an autodidact meets a dilettante…

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Posts Tagged ‘homo sapiens

a bonobo world 61 or so: some more species

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Gibbons – beautiful and imperilled

Canto: So if only we could quicken the modern world, which is so fast leaving behind the benefits of brute strength and embracing the strength of collaborative smarts… Well, maybe not that fast… We’d experience ourselves the loving fruits of bonobo-humanism.

Jacinta: Yeah, too bad. So let’s look more closely at other female dominated species, like elephants. They tend to value experience, so their family units have a female head.

Canto: Except that, they split into female and male groups, don’t they?

Jacinta: Well, they have these female family units, ranging from 3 to 25 members. The males presumably have their groupings, but sometimes they come together to form large herds or herd aggregations – huge numbers. Males can also be solitary, which virtually never happens with females. Of course it’s the females who raise the young, but there can be a lot of group solidarity.

Canto: It seems that the grouping changes more or less perpetually, seasonally, daily, hourly.

Jacinta: Yes, that’s a fission-fusion society, common among primates too – such as Homo sapiens at work, school, uni etc. But over time, the matriarch becomes more important, and presides over a wider network as she gets older. They play follow the leader as she has accumulated knowledge on the best watering holes, the paths of least resistance.

Canto: So elephants have it all worked out. What about those orangutans, what’s going on there?

Jacinta: Well apart from imminent extinction, there’s little to say. They’re solitary, though the Sumatran orang-utans are a little less so than those in Borneo, due to more food being available. The males exhibit hostility to each other and try to avoid each other, though they’re not territorial. They only hang out with females until they get their end away, and the females raise the offspring until they’re old enough to go solo.

Canto: So I wonder why the males are so much bigger than the females?

Jacinta: Yes they can be well over twice the size of the females. I haven’t found any explanation for it. They don’t have a harem of females to prove their rugged manliness. Apparently those big cheek pads help to attract the girls, but their huge bulk seems a bit superfluous.

Canto: Maybe it’s like whales – they grow big because they can. But then, the more you grow, the more you have to eat, presumably. A bit of a mug’s game.

Jacinta: Tell that to the elephants. Or those old ginorosauruses. Basically, if you’re as huge as an elephant, who else is going to attack you or compete with you? Apart from blokes with guns. But we were talking about sex. Or at least gender. Gorillas are proving a lot more complex than originally thought in their social structure – quite multilayered, not quite the chest-beating alpha male and his harem, more like human extended families. Matriarchies within patriarchies perhaps.

Canto: And what about gibbons – just to round out the primates. I know nothing about them.

Jacinta: Well, apparently these South-East Asian apes are monogamous, unlike other primates (except maybe humans, but I’m reluctant to rule on that). In fact only 3% of mammals are monogamous, according to a fact sheet I found (linked below). So that makes for family groups of two to six, just like our nuclear family, unless you’re a Catholic. Gibbons are considered as ‘lesser apes’, family Hylobatidae, unlike we great apes, family Hominidae. Physically, they’re by far the smallest of the apes, depending on particular species, but weighing at most about 12 kgs. These small family groups defend their territory aggressively – none of this fission-fusion stuff. They’re quite good at bipedalism, and present a good model for bipedalism in humans, but they’re also fantastically acrobatic tree-swingers, with the longest arms in relation to their bodies of any of the primates. They also have a nice healthy herbivorous diet.

Canto: They sound like a good human model all-round, and maybe a model for gender equality?

Jacinta: Well, yes, but I do prefer female supremacy. Gibbons are apparently the least studied of all the apes. There are 12 species of them, but many species are very near extinction, a fact not much known by the general public. Orangutans clearly get much more attention.

Canto: Okay so let’s look further afield – before coming back to human cultures to see if there are any matriarchies worth emulating. What more do we know about dolphins and other cetaceans?

Jacinta: Well, as you know dolphins live together in pods of up to 30, though sometimes where there’s an abundant food source they can form massive superpods of over 1000. And as we’ve learned, they engage in sex for fun.

Canto: I suppose also they could form superpods in the face of predators, like schools of fish.

Jacinta: Yes, possibly, though they wouldn’t have too many predators, unlike small fish. Interestingly these superpods can be made up of different cetacean species, so this would obviously benefit the smaller species. And individual dolphins can switch from pod to pod quite freely. Something like fission-fusion, but with greater flexibility. Researchers find this flexibility a sign of high intelligence.

Canto: Ahh, so that accounts for the stupidity of conservatives.

Jacinta: Some dolphin species are a bit more hierarchical than others, and you can see plenty of bite marks on bottlenose dolphins, evidence of fights for dominance.

Canto: And I recall a big hubbub a few years ago when those delightful creatures were discovered torturing and killing some of their own. But then, they are male-dominated, aren’t they?

Jacinta: They are, sadly. Males of all species are largely arseholes (well, not literally). But they certainly engage in a lot of play, I mean dolphins generally. Maybe they’ll evolve one day into a higher form of female-dominated life, but I doubt it. They’ll have to realise how fucked-up they are as a species to do that, like some humans have realised – but not enough.

Canto: Okay, so dolphins are out as a model. What about other cetaceans? I somehow suspect that orcas won’t fit the bill.

Jacinta: Next time. And we’ll look at some human models, if we can find them.

References

https://www.independent.co.uk/voices/comment/six-facts-about-elephant-families-9015298.html

https://seaworld.org/animals/all-about/orangutans/behavior/

https://orangutanfoundation.org.au/how-big-do-orangutans-get-learn-about-the-biology-of-the-orangutan/

https://www.sciencemag.org/news/2019/07/gorillas-have-developed-humanlike-social-structure-controversial-study-suggests

http://www.gibbons.de/main2/08teachtext/factgibbons/gibbonfact.html

Dolphin Social Structure

 

Written by stewart henderson

July 22, 2021 at 7:50 pm

a bonobo world 36: there is no bonobo nation

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nations, some say

Homo sapiens have been around for between 200 and 300 thousand years, depending on various theories and interpretations. I always like to point out that the ‘first’ H sapiens had parents and grandparents, who wouldn’t have noticed any difference between junior and themselves, so when does a new species actually begin?

Leaving that thorny problem, I’ll turn to another – when did the first nation begin? My uneducated conjecture is that it was an evolving concept, post-dating the evolution of human language, and we have little idea about when that process was completed, at least to the point where we could conceptualise and communicate such ideas. Modern nations, with boundaries, checkpoints, passports and state paraphernalia, are of course ultra-new, with some fresh ones popping up in my lifetime, but I’ve heard Australian Aboriginal language groups described as nations, with the first of these H sapiens arriving here around 65,000 years ago, according to the National Museum of Australia. Of course they wouldn’t have arrived here as nations, however defined, so when did they become such?  Bill Gammage, in The biggest estate on earth: how Aborigines made Australia, makes this point at the outset:

Hundreds of pages try to define Aboriginal social units (tribe, horde, clan, mob, language group, family, kin) without achieving clarity or consensus.

So is this a silly question? Surely not, since the term ‘First Nations’ has gained currency in recent decades. Rather bizarrely, the Wikipedia article on First Nations focuses solely on the early inhabitants of what is now Canada. This is presumably because these people are recognised as such by the Canadian government, at least for statistical reasons. In any case, these early people of North America, Australia and elsewhere mostly didn’t use writing, and their doubtless various self-references might be translated by us, at their bidding, as nations, but it’s clear that using such a term adds a certain gloss borrowed from modern lingo. Gammage does the same thing, perhaps justifiably, in referring to Aboriginal Australia as an estate, a term which I tend to associate with snotty landowners and gated communities. However, it also puts the focus on land, rather than people. 

We’ve come to associate nationhood with progress, civilisation and sophistication. No wonder the Kurds, the Basques and other cultural-linguistic groups are striving for it, and in particular for land on which to fix these qualities. The progression appears to go from group – as with chimps, bonobos and no doubt early hominids – to tribe, to settlement, to a collection of settlements or villages, to a centralised, sort of inward-facing region of shared culture, flourishing up to a civilisation of sorts. So it starts, for us, with our common ancestry with our primate cousins. 

We know that chimps and gorillas separate into groups that control particular territories, but if these groups are too small or avoid interaction with other groups, inbreeding will become a problem. This problem, which confronts all social species, can be solved by male or female dispersal – that’s to say, by breeding or ready-to-breed young adults flitting from their natal group to a neighbouring one. But moving to a new, unfamiliar neighbourhood might be as fraught, or more so, for non-human species as it is for us. According to an article published by the Royal Society in 2017, when there are limited opportunities for dispersal, many species appear to have a behavioural avoidance pattern to prevent inbreeding. For example, closely related elephants avoid mating altogether. In other species, they manage to mate without producing offspring, or produce healthy offspring even where the chances of inbreeding would seem to be high. 

We often make jokes about human inbreeding, especially with island populations (Tasmanians are sometimes targeted), but there are real issues with inward, ultra-nationalist thinking, which can lead to a kind of cultural inbreeding. This can even transcend nations, as with the touting of ‘Asian values’. Considering that millions of Asians have paired up with non-Asians, this might pose a problem for the offspring, if such notions were taken seriously.

Anyway, my own view of nations, for what it’s worth, is that that they’ve become a useful mechanism for divvying up land into states. Land has been an essential feature of human culture – this land is my land, this land is your land, this land is made for you and me. The obsession humans have with the myth of land ownership is something I’ve often found rather comical. I won’t go into the shenanigans around Antarctica, but I’ll relate a couple of illustrative anecdotes.

In my boisterous youth I accompanied a couple of housemates in visiting a nearby tennis court, which I’d previously noticed was surrounded by the usual high, open-wire fencing, but fronted by an unlocked gate. On the far side of the court were the vast sporting fields of St Peter’s College, one of the most exclusive private schools in the city, and beyond that, the imposing buildings of that august institution. I’d persuaded my housemates to take our racquets over for a fun hit out, though there was no net, and we only had two racquets between three. So we’d been at it for about 15 minutes when I spotted a figure marching towards us across the sward. As he closed in, I took note of the tweed jacket, the flapping flag of his woollen scarf, the swept-back, neatly combed blonde hair. I won’t try to mimic his accent or recall his exact words – distance lends a certain enchantment to the view – but there was no forgetting his sense of complete outrage. ‘Excuse me boys, but you must realise that this is PRIVATE PROPERTY!’ Those last two words are the only ones I’m certain of. 

I spent the next few weeks daydreaming of hoisting this gentleman by his own petard, but also reflecting on the quasi-religious power of landed property. It was exactly as if we’d abused, or worse, denied, someone’s god.  

Another incident was much more recent. An Aboriginal woman complained to me on the street that I – meaning we ‘whites’ – were on her land. I responded to her, perhaps in a frustrated tone, that land was land, it belonged to itself. This wasn’t particularly articulate, but she didn’t have any response. I suppose what I meant was that the Earth’s land, ever changing, shifting and subducting, had been around for billions of years, and for most of human existence we thought no more of land ownership than did the animals we hunted. How things have changed. 

Of course, nationalism is not going away any time soon, and I’m prepared to make my peace with it. States have their obvious uses, in binding a smaller proportion of the human population together via laws, economic co-operation and political policies. The Einsteinian dream of a world government is unworkable, and the United Nations still needs a lot of work, though it has been beneficial on balance, especially via its ancillary organisations. The problem of course is ultranationalism, in both its outward expansionist form, and its inward-facing exclusivity and xenophobia. Diversity, or variety, is obviously a good thing, whether in diet, industry, arts or genetics. My own modest experience in teaching students from scores of nations tells me that Homo sapiens, like Pan paniscus, are one people, with similar interests, in laughing, loving, wondering and striving for more. Our strivings and problems are much more global than national – a veritable internet of interests. I hope that this realisation is growing.  

References

https://aiatsis.gov.au/explore/map-indigenous-australia

https://en.wikipedia.org/wiki/First_Nations

https://royalsocietypublishing.org/doi/full/10.1098/rsos.160422

Bill Gammage, The biggest estate on Earth: how Aborigines made Australia, 2012.

Written by stewart henderson

April 22, 2021 at 7:57 pm

a bonobo world? 10 – the clothed ape

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Michel de Montaigne, aka Monty, endlessly honest, curious, humane and inspiring – to whom I dedicate my work, such as it is

I’ve observed that some humans don’t like being reminded that they are apes. They become scornful and dismissive, even while admitting that this might be so. I presume they consider it irrelevant. We’ve fallen far from the monkey puzzle tree after all. 

Of course we’ve built universities and particle accelerators and space stations, and ribbonworks of roads and rails connecting city to blazing city, but on sports fields we inflate ourselves and bump chests and chew cud and suck on straws and huddle together like a few other primates I know. So I often like to undress people, so to speak, in pubs and restaurants and classrooms and city streets, picturing them naked and never-shaven, with wobbly and dangly bits, flabby or skeletal, greying or balding, or pre-pubescently hairless, exposed, vulnerable, yet still humanly savvy. 

Michel de Montaigne wrote an essay, On the custom of wearing clothes, which I was keen to read in my twenties, both as a fanboy of Monty and as someone who’d long wondered about this custom myself. As children we come at some stage to the liberating realisation that we can question everything in the great sanctuary of our heads, where nobody else can trespass. At least, this happened to me. So I enjoyed this question – why do we wear clothes? And of course, I rehearsed the typical adult answer. We wear them for warmth, comfort and protection. But on a warm day, on the front lawn where we always run barefoot anyway? Or indoors, where there were no thistles, three corner jacks or rusty nails? And I knew that these were mostly bogus reasons, that there was a tabu about exposing ourselves – ‘Quick, we’re having visitors, go to your room and make yourself decent’. To be naked, or even half-naked, was indecent. Why? Of course as I grew older I realised it had much, perhaps everything, to do with sex. Sex was naughty, diabolically naughty, I knew that even before I knew what it was. It certainly involved the private parts, for decency was all about hiding those parts. Wearing a swimsuit was fine, at the beach and other appropriate places, and girls could wear bikinis, even though they actually accentuated the parts that we weren’t supposed to think about, but revealing or displaying those parts in public was verboten as verboten could be. 

And so I learned that sex was private, and perhaps rare.

But what if it wasn’t? What if people walked around naked in public, and had sex in public too? Presumably, that would be the end of civilisation. We would become like animals. But then, we are animals.

I really felt that I’d hit upon something profound, if perhaps a bit too obvious to be really profound. Could it be that the whole of civilisation depended on us wearing clothes, or at least covering up our supposedly naughty bits? And yet it was about more than just the naughty bits. Teachers didn’t teach us in their underwear after all. But could it be that adults wore full, formal outfits to teach classes or to work in offices or department stores, to disguise the fact that they were really just hiding their naughty bits? I mean, were those bits really so dangerously naughty? Bonobos seem not to think so.

Montaigne’s clothes essay, though as fascinating as any other of his other essays, is more titillating in its title than its contents (I’m easily titillated), which are mostly about weather conditions, class, and the best kits for warfare. A lot of modern essays on the topic, however, fare no better in addressing the clothing-and-sex issue. Of course it’s true that clothing would’ve been protective against bugs as well as animal bites – attacking and scavenging animals tend to go for the dangly bits – and that over time clothing would have had important decorative purposes, associated with in-group hierarchy as well as raising humans in their own eyes above their ape and animal nature. We’ve been doing this for at least 100,000 years. 

So human clothing has become habitual and near-universal over time. It’s embarrassing to be different, not only in going naked – which is also illegal, and the term indecent exposure is more revealing than anything that’s exposed – but in wearing the wrong outfit. Clothing has become extremely complex in that regard. I’ve lived long enough to observe my slight elders from the early seventies, with fabulous flowing locks and dazzlingly vibrant embroidered shirts, scarves and flares, gradually transforming into besuited computer techies and company directors, with children kitted out in Edwardian beards and long-suits, which somehow lack the sparkle of sexual spontaneity. 

And yet, we did undergo a sexual revolution, allegedly, which coincided with second-wave feminism, if I’m not mistaken. Widely available contraception helped, presumably, to allow women as much or little philandering as males. All-female sex parties have become fashionable, as have orgy-style sex parties with male strippers and female perps, victims and happy-clapping onlookers. But these are very much niche scenes, somewhat ritualised and behind closed doors, nothing like the bonobo world of spontaneous, open, all-community based sexual healing that is but one characteristic of a caring and sharing environment. The closest I’ve seen to this bonobo world is observing young women out on the town in supportive gangs, arms linked, laughing and chatting, rosy and cuddling. Males form their own groups, loving or at least appreciating each other in their own noli me tangere way. Not quite so inspiring. 

The problem of returning to our naked original state is, of course, the problem of returning the omelette back to the state of the uncracked egg. It ain’t gonna happen, and it’s arguable that this is a good thing. But that won’t stop me dreaming about a bonobo world, unclothed or otherwise, and finding and encouraging instances of bonobo behaviour among humans anywhere. And also trying to identify and critique trends that militate (good word) against the bonobo lifestyle, such as extreme libertariansm, macho-thug political leaders, zero-sum nationalism and divisive religious zealotry. Altogether, with of course many notable exceptions, there are encouraging signs. We are family, after all.   

References

https://www.journals.uchicago.edu/doi/pdf/10.1086/210885

https://www.popsugar.com.au/love/What-Like-All-Female-Sex-Party-43589464

http://essays.quotidiana.org/montaigne/custom_of_wearing_clothes/

Written by stewart henderson

November 12, 2020 at 4:51 pm

why homo sapiens sapiens?

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Homo sapiens sapiens – really??

Canto: Here’s a question. On the first page of Thomas Crump’s A brief history of science, he mentions our species, Homo sapiens sapiens. I’ve occasionally seen this designation before, but usually we’re only singularly sapient. What gives? I’m not aware of any species called Homo sapiens insapiens or quasisapiens or semisapiens, yet I’m sure there’s a reason…

Jacinta: Well I suspect it’s not because we’re big-noting ourselves, but then again, it is a self-congratulatory moniker, but we deserve it…. don’t we? ‘Sapiens’ being Latin for ‘wise’ or ‘astute’, and we’re doubly so, en it? Anyway, I think it’s about palaeontological techno-lingo, and it’s possibly controversial. Like we’re not the only Homo sapiens species but we’re the only extant ones, and we’re leaving a space open for some earlier Homo sapiens species, either yet to be discovered or yet to be designated as such, instead of being designated as Homo sediba or naledi or whatever.

Canto: So the Australian Museum, which designates us simply as Homo sapiens, does make a distinction between archaic (from 300,000 years ago) and modern (from 160,000 years ago) Homo sapiens, but needless to say, there is controversy, due to the paucity of the record and the mix of archaic and modern features, especially with fossils dated to before 160,000 years ago, which some scientists give an entirely different name, Homo helmei. 

Jacinta: Sounds like the lumpers and splitters issue once again. According to the Bradford foundation, the Homo helmei name is based on one partial skull dating from about 260,000 years ago (aka the Florisbad skull), and claimed (perhaps not by many) to represent an intermediate species between H sapiens and H heidelbergensis. But I suspect some of these scientists want to get recognition for identifying a new species rather than admitting that early humans, like modern ones, came in many shapes and sizes. 

Canto: Well here’s more from the Australian Museum:

Homo sapiens sapiens is the name given to our species if we are considered a sub-species of a larger group. This name is used by those that describe the specimen from Herto, Ethiopia as Homo sapiens idàltu or by those who believed that modern humans and the Neanderthals were members of the same species. (The Neanderthals were called Homo sapiens neanderthalensis in this scheme).

Jacinta: Interesting use of the past tense there. I note that the Australian Museum appears to state unequivocally that modern H sapiens is directly descended from H heidelbergensis. I also note that the Florisbad skull is measured as having a brain capacity larger than the average modern human, but I can’t see how much can be made of that. It’s no doubt still within the range. As for H sapiens idàltu, there’s disagreement, of course. If these 160,000 year-old Ethiopian fossil remains – which include three well-preserved crania, the best of which is of an adult male with again a cranial capacity on the large side – are accepted as a H sapiens sub-species, then this is said to justify the H sapiens sapiens subspecies nomenclature for the rest of us. 

Canto: That’s a partial explanation, but I still think the double sapiens moniker has a hubristic odour to it. Assuming H sapiens idaltu to be a genuine subspecies (such luminaries as the physical anthropologist Chris Stringer disagree), who’s to say it was less sapient than the line that led to us? Just because it didn’t survive? 

Jacinta: Well, that’s the dilemma – if you accept than there are other subspecies, then I suppose you have to accept a triple-barrelled name for each one. The third name – well, we can’t really choose a locality, because we’re everywhere. Or a skill, because we have too many. The name idaltu, by the way, comes from the Afar language around Ethiopia, and means ‘elder’ or ‘first-born’, which seems to suggest that this subspecies was ancestral to ours. In any case, you could argue that since our species basically controls the Earth, as mistresses of all we survey, the double sapiens title is well-earned. At least until we get zapped off our pedestal by multiply sapient aliens. 

Canto: Yeah, well, one sapiens is enough for me, and I’m sticking with that. 

 

References 

https://australian.museum/learn/science/human-evolution/homo-sapiens-modern-humans/#:~:text=Homo%20sapiens%20sapiens%20is%20the,members%20of%20the%20same%20species.

https://en.wikipedia.org/wiki/Florisbad_Skull

http://www.bradshawfoundation.com/origins/homo_helmei.php

https://en.wikipedia.org/wiki/Homo_sapiens_idaltu

Written by stewart henderson

September 27, 2020 at 6:36 pm

Human ancestry 2 – a meander through a couple of million years’ time and a world of space

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Man is descended from a hairy, tailed quadruped, probably arboreal in its habits.

Charles Darwin

Homo neanderthalensis, with a very bad toothache

 

So in this second post I’ll take a little look at Paranthropus and then try to make sense of the move from Australopithecus whateva to Homo whateva, and so on….

There’s a lovely vid about Paranthropus here, which I’ll take much of the following from. There are three known species, P aethiopicus (about 2.7 to 2.3 mya), P boisei (2.3 to 1.4 mya), both only found so far in eastern Africa, and P robustus (2 to 1.2 mya), in southern Africa. They’re all robust species, as opposed to the gracile species A africanus. They have large cheekbones, jaws and teeth, and a prominent sagittal crest across the top of the cranium, a feature shared by gorillas and orang-utangs, and which evolved to attach strong chewing muscles down to the jaw. Apart from these robust characteristics, they shared many features with australopithecines, and have even been defined as robust australopithecines by some. It’s always difficult to split up (or lump together) specimens when only small fragments are found, so there’s a hunt on for more, and bigger, bits and pieces. From what they’ve got, though, it’s estimated that they had a cranial capacity of 475-545 cc, not much more than the average chimp, with a height of about 156cm (just over 5 feet) and a weight of 40-50kg. Smallish perhaps, but I’d be willing to bet they had a pretty impressive muscle to fat ratio. They also appear to have been sexually dimorphic to a greater degree than humans, suggestive of dominant males fighting over females, as in the case of gorillas. There’s also some evidence that the females lacked or had a less prominent sagittal crest. 

How are the Paranthropus species related to modern humans? Surprise surprise, we don’t know, and the pathways to and between the various types of Homo just get more complicated. They may simply have died out, as the more recent Neanderthals did. Researchers desperately await more finds, and more techniques for connecting the dots. 

So, leaving Paranthropus behind, it’s clear from my last post on the subject that tracing the path from our common ancestor with bonobos (my fave ape) has been a fraught process of speculation and disputation, but of course we have no choice but to keep on trying to trace that path. So, what’s the most recently-lived species of Australopithecus, and the most ancient of the Homo species, as far as we know? 

The species A africanus and A sediba seem currently to be in competition to be the immediate ancestor to Homo habilis along the pathway to H sapiens, though there may have been an intermediate, as yet undiscovered, species.

A africanus is known from four sites, all in South Africa, but dating the specimens has been difficult and controversial. The first discovery, the Taung child (1925) is still not clearly dated, and claims for it suffered at the time of its discovery, and for decades afterwards, due to the Piltdown hoax, which I won’t go into here. However, in the mid 1930s the first adult australopithecine was found, and eventually given the A africanus moniker. Evidence of bipedality in this and another adult female, found in 1947, together with evidence of a cranial capacity of about 485 cc for both, was striking evidence that bipedality long preceded brain growth (it has since been mooted as a result of reduced forestation and increased savannah-like environments through climate change, though bipedal traits seem to have existed even before this). A lack of facial projection in these specimens was suggestive of advancement towards modern humanity. And just by the bye, evidence of tool-making among hominins now goes back to 3.4 mya, associated with the A afarensis species. A fourth specimen, ‘Little Foot’, dated to around 3.7 mya, was found in the nineties, but there’s debate about whether it belongs to A africanus or a ‘new’ species, A prometheus (actually suggested by Raymond Dart decades ago). There’s an interesting piece on this here.

I wouldn’t want to be quoted on this, but it seems that the A africanus fossil of a skull now known as ‘Mrs. Ples’ is the most recent A africanus fossil ever found, dated to about 2mya. But what about A sediba? This is the most recently discovered australopithecene, mostly associated with Lee Berger (and his young son), who discovered the first bones in 2008, in South Africa. It has been argued, by its discoverers, to be the most likely transitional species between A africanus and either Homo habilis or H erectus (and it should be noted that many consider H (or A) habilis to be an australopithecine, its placement as Homo being largely based on the use of flaked stone tools, at a time when tool use by australopithecines wasn’t known).

So I think I’ll skip this controversy for now, as I want to get to the more recent radiation of Homo species. Having said that, immediately I start looking at the earliest forms given the Homo moniker, such as H habilis, H erectus and H ergaster, I encounter vast uncertainty and controversy, not to mention my own ignorance. I’ve already discussed H habilis; H ergaster (1.9 to 1.4 mya), according to Wikipedia, ‘is now mostly considered either an early form, or an African variety, of H erectus‘. Oh dear, I thought H erectus was African!

In fact, the first fossils identified with H erectus were found in Eurasian Georgia and in China, but the species may have back-migrated to Africa. Or maybe not. I’m on the verge of giving up here, but I’ll extricate myself from the mess by listing and briefly discussing the various forms of Homo that have been postulated. These aren’t necessarily in chronological order.

  1. H habilis (approx 2.1-1.5mya) – short but with longer arms compared to modern humans, with a cranial capacity of around 700 cc. Used stone tools. Relatively robust, compared to H ergaster. Contested classification. Probably co-existed with H erectus. Only found in Africa.
  2. H ergaster (approx 1.9-1.4mya) – I’ve used the Wikipedia existence range here, but the Australian museum suggests that arguments about existing classification of specimens may extend that range up to 700,000 ya. They also point out that some don’t accept this classification at all, preferring H erectus. They were relatively hairless and more closely resembled modern humans than earlier types. Possible specimens found in modern Kenya, Ethiopia, South Africa, and most notably in Georgia (Eurasia), which suggests first emergence of early humans from Africa occurred about 1.7mya. Cranial capacity, about 860cc .
  3. H erectus (approx 1.8mya- 100,000ya?) – first found in Java, other specimens found in Indonesia, China and Africa. Short and stocky with heavy brow ridges. Sometimes hard to separate from H ergaster, especially the African specimens. H erectus is now more widely believed to be a side-branch, and H ergaster our more direct, if more ancient, ancestor. Cranial capacity about 1050cc.
  4. H rudolfensis (approx 2.4mya- 1.8mya) – specimens found in modern Malawi and Kenya. A contested classification, could be lumped in with H habilis. There is always a difficulty when dealing with limited specimens, which might be atypical, juvenile or of unknown gender. Anyway, estimated cranial capacity, about 750cc. Size and shape insufficiently known.
  5. H heidelbergensis (c700,000-300,000 ya) – evolved in Africa, but in Europe by 500,000 ya (African fossils are mostly older). Lived and worked in co-operative groups, using a variety of tools. Specimens found in England, France and Spain as well as in the region of Heidelberg, Germany. Possibly as far east as northern India. Also in Zambia and South Africa. Physically tall, up to 180 cms, suggesting descent from H ergaster. Brain capacity approx 1250cc.
  6. H neanderthalensis (?800,000-40,000 ya) – some have argued that they were around as recently as 28,000 years ago. The first fossil was found in the 1820s, and was the first fossil of any extinct hominin ever found. Their cranial capacity, at 1500cc, is larger than that of H sapiens, not surprisingly due to their larger overall build (shorter but much more solid). No specimens found as yet in Africa, but a large number of finds throughout Europe and the Middle East (and possibly in China) allow us to build a clearer picture of Neanderthals than any other extinct hominin. They used a variety of tools, which they may have obtained through trade with modern humans. They wore animal hides and used fire for warmth, cooking and protection. Physically they were thickset, with heavy brow ridges and a relatively receding forehead, a forward-projecting face, a large, broad nose, and strong neck muscles. It’s now known, of course, that they interbred to some degree with modern humans, but it’s also likely that they competed with them for scarce resources, especially during ice ages. Though we don’t now consider them to be ‘nasty, brutish and short’ it may well be that the greater resourcefulness of H sapiens hastened their demise.
  7. H rhodesiensis (c800,000-120,000 ya) – now generally seen as an African subspecies of H heidelbergensis, with specimens found in Rhodesia/Zambia, Ethiopia and Tanzania.
  8. H cepranensis (c900,000-800,000 ya) – based on one fossil skull cap, or calvaria, unearthed near Ceprano, Italy in 1994. Others are for H heidelbergensis. The dating is also highly contested, with some arguing for around 450,000 ya. There’s probably quite a few more of this sort – but every new find is exciting.
  9. H denisova (? – 15,000 ya) – This isn’t an agreed taxonomic title, but the Denisovan finds are certainly exciting, with mitochondrial DNA being recovered from the first find (in a Siberian cave), the finger-bone of a juvenile female (how do they know that??). Other specimens have been found in the same cave, and another has been found in Tibet. There’s not enough material for us to picture this species, but the DNA tells us that they interbred with Neanderthals, and to a lesser degree with Melanesians, Papuans and Aboriginal Australians.
  10. H floresiensis (c190,000-50,000 ya) – found only on the Indonesian island of Flores. Another exciting, and puzzling, recent find. Could they have been killed off by those passing though on their way to Australia? Researchers are still hoping to recover mitochondrial DNA from the most recent specimens. Physically, these were unique humans with a very small stature and a cranial capacity of 380cc (chimp size), though with an enlarged Broadman area 10, which is associated with complex cognitive abilities. Other skull features, though, suggest a primitiveness going back more to H erectus. Tools found at the site have raised controversy. Do they belong to H floresiensis? They don’t easily equate with such a small brain. There is no precedent. Much still to be learned.

So I’ve raised far more questions for myself than I’ve answered. Hope to come back to this topic in future, with a focus on bipedality, climate effects, the beginnings of ‘culture’, and migration, among other things.

References

https://australianmuseum.net.au/learn/science/human-evolution/ (a great site, with links to details on particular species)

Paranthropus evolution (video), by Stefan Milo, 2019

https://en.wikipedia.org/wiki/Australopithecus

https://en.wikipedia.org/wiki/Australopithecus_africanus

https://en.wikipedia.org/wiki/Australopithecus_sediba

https://en.wikipedia.org/wiki/Homo_ergaster

http://humanorigins.si.edu/evidence/human-fossils/species/homo-habilis

Written by stewart henderson

October 30, 2019 at 9:59 pm