Posts Tagged ‘Ethiopia’

1.1 How it started

PART ONE: HOW HUMANS BECAME HUMANS FROM APES

1.1 how it started

Ten million years ago the climate became cooler and drier. Miocene jungles, that until then reached halfway into Eurasia, gradually retreated in the direction of the equator, being replaced by open savannahs. Five million years ago the jungle where our earliest ancestors lived in Northeast Africa, especially east of the Great Rift[1], started to undergo this change. It is here that our story begins.

Humanosophic version of the human family tree

Our earliest ancestors were hominid apes. Frans de Waal (Bonobo 1997) says that, if we want an image of our earliest ancestors, we should look at the bonobos. They are the only kind of chimpanzee whose environment never changed. A species will only change when its environment changes. The environment of our earliest ancestors[2] changed totally, so our early ancestors changed totally. The environment of the chimpanzee ancestors changed much later and partially, so the chimpanzees changed partially.
Here, we will name our earliest ancestors ‘our[3] ancestor-bonobos(ANBOs).

It took millions of years for their jungle to turn into a savannah. Our ANBOs never were aware of this change; for them the world was in every phase like it always was. So the adaptations to the new conditions passed unnoticed. But for our story these adaptations are crucial. Not the physical adjustments so much, but especially the social and mental, in short the cultural evolution.

The savannah is a diverse environment consisting of open woodlands, mixed with impenetrable shrubs and grasslands accommodating herds of many kinds of grass eaters.

Our ANBOs lived in the woodlands, where like many present-day apes, they spent the nights in nests high in the trees. But these woodlands along the shores of rivers and lakes didn’t contain the fruit trees their ancestors used for sustenance. For food, our ANBOs had to roam the open grasslands: a dangerous area because of the big cats that preyed on the grass eaters. The saber-toothed tigers were specialists in preying on pachyderms: rhinoceroses, hippopotamuses and (ancestors of the) elephants.

I want to emphasize that the Miocene (22 – 5 million years ago) savannah was characterized by megafauna (large animals) and was much more dangerous than the current Serengeti. Lions, saber-toothed tigers and giant hyenas were formidable predators. Though the little ANBOs were much stronger than we are now, they needed special armament to roam the grasslands safely. This was: throwing stones to keep the predators on distance.

This can be illustrated by the behavior of apes today. Jane Goodall tells the story of the adult chimp male ‘Mister Worzle’. The bananas she left for the chimpanzees in order to study their behavior in the neighborhood, also allured baboons (large and brave monkeys) that frightened some female chimpanzees. But Mister Worzle did not give a centimeter of ground and threw anything he could grasp: grass, branches, once a bunch of bananas (baboons happy!). Soon he discovered that stones worked better and that bigger stones worked even better. And he began to gather them on a heap.

Our ANBOs needed to become ‘professional’ stone throwers. They could not take a step on the open grasslands in safety without their armament of stones. Who did throw men or women?
Women carried babies and had to gather food stuff. Men with their stones made sure that the group went safely around over the open grasslands. Division of tasks from the beginning .
One stone was not enough to ensure their safety; the men needed a handful of stones. But how you can as an ape carry a handful of stones?

skull sabre cat

 

Sabre cats – we already mentioned them – were specialists in predating fat-skins like elephant-like and rhinoceroses. They stalked such a meat fort and after a fierce sprint they turned open its soft underbelly (these cats could open their mouth unusually wide, the sabres laying in the extension of the skull (see photo).

Sabre toothed tigers ate only the entrails of their kill. The rest of the carcass was left to other animals. As soon as vultures started circling around from their high vantage point, lions and hyenas knew that a meal was coming. Lions were first, then the hyenas and the vultures ate the left-overs. Because of the steady supply of carcasses by the sabers the basically inedible, hairy or leathery skins and the skeletons stayed there. The ANBOs beat the bones for the marrow with their stones and used the hides to carry things[4]; with their long experience in braiding and wattling their sleep nests, tying these hides was easy.

But how will apes carry bags filled with stones? How do bonobos and chimps carry heavy things? They use their hands, so they must walk upright on their feet. Our ANBOs needed to become bipeds: without carrying some stones for armament, it would not be safe for them to venture into the open grasslands.[5] In tens of hundreds of thousands of years our ANBOs, having no other choice, turned into bipeds with longer and stronger legs, special pelvic and buttock muscles, special midriff and blood circulation[6]. At least they made a good start developing these properties, good enough for foraging on the savannah. They kept using their hands and feet for climbing: it was not safe to sleep on the floor, so they still needed them to make sleeping platforms high in the trees of the woodland.

Females had to carry their babies and gather food for themselves and the rest of the troupe, so they couldn’t carry and throw stones. Males couldn’t gather food: they had to offer protection, because hungry predators were always watchful for moments of unalertness. So our ANBOs cultivated a division of labor from the very beginning. Women and children gathered food: grass seeds, tubers and roots which they dug up with digging sticks[7], larvae and insects, eggs and small animals. The adult men did nothing but provide safety. The groups who practiced those behaviors most effectively, flourished (by keeping more young alive) and soon outnumbered the groups that were clumsier at these things. Through hundreds of generations, the population exhibiting these behaviors, were the fittest and survived.

The same mechanism applies to group harmony. Because of the big cats and the giant hyenas, the open savanna was a dangerous environment for apes and forced them to maintain strict group harmony. That was not a big problem at all: bonobos live in female-dominated groups characterized by group harmony, and solve tensions with sex.

Dentitions. Left: chimpanzee. Middle: australopith. Right: human

Clearly, our ANBOs probably ‘professionalized’ and optimized this behavior. The dentition of male bonobos still shows large canine teeth that can be used as weapons in sexual competition – although, chimpanzee canines are larger. Fossil australopith dentition shows reduced size of the canines: partially as a result of the need for grinding hard food like grass seeds, but also as a result of reduced male competition.[8] That our ANBOs solved all tensions with sex, is clear because while the size of the canines was reduced, the penises were enlarged! Of course the ‘attractive’ red vaginas of bonobo females and the heavy scrotums of bonobo males were not practical for bipeds, so those were reduced in size too. Every time the women were in estrus, this intensified male competition and group tensions. Therefore, the women’s periods became less noticeable as well. All these reductions were compensated with nice breasts and buttocks for the women, and continuous sexual willingness: mechanisms for reducing tensions and fostering group harmony.

Didn’t the men hunt? No way. Australopith bipedal locomotion was not fast enough to compete in hunting with the savannah predators. Nevertheless, besides birds eggs, insects and larvae there was yet another protein source for them on the savannah: hides.

Afbeeldingsresultaat voor h. erectus slacht olifant Savannah today: more open space than in the ‘cradle of humanity’ which we suspect was in the Afar region of Ethiopia of 5 mya: woodland with less open spaces; but we can imagine an AP-group walking one after another between the grazers on their foraging trip. They were no danger to the grazers; as long as those kept quietly grazing, this meant for the ANBOs that it was safe for them as well, and they walked calmly, with their free hand occasionally stripping off grass seeds to chew them; in the meantime the women were searching for the edible tubers, recognizable by their leaves; and then the group had to stop for some time while the men watched with their stones.

As already mentioned, the hides all over the place, left behind as less edible by the other meat-eaters of the savannah, provided a new niche for the handy ANBOs. There was protein-rich tissue left on the hides to pick and scrape them with the sharp edges of bones, shells and stones. And when a hide was scraped totally clean, it made a perfect bag to carry things such as stones, or it made a blanket to use in cold nights, a screen against sun, wind, or rain. These multipurpose hides were the ANBOs’ first and only property. The paleos lack attention for the importance of the hides in the technical development of our ancestors, an omission that is understandable because hides are not preserved at archaeological sites (just like digging sticks and similar soft-material tools).
But philosophers are allowed to speculate more freely for the benefit of our Great Story, to immediately correct it as soon as a scientific evidence disproves a speculation[9].

Actually, this use of hides marked the beginning of ‘the stone age’: the beginning of the use of stone flakes for processing hides.

Processing hides, soon slaughter of found carcasses, later slaughter of the prey carcasses of the men: until recent HG-times it is females work. Turning stones into useful tools as scrapers and knives is females work. Our primatologists tell us that male chimpanzees use stones only for impressing behavior but female chimps use them for cracking hard nuts. Stone technology was a female invention, even before the birth of mankind.

All these environmental changes and physical adaptations developed unnoticed by our ANBOs. Just like all apes 7 million years ago, they made their daily foraging routes in a vast foraging territory. In the course of two million years, ever more open grasslands became part of their territory and daily route. All necessary adaptations developed during this time. By 5 million years ago, the hominins (australopiths, bipedal apes), including our future ANBOs, were experienced woodland/savannah foragers.

What remained rather unchanged was their way of life. They would leave their woodland nests early in the morning, wander along a route they knew perfectly, gathering food along the way, and finally arrive at the next woodland where they would share the gathered food and then make their nests high in the trees. The only part of the routine that changed, was that instead of eating their food while ranging on the grass lands, they carried most of the gathered food (tubers, grass seeds, larvae, eggs, and so on) to their overnight place in some wood, to be distributed equally among all group members. This was necessary because the men had less opportunity to get food enough during the foraging: their vigilance could not be allowed to weaken for a moment because of the permanent threat of the hungry predators.
After dinner and before the evening twilight, everybody had to climb in a tree and braid her or his nest.

Like their ancestors they lived in groups. Not too large: too much mouths to feed; not too small because there were enough men needed for the protection against predators. This asks for a number of around 25 individuals. But the composition of a group constantly changed and there was also constant exchange with nearby groups.
This meant that harmony within the groups as well as between the groups was conducive to the flourishing of the population. Therefore natural selection selected harmonious behavior as ‘good’. Our ancestors became ‘good natured’[10].

During 99.5 % of the long time span our species existed, our ancestors were first gatherer-scavengers and later gatherer-hunters.

  1. Paleo Tim White points to the Middle Awash (Ethiopia) as ‘the window on human past’
  2. Assuming that they lived in the forest of today’s Ethiopia, now desert but in the words of paleo Tim White at the time ‘a lush environment’ with lakes and rivers.
  3. ‘our’ because bonobos and chimps have their ANBOs too
  4. See also Nancy Tanner and Adrienne Zihlman in Mothers and Daughters of Invention (1995).
  5. Other speculations about the origins of bipedalism, such as: better sight or less body parts exposed to the sun, lack the answer on the obvious question: why then didn’t the other savanna-dwellers like zebras or baboons become bipeds?
  6. For the physical adaptations: Elaine Morgan Scars of evolution . London, 1990
  7. Today’s woodland chimpanzee females are observed digging up tubers with self-made digging sticks!
  8. Mind also the reduction of the chewing apparatus from ape to human.
  9. After all, we did it thousands of years with Great Stories that were entirely dreamed up.
  10. For Frans de Waal even chimpanzees are Good Natured (1979)

9. The second big jump to humanity: fire.

We are not sure which fossil, if any, belongs to the population of animals that could name things. Brunet, head of the French group which found the 6-7 million year old hominid skull in Chad, is shown with the skull, saying: “It’s a lot of emotion to have in my hand the beginning of the human lineage…” But there is no label on the skull, and it is impossible to know if the skull in his hand is from an ancestor-bonobo, or from a prey of the ancestor-bonobos.

Around 2.5 million years ago, the ancestor-bonobos evolved into ancestor-australopiths. There is proof of their existence: not a skull, but stone tools.

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At 15 locations east and west of the Kada Gona river, Ethiopia, Sileshi Semaw and his team recovered more than 3000 surface and excavated artifacts, dated 2.6 –2.5 million years ago. [Journal of Archaeological Science (2000) 27, 1197-1214]

Makers of these well-flaked artifacts: Australopithecus garhi. Archaeological name of these earliest stone industry: Oldowan.

Other early Oldowan sites, older than 2 million years ago: Olduvai, Omo, Bouri, Lokalei.

All these 2.5 million years old artifacts were found together with animal bones, many of them with stone-tool cut-marks. A recent publication[1] about cut-marks on bones from the Dikika site in Ethiopia demonstrates that stone ‘knives’ for processing of bones of scavenged carcasses may have been used even earlier: 3,4 million years ago. So these artifacts are butchery tools: the cut-marks on the bones are the result of “hunting and/or aggressive scavenging of large ungulate carcasses”.

To me, these Kada Gona tools are the hallmark of the second big jump of our ancestors, as the consequence of the first jump: names for the things. It was the climate again that triggered the jump. For five million years, the climate had been stable without giving much reason for changing behavior. But then the Ice Ages, the periodical increase of ice caps on the poles and around the high mountains, began. Now there were cold periods (stadials, maxima) interspersed with warm periods (interstadials, minima). It started with a dramatic cooling and drying. Jungles receded to a narrow and interrupted belt around the equator; savannahs turned into deserts. There were ever less trees to sleep in, ever more natural fires.

The ancestor-australopiths knew some attractive qualities of fire, and they were not the only animals who were lured by the far clouds of a natural fire. Vultures and other carrion eaters and even antelopes approached carefully, enticed by carrion and salty ashes. The females that could name things knew that some tubers and other plants, normally not edible, were edible after the work of the fire.

Why women again? Women have to feed their children. In everything they do, they are motivated by the need for more and better food for their children. Perhaps this time it was an old and experienced woman, a grandmother who had the courage to take a glowing branch of an smoldering natural fire. Trembling with fear, she took it to a safe place, fed it with dry grass and wood and breathed in new life: fire.

Terrified, of course, the other ancestor-australopiths observed from a distance, screaming in fear at what the grandma did. She held a tuber on her digging stick in the flames. When she thought the tuber was done, she tasted it, went with the tuber to her granddaughter. Granddaughter would remember this moment ever in her life.

Too nice, this ‘just-so-story’? Then consider this: gorillas have been observed sitting near a smoldering fire in nights when the temperature on the savannah approached the freezing point. But no ape is known to ‘feed’ the extinguishing fire with combustible material.

But our ancestor-australopiths did: because they already had a name for fire, they gradually lost their instinctive fear of the fire and got a feeling of power over it. After this, of course it took many generations before they had developed the technique to carry the fire from one campsite to the other, as live charcoal in a bovine’s horn or in some similar way.[2]


[1] Nature, 12 Aug.’10
[2] If you don’t believe that such an early ‘taming’ of fire can be postulated, ask Ralph Rowlett of the University of Missouri-Columbia in Missouri.

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Used abbreviations

GHs: gatherers/hunters (the phase from 2 million years ago to 10.000 years ago)

AGRs: agriculturers (the phase from 10.000 years ago till now)

NT(s)Neanderthal people

MSA(s): Middle Stone Age people (African NTs)

AMH(s): Anatomical Modern Humans (H sapiens people), like we are

(m)ya: (million) years ago

ANBOs: Ancestor Bonobos (ape-men), our earliest human ancestors

Paleos: all scientists that are important for our story.

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