Tag Archives: Africa

Blombos

75 thousand years ago

The period between the time Homo sapiens leaves Africa 120 thousand years ago, and the time when H. sapiens spreads far and wide through Eurasia, replacing Neanderthals and others, 45 thousand years ago, sees episodes of increasing cultural complexity in Africa. One of these occurs at Blombos cave, at the southern tip of South Africa. There, over tens of thousands of years, people make a cultural great leap forward.
blombos2
75 thousand years ago, we find that they produce finely crafted stone blades that are part of multi-part composite tools. They make shell ornaments.

blombos

And they etch ocher (a red stone useful as a dye, but not for tools).

Oddly though, this tradition doesn’t last. It’s over by 60 thousand years ago. It may be that people left as climate deteriorated. But Blombos cave is a reminder that cultural progress is not always a permanent thing. It looks like an early instance of Rise and Fall: a culture rises to new heights, and then falls back.

African geneses: Bushmen

271-257 thousand years ago

You’ve probably run into some version of the factoid that there is more genetic variation in Sub-Saharan Africa than in all the rest of the world. This assertion has to be handled with care. It doesn’t necessarily apply to genes that have been under strong diverging selection pressures on different continents. Consider skin pigmentation: there is not more variation inside Africa than outside it in skin color, or in genes for skin color. Obviously. Likewise for hair form. But it’s true for neutral genetic variation, which is most genetic variation.

The simplest way to account for the broad Africa/non-Africa distinction would be to assume a large homogenous founder population in Africa, with a smallish number of people leaving Africa and going through a genetic bottleneck, thereby reducing their genetic variation. But recently we’ve been learning that the African situation is more complicated. Specifically, there used to be a lot of genetic differentiation between different regions within Africa. Recent population movements have smoothed out some of that variation, but recent work on ancient DNA has been bringing this more variegated past to light.

A case in point: the latest data imply that the Bushmen of Southern Africa separated from other African populations (East African, West African) around 260,000 years ago (at least), long before the major Out Of Africa venture by modern humans. What’s more, the very latest data imply that the Bushmen have received outside genetic input pretty recently, in the last 1-2 thousand years. This admixture, 9-22% of the ancestry of modern Bushmen, is absent from a 2,000 year old skeleton from Ballito Bay, South Africa.

The intruding population were probably pastoralists whose livestock, and a fraction of their genes, ultimately derived from the Near East. Another fraction of their genes originated in the Sahel or East Africa. And they probably spoke a language in the Nilo-Saharan or Afro-Asiatic family. These language families pop up as a substrate in East Africa, although largely overlain by the later expansion of Bantu speakers.

One implication: Bushman groups like the !Kung have often been presented as models for our Pleistocene hunting and gathering ancestors. Yet the most recent findings imply that there has been substantial interaction, including gene flow, between Bushmen and non-hunter-gatherers for some time.

A relevant result from twentieth century anthropology: when Nancy Howell did her classic work on the demography of the Dobe !Kung Bushmen, she found that, when you look at female reproductive histories, the Dobe !Kung look like a growing population, but when you look at male reproductive histories, they look like a shrinking population. There’s no contradiction here: the women, but not the men, in the population were sometimes having children by outsiders, neighboring pastoralists. The pastoralists in question were Bantu, having arrived in the last few centuries, but the latest genetic data imply that something similar was going long before the Bantu showed up. Since it’s not clear what effect this subaltern sexual status might have had on Bushman social organization, the social life of historic Bushmen may not be a good model for hunter-gatherer life before agriculture.

Here’s the article on Ballito Bay Boy.

And a recent review article from Nature

African geneses

303 – 288 thousand years ago

Our picture of human evolution in Africa around 300 thousand years ago has changed dramatically in just the last few years.

brokenhillHere’s something we already knew. This skull was found at Broken Hill, Zambia, in 1921, He (yes, “he,” he’s probably male) is sometimes known as Rhodesian Man. He looks like he’s a step away from Homo erectus, but not quite Homo sapiens. He’s heavily built, with massive brow ridges. (He looks like he could pass the “pencil test” for erectus: you could rest a pencil on those ridges. Of course, seriously, this isn’t enough to define a species.)  But he’s got a flat face and relatively large brain. He could be significantly younger than 300,000 years ago.

jebel irhoudBut now Rhodesian Man is bracketed both geographically and evolutionarily by some new finds. From Jebel Irhoud, Morocco, around 315 thousand years ago, come these skulls, which are more unequivocally Homo sapiens. pushing the fossil record of our species back 100 thousand years. The skull is still archaic – elongated rather than globular like a modern human – but the face is now tucked under the skull, as it is with us. The brow ridges are not as pronounced as with Rhodesian man, although still heavy for modern Homo sapiens.

naledi.jpgAnd we now have dates for Homo naledi, from South Africa, of 335-236 thousand years ago. This recently discovered species had a tiny brain, and may have been adapted for climbing trees, but still makes it into genus Homo based on other features (teeth and jaws, lower skeleton). The initial guess from a lot of folks was that this was a very early member of our genus, somewhere around early Homo erectus or earlier. But instead, Homo naledi looks to have been around at the same time as early Homo sapiens.

In other words, Africa 300,000 years ago was home to an impressive variety of humans – archaic Homo sapiens in Morocco, near relations in Zambia, and barely-humans in South Africa.

Amplifier lakes

1.93-1.83 million years ago.

We’re now counting off past time at the rate of 100,000 years a day.

Paleontologists and paleoanthropologists are busy sorting out what was special about the climate and ecology of Africa, especially East Africa, that contributed to various phases of hominin evolution. (“Hominin” is the current label for everyone more closely related to us than to our closest living relatives, i.e. chimpanzees and bonobos. My spell checker wants me to change it to hominid, the old label.) For example, Elizabeth Vrba, a South African paleontologist, argued that about 2.5 million years ago East Africa experienced a “turnover pulse” that affected a number of species. As the climate shifted toward cooler weather, and grasslands expanded, there was a wave of extinction and speciation among antelopes and (arguably) hominins as well.

More recently, paleoanthropologists have argued that not just cooling or aridity per se, but climate variability played a major role in driving hominin evolution, with episodes of greater variability leading to various responses ­– extinction, habitat tracking, or greater behavioral flexibility – as suggested in the diagram below.

climate early homo potts

More specifically, it looks like there were particular times when lakes were flickering in and out of existence along the Eastern and Western arms of the East African Rift Valley. Between just under 3 million years ago and just under 1 million three episodes stand out: around 2.7-2.5 mya, 1.9-1.7 mya, and 1.1-0.9 mya. These happen at intervals of 800,000 years, and may be tied to very long cycles in the eccentricity of Earth’s orbit. Within each of these episodes, the Rift Valley was home to large numbers of “amplifier lakes.” These lakes formed briefly during short intervals of high precipitation, and then evaporated quickly, making for a rich (sometimes) but also a particularly challenging environment.

climate early homo maslin

Tellingly, it looks like these episodes were also associated with important events in hominin evolution. of 15 hominin species that evolved in this period, 12 appeared during these episodes.

This story, and much more, are set out in Lewis Dartnell’s very recent Origins: How Earth’s History Shaped Human History.

Tutsi and Hutu

October 1993 – January 1996

In just one hundred days in 1994, some 800,000 Rwandan Tutsi were murdered under the direction of the Rwandan government, with the participation of a large part of Rwanda’s Hutu majority population. This was genocide, the last major genocide of the twentieth century. However US diplomats were forbidden to use the word. Calling it genocide would have obliged the international community to intervene.

A few comments:

The internal violence in Rwanda was closely linked to external conflict. Next door to Rwanda is Burundi, with a similar demography – a Tutsi minority and a Hutu majority. But politics took a different course in the two countries. In Rwanda the Hutu took power when the country attained its independence in 1963, and the government directed massacres of Tutsi. Meanwhile, in independent Burundi, the Tutsi dominated. In 1972 100,000 Hutu were massacred there. The next year saw anti-Tutsi riots in Rwanda. The genocide in 1994 followed a seizure of power by Hutu extremists, who played on fears of a Tutsi takeover. French political scientist Jacques Semelin calls Rwanda and Burundi “ethnic false twins.” He notes similar “fratricidal duos” in the case of other twentieth century genocides – Serbia and Croatia, Nazi Germany and the Soviet Union, Ottoman Turkey and Czarist Russia. In each case, mass killing of ethnic minorities – of Croats, Jews, Armenians –  was tied, in the minds of the perpetrators at least, to life-and-death external threats.

The history of the Tutsi and the Hutu goes back a ways, although group boundaries were accentuated by Belgian colonial policy. Genetic and ethnohistoric evidence points to the Tutsi being a an offshoot of the great migration of Nilotic cattle-herders over the last millennium, while the Hutu derive ultimately from an even greater demic expansion, of the Bantu. The Tutsi came to speak the same language as the Hutu, and there has been some intermarriage between the two populations, but they are still physically fairly distinct from one another, with the Tutsi taller and thinner. These physical differences played into the development of ethnic animosity, an instance of “somatic prejudice.” A major theme of anti-Tutsi propaganda in the period leading up to the genocide is that Tutsi women were especially sexually alluring, but also wanton, dangerous, and emasculating. A few story titles, “Beautiful Tutsi Women as Bait into Servitude” and “The Death Trap of Tutsi Women’s Beauty,” make the point (as did a lot of visual pornography). In the Hutu Ten Commandments, a major piece of anti-Tutsi propaganda published in 1990, the first three commandments are concerned with resisting the allure of Tutsi women. Sexuality and ethnicity are the source of some of our most intense emotions; together they make an especially combustible combination.

The world at 1000 BCE

Here’s a quick look at the world around 1000 BCE

The world population is about 50 million.

The Bantu expansion is just beginning, from a homeland on the present Nigeria/Cameroon border. It will eventually cover most of Africa south of the equator. The expansion is sometimes told as a story of first farmers replacing hunter-gatherers. But, as with the Indo-European expansion, this now looks to be too simple. Other farmers and herders reached east Africa before the Bantu; traces of their languages survive as eastern Bantu substrates. So the Bantu had something extra – social organization? malaria resistance? – going for them.

Seafarers with roots in the Lapita culture have already reached Western Polynesian – Samoa and Tonga, previously uninhabited.

The Olmec are flourishing in Meso-America. A controversial find (the Cascajal block) suggests they are just taking up writing.

In China, the Mandate of Heaven has passed from the Shang Dynasty to the Zhou.

In the Near East and Eastern Mediterranean, the Late Bronze Age collapse has opened up space for smaller states. Tyre and other Phoenician city-states are sailing the Mediterranean. Phoenicians are using an alphabet that Greeks will eventually adapt. There might be other borrowings: Odysseus might originally have been Phoenician. At least that was the argument of the early twentieth century French diplomat and classicist Victor Bérard. He thought that Homer had folded an earlier Phoenician picaresque tale into his epic. James Joyce was very taken with this theory; Joyce’s Levantine Leopold Bloom owes something to Bérard’s Phoenician Odysseus.

Further south, Philistines and Israelites have been duking it out, with Israelites gaining the upper hand under David* (king from 1010 to 970 BCE). The Iron Age conventionally begins now, with the widespread use of iron – more abundant and cheaper than bronze.

On the steppe, horses have long been domesticated, but people are now learning to make effective use of cavalry – fighting in formation and firing volleys from horseback. This is the beginning of 2500 years in which the division between Steppe and Sown will be central to Eurasian history.

* Everybody knows that David killed Goliath (1 Samuel 17). However, according to 2 Samuel 21:19, Goliath was killed by Elhanan of Bethlehem. (Depending on which version of the Bible you use, the victim might be given as the brother of Goliath, but this is a later interpolation. It’s plain Goliath originally.) Probably the Elhanan story is the original one, and the whole David-and-Goliath story amounts to later resume-padding on the part of David at the expense of a subordinate. See The Historical David: The Real Life of an Invented Hero for this and other demonstrations of how we can recover likely truths from historical texts.

Blombos

75 thousand years ago

The period between the time Homo sapiens leaves Africa 120 thousand years ago, and the time when H. sapiens spreads far and wide through Eurasia, replacing Neanderthals and others, 45 thousand years ago, sees episodes of increasing cultural complexity in Africa. One of these occurs at Blombos cave, at the southern tip of South Africa. There, over tens of thousands of years, people make a cultural great leap forward.
blombos2
75 thousand years ago, we find that they produce finely crafted stone blades that are part of multi-part composite tools. They make shell ornaments.

blombos

And they etch ocher (a red stone useful as a dye, but not for tools).

Oddly though, this tradition doesn’t last. It’s over by 60 thousand years ago. It may be that people left as climate deteriorated. But Blombos cave is a reminder that cultural progress is not always a permanent thing. It looks like an early instance of Rise and Fall: a culture rises to new heights, and then falls back.