of Homo erectus and their immediate ancestors, were also more communal, in terms of sexual activity and child-rearing? Less possessive and jealous? Will we ever know?
And is our greater consciousness about monogamy having the effect of making us less monogamous? Bucking the trend? Is this really the best way to raise children? Of course it’s still generally seen as the norm, and the best – single-parent homes are ‘broken monogamies’, half-families. But we’re constantly evolving, learning new ways, considering other species – bonobos again. Their kids are so well-adjusted (funny expression, that).
We’re stuck in our own time, and history can’t teach us the future. Keeping options open is surely a key to survival so let’s not condemn other ways, let’s keep on searching and admiring, not just the best in human efforts, glimpses of utopia, but in those of other species….
References
https://www.sciencedirect.com/science/article/abs/pii/0140175079900010
Joseph Henrich, The weirdest people in the world: how the west became psychologically peculiar and particularly prosperous, 2020
modern humans are getting less modern, in unexpected places
Taken from the website of Science magazine
In recent years we’ve been almost overwhelmed by paleontological discoveries (and re-analyses of earlier discoveries), from giant worm jaws to a new subclass of cephalopod to a new semi-aquatic non-avian dinosaur to the oldest fossils yet found of that strange species, Homo sapiens.
I’ve decided to focus on the last example, for now. Homo sapiens fossils discovered at Jebel Irhoud in Morocco in the sixties, and long thought to have been some 40,000 years old, came under increasing ‘suspicion’ from palaeontologists, beginning in the eighties, due to various curious anomalies. More intensive searching at the Jebel Irhoud site recently has led to a wealth of discoveries, ‘including skull bones from five [human-like, though with a different brain-case, especially at the back] individuals who all died around the same time’. And thanks to the new thermoluminescence dating technique, which is applied to heated or burned substances (it’s a measure of accumulated radiation), a date of 300,000 years was calculated for the tools found near the fossils, and by association for the fossils themselves. This makes them over 100,000 years older than those found in Ethiopia. The Ethiopian fossil discoveries gave rise to the idea that ‘modern’ humans began life in a small region of East-Central Africa and gradually spread, but the revelation about the Moroccan fossils means a revision, or overturning, of that hypothesis.
You’ll notice I’ve put modern in skeptical quotes. It seems to me nobody will agree on what a modern human really is, or whether it’s decided entirely on anatomical or physiological features. If you found yourself suddenly transported to the days of Sargon and the Akkadian civilisation, only 4,500 years ago, you probably wouldn’t have the impression you were living among modern humans – depending on how prepared you were for the culture shock. Of course, paleontologists would have different measures for modernity – brain size, skeletal features and such – but these are necessarily imprecise given individual variation and the sparsity of really good fossils. And there’s also the matter of incremental, barely discernible change. For example, our 300,000-year-old Jebel Irhoud specimens are, perhaps, the oldest known modern human specimens, but it would be silly to argue that their parents weren’t just as modern – and what of their grandparents? And in this way we can go back another 10,000 years, or maybe 50,000, without seeing much difference. This has always been the most difficult thing to get my head around, not only for H sapiens but for any species. When does Australopithecus afarensis start/stop being Australopithecus afarensis? When did a chimp distinguish herself from a bonobo, and when did they both get differentiated from their predecessor? Are we taking hard and fast taxonomy too seriously? Maybe I’ll return to that some time…
Meanwhile, another recently revealed discovery has added to the ‘out of Africa’ confusion, which many thought was becoming less confused, with something like a consensus that H sapiens emerged from Africa between 70 and 100 thousand years ago and dispersed globally, with the oldest Australian human possibly dating back as far as 65,000 years.
The discovery of a human jawbone and teeth in Israel that date back nearly 200,000 years has messed up that simplifying story, and it’s only one of a number of finds that are making the experts get confused – and excited – again. The jawbone find, combined with sophisticated tools and weaponry, is solid evidence of H sapiens coming out of Africa much earlier, and perhaps on an irregular basis depending on climatic conditions and resources. Human teeth found in China, and human fossils in Sumatra, dating to at least 70,000 years ago, tend to confirm this hypothesis. Other fossil discoveries in Israel are complicating the picture. The Eastern Mediterranean seems to have been a crossroads where various early human species may have interacted.
These new discoveries appear to confound the genetic evidence that we’re all related to an out-of-Africa population that emerged well under 100,000 years ago, but it seems these early populations died out or returned to Africa.
Yet there are so many mysteries still to solve. What about the strange Denisovans? We have so little fossil evidence, yet enough to map almost the entire nuclear and mitochondrial genome – a testament to modern technology. Analysis of their mtDNA suggests that they migrated out of Africa much earlier than the modern humans above-mentioned, but later than H erectus. They apparently branched off from the human line 600,000 years ago, and from Neanderthals about 400,000 years ago. The fullness and fascinating richness of the Wikipedia article on the Denisovans, garnered from such minute fossil evidence, is a source of great wonder to me. The specimens (of four distinct Denisovans) were well preserved due to the icy temperatures in the Siberian cave, near the Mongolian-Chinese border, where they were found. The finger bone, dated to about 40,000 years BP (Before Present, a new designation to me, and a welcome one), has yielded both mitochondrial and nuclear DNA, which has shown the Denisovans to be distinct from both Neanderthals and modern humans, and that they share a common ancestor with Neanderthals. Other excavations of the cave show that it was inhabited at least 125,000 years ago. mtDNA analysis has apparently revealed that the three, H sapiens, Denisovans and Neanderthals, shared a common ancestor about 1 million years ago. I’m writing these facts, if they are facts, as I find them, while wondering what they mean, and especially how the evolutionary tree can be visualised, but it’s pretty difficult, especially when you consider interbreeding. Looks like I’ll have to write and do the research for half a dozen posts before I start to get it straight in my own head. Anyway, here’s one interesting chart I’ve found.
There are clearly more mystery hominids to be found, to fill out the complicating picture. And of course I’ve mentioned the genetics and genomics only in passing, but again it’s astonishing what they can find these days by comparing these genes with what we know of some modern human populations. For example, studies of the Denisovans genome found ‘a region around the EPAS1 gene that assists with adaptation to low oxygen levels at high altitude’, already known from analysis of modern Tibetan genes.
Hoping to keep myself up to date with all this, if I don’t get too distracted by the zillions of other fields of enquiry worth keeping up with…
References
https://en.wikipedia.org/wiki/Denisovan
All the excitation about Trump having tried to sack Mueller annoys me because it makes me – well, too excited. I have to learn to be patient. The Mueller enquiry will end when it does, and it’s sure to end dramatically. Still, I hunger for another indictment, or equivalent headline. One point worth worrying about though, is what happens when Trump goes? The whole administration should go, but that’s not what happens in the US. No snap elections, no double dissolution. Another weakness of the Presidential system, it seems to me. In the US, you vote for a personality, and that personality gets to build a team around him (it’s always been a bloke), whereas in most advanced western nations, the country’s leader has risen through the ranks of the team, much like the captain of a soccer team, who’s given the captain’s armband, not because she’s the best player – though she quite often is – but because she’s the most inspiring leader. If that captain falls afoul of the law, another competent team member can take on the job. In the case of the US Presidency, the team is tainted by the captain’s failings because he’s personally chosen the lot of them – in this case largely because of their political ignorance, which he regards as a positive.