̽��ֱ�� of Cambridge - tool

Opinion: No giant leap for mankind: why we’ve been looking at human evolution in the wrong way

Anonymous — Tue, 14 Jun 2016 13:21:45 +0000

Understanding exactly how and why humans evolved is clearly one of the most important goals in science. But despite a significant amount of research to date, these questions have remained a bit of a mystery. Of course, there is no shortage of theories – it has even been suggested that humans are just visiting aliens. However, most of the credible models tend to take something that is unique to humans – such as language – and show how all the other bits of being human derive from that.

But focusing on one dramatic change as an evolutionary driver in this way may not be the best approach to understanding our past. ̽��ֱ��question was discussed in a series of papers in Philosophical Transactions of the Royal Society B.

Hunting is a good example, as it is often used to explain human evolution. We eat far more meat than other primates – most of them are in fact entirely vegetarian. It has therefore been argued that meat was the high quality resource that allowed humans to evolve large and complex brains.

What’s more, it takes communication, cooperation and technology (those stone tools came in handy) to acquire it, so hunting could also explain a number of other typically human traits. Eating large animals also could also taught humans to share, leading to social cohesion and interdependence. Hunting is just one of many models that have been proposed to explain human uniqueness and cultural complexity – language, fire, cooking and grandmothers, who enhanced human success by investing in their daughters children instead of having more themselves.

Vince Smith/Flickr, CC BY-SA

̽��ֱ��problem with these theories is that they depend on evolution being a sort of one-step game, where one change produces a great leap forward, one from which other changes cascade. But the record does not support this. We split from our last common ancestor with the chimpanzees 5-6m years ago. But when we look at human ancestors between then and now, we do not find a single moment of dramatic change. Instead, it was cumulative – some 4m years ago we started walking upright on two legs, and about a million years later we started using stone tools. ̽��ֱ��size of our brains only started enlarging about 2m years ago.

Certainly there were periods that involved a more dynamic series of changes than others. For example, there was one at the beginning based on how hominins moved across the landscape, becoming bipedal and ranging over larger areas. Then about 2-3m years ago, there was another period of changes when brain size started to increase and childhood and adolescence periods started getting longer. This was coupled with boosts in technology and resource acquisition, such as hunting and gathering.

A final such period occurred in the last half million years, when cognitive changes associated with language, cooperation and cumulative culture – such as the development of more complex and composite technology, and the use of material culture for symbolic purposes – came to the fore. But even these periods, each lasting hundreds of thousands of years, were multi-event processes.

̽��ֱ��big picture

As far as we can tell, human evolution is like a mosaic of change, made up of many small steps, each of which adds a piece to what it is to be human. Only at the end do we see the full configuration, but had we stopped the clock at any point along that continuum, we would have seen a different mosaic. Human evolution is not one great transition, therefore, but many smaller ones.

Part of the problem in trying to see the big pattern of human evolution is that we look at it through the lens of the present – how we are today is the guide to how we were in the past. But the past was different in so many ways, and our extinct relatives show some surprising departures from what we expect when we base those expectations on ourselves.

̽��ֱ��remains of a Neanderthal wikimedia, CC BY-SA

Take body size. In the developed world, we are big, and sadly getting bigger in unhealthy ways. Better nutrition has led to increased body mass in many populations across the world. We also associate being large with being human, as it was thought that our ultimate ancestors, the australopithecines (living in Africa between about 4m and 2m years ago) were small, and that our own genus, Homo, marked a substantial increase in body size.

But that may not have been the case. In fact, nearly all the early, extinct species and subspecies of Homo were small, if not very small. ̽��ֱ��global average human body weight (combined sexes) now is over 60kg. No fossil hominin until the Neanderthals and modern humans reached an average of 50 kg, and most were below 40 kg – half the size of the average American male. Pygmy populations in Africa and Asia also weigh about 40kg, which means that most early and extinct hominins were pygmy sized. There are many advantages to large body size – such as resisting predators, access to larger prey – and the fact that our earliest ancestors did not become large tells us a lot about the energetic constraints under which they lived and reproduced.

We may picture our ancestors as rugged versions of ourselves, tall and strong, but they were not. We need to start thinking of them as creatures that were as unique as ourselves, but in different ways.

Understanding more about human evolution will depend on finding more fossils and applying more and more powerful scientific techniques. Ancient DNA, for example, is revealing extraordinary new details about our recent past. As important, however, will be using our greater knowledge of the overall pattern of human evolution, its tempo and mode, to inform us about the cumulative processes by which we became human, rather than expecting that with one great evolutionary bound, our hero was free.

Robert Foley, Professor of Human Evolution, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

Robert Foley (Department of Archaeology and Anthropology) discusses the cumulative processes by which we became human.

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Australopithecus afarensis reconstruction

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Tool use is 'innate' in chimpanzees but not bonobos, their closest evolutionary relative

fpjl2 — Tue, 16 Jun 2015 08:22:36 +0000

Chimpanzees and bonobos are the two closest living relatives of the human species - the ultimate tool-using ape. Yet, despite being so closely related on the evolutionary tree, wild chimpanzees and bonobos differ hugely in the way they use tools.

Chimpanzees show the most diverse range of tool use outside of humans. For example, chimpanzees use sticks to 'fish' for ants and termites, stones to crack nuts, as well as tools for grooming and communication. Bonobos rarely use tools and never to forage for food.

̽��ֱ��question of 'what makes a tool user?' is a key one in human evolution, says researcher Dr Kathelijne Koops, and the origins of human tool mastery could lie in the gulf between tool use in chimpanzees and bonobos.

Is it to do with the environment the apes live in and the surrounding opportunities for tool use? Or perhaps the opportunities to learn from other apes through social contact? Or something deep-rooted. Something intrinsic.

Koops, in collaboration with colleagues from Kyoto ̽��ֱ��, conducted painstaking research tracking communities of wild chimpanzees and bonobos in Uganda and Congo for months, cataloguing not just all tool use, but also all potential for tool use in terms of the different environments and social time spent.

They also investigated the innate propensity for object manipulation in young apes, regardless of whether said object was deployed as a 'tool' - the first wild inter-species comparison of its kind.

̽��ֱ��researchers found that environmental opportunities did not explain the difference in tool use. From nut trees to ant nests, stones to shrubs, the bonobos had access to as many tools and promising foraging opportunities in their stomping ground as the chimpanzees.

Nor did social opportunities. In fact, young bonobos spent more time with their mothers, and had more individuals in close proximity for more time whilst feeding than young chimpanzees. Young bonobos also had more social partners than young chimpanzees.

However, immature chimpanzees manipulated and played a lot more with objects than bonobos, and played with objects on their own. This was a difference already visible in very young individuals, says Koops. In fact, she says this is the first evidence for a species difference in the innate predisposition for tool use in our closest evolutionary cousins.

"Chimpanzees are object-oriented, in a way that bonobos are not," said Koops, who conducted the work at Cambridge ̽��ֱ��'s Division of Biological Anthropology and at Zurich ̽��ֱ��'s Anthropological Institute and Museum.

"Given the close evolutionary relationship between these two species and humans, insights into the tool use difference between chimpanzees and bonobos can help us identify the conditions that drove the evolution of human technology.

"Our findings suggest that an innate predisposition, or intrinsic motivation, to manipulate objects was likely also selected for in the hominin lineage and played a key role in the evolution of technology in our own lineage," she said.

̽��ֱ��research is published today in the journal Scientific Reports.

Inset image: Young Bonobos Engaged in Social Play. Credit: Kathelijne Koops

First evidence for a species difference in the innate predisposition for tool use in our closest evolutionary cousins could provide insight into how humans became the ultimate tool-using ape.

Insights into the tool use difference between chimpanzees and bonobos can help us identify the conditions that drove the evolution of human technology

Kathelijne Koops

A Young Chimpanzee Playing with Twigs

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Saharan 'carpet of tools' is the earliest known man-made landscape

fpjl2 — Wed, 11 Mar 2015 16:29:13 +0000

A new intensive survey of the Messak Settafet escarpment, a massive outcrop of sandstone in the middle of the Saharan desert, has shown that stone tools occur “ubiquitously” across the entire landscape: averaging 75 artefacts per square metre, or 75 million per square kilometre.

Researchers say the vast ‘carpet’ of stone-age tools – extracted from and discarded onto the escarpment over hundreds of thousands of years – is the earliest known example of an entire landscape being modified by hominins: the group of creatures that include us and our ancestral species.

̽��ֱ��Messak Settafet runs a total length of 350 km, with an average width of 60 km. Parts of the landscape are ‘anthropogenic’, or man-made, through build-up of tools over hundreds of thousands of years.

̽��ֱ��research team have used this and other studies to attempt to estimate the volume of stone tools discarded over the last one million years of human evolution on the African continent alone. They say that it is the equivalent of more than one Great Pyramid of Giza per square kilometre of the entire continent (2.1 x 10¹⁴ cubic metres of rock).

“ ̽��ֱ��Messak sandstone, now in the middle of the vast sand seas of Libya, would have been a high quality rock for hominins to fracture – the landscape is in effect a carpet of stone tools, most probably made in the Middle and Upper Pleistocene,” said Professor Robert Foley, from the Leverhulme Centre for Evolutionary Studies at the ̽��ֱ�� of Cambridge, who conducted the research with colleague Dr Marta Mirazón Lahr.

“ ̽��ֱ��term ‘anthropocene’ is now used to denote the point at which humans began to have a significant effect on the environment,” said Mirazón Lahr. “ ̽��ֱ��critical time may well be the beginning of the industrial revolution about 200 years ago. Some talk of an ‘early anthropocene’ about 10,000 years ago when forests began being cleared for agriculture.

“Making stone tools, however, dates back more than two million years, and little research has been done on the impact of this activity. ̽��ֱ��Messak Settafet is the earliest demonstrated example of the scars of human activity across an entire landscape; the effects of our technology on the environment may be considerably older than previously thought,” Mirazón Lahr said. ̽��ֱ��study is published today in the journal PLOS One.

̽��ֱ��survey, conducted in 2011, involved randomly selecting plots of one metre squared across the parts of the plateau surface. In each square, the researchers sifted through all the stones to identify the number that showed evidence of modification through hominin activity – evidence such as a ‘bulb of percussion’: a bulge or curved dent on the surface of a stone tool produced by the angular blows of hominin percussion. ̽��ֱ��average number of artefacts across all sample squares was 75.

At the simple end, large flakes of stone would have been opportunistically hacked from boulders to be used for cutting or as weapons. At the more sophisticated level, researchers found evidence that specific tools had been used to wedge into the stone in order split it.

“It is clear from the scale of activity how important stone tools were, and shows that African hominins were strongly technologically dependent,” said Foley. “Landscapes such as these must have been magnets for hominin populations, either for ‘stone foraging trips’ or residential occupation.”

̽��ֱ��researchers say that if – as seems likely – the success of Stone Age communities depended significantly on tool technology, there would be enormous advantage to knowing, remembering and indeed controlling access to areas with a “super-abundance” of raw materials, such as the Messak Settafet.

“Hominins may well have become tethered to these areas, unable to stray too far if survival depended on access to the raw materials for tools, and forced to make other adaptations subservient to that need,” said Mirazón Lahr.

One way that the environmental impact of hominin tool excavation may have been positive for later humans is through the clusters of small quarrying pits dotted across the landscape (ranging up to 2 metres in diameter, and 50 centimetres in depth).

These pits would have retained moisture – with surface water still visible today after rains – and the small pools would have attracted game. In many of these pits, the team found ‘trapping stones’: large stones used for traps and ties for game and/or cattle during the last 10,000 years.

By combining their data with previous extensive surveys carried out across Africa, the researchers attempted to estimate roughly how much stone had been used as tools and discarded during human evolution.

Although stone tool manufacture dates back at least 2.5 million years, the researchers limited the estimate to one million years. Based on their and others research, they standardised population density (based on extant hunter-gatherers), tool volume, the number of tools used by one person in a year and the amount of resulting debris per tool.

They estimate an average density of between 0.5 and 5 million stone artefacts per square kilometre of Africa. When converted into an estimate of volume, this is the equivalent of between 42 to 84 million Great Pyramids of Giza.

Researchers say this would be the equivalent of finding between 1.3 and 2.7 Great Pyramids per square kilometre throughout Africa.

Researchers used the new survey of the Messak Settafet to estimate that enough stone tools were discarded over the course of human evolution in Africa to build more than one Great Pyramid for every square kilometre of land on the continent.

Landscapes such as these must have been magnets for hominin populations, either for ‘stone foraging trips’ or residential occupation

Robert Foley

Robert Foley/Marta Mirazón Lahr

Left: A view across a valley in the Messak landscape. Right: A Levallois core, a distinctive type of Middle Stone Age stone tool, recovered on the surface of the Messak

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Opportunity, and not necessity, is the mother of invention

amb206 — Wed, 12 Nov 2014 09:00:00 +0000

Whether you're a human being or an orangutan, tools can be a big help in getting what you need to survive. However, a review of current research into the use of tools by non-human primates suggests that ecological opportunity, rather than necessity, is the main driver behind primates such as chimpanzees picking up a stone to crack open nuts.

An opinion piece by Dr Kathelijne Koops of the ̽��ֱ�� of Cambridge and others, published today (12 November 2014) in Biology Letters, challenges the assumption that necessity is the mother of invention. She and her colleagues argue that research into tool use by primates should look at the opportunities for tool use provided by the local environment.

Koops and colleagues reviewed studies on tool use among the three habitual tool-using primates – chimpanzees, orangutans and bearded capuchins.

Chimpanzees use a variety of tools in a range of contexts, including stones to crack open nuts, and sticks to harvest aggressive army ants. Orangutans also use stick tools to prey on insects, as well as to extract seeds from fruits. Bearded capuchin monkeys living in savannah-like environments also use a variety of tools, including stones to crack open nuts and sticks to dig for tubers.

̽��ֱ��researchers’ review of the published literature, including their own studies, revealed that, against expectations, tool use did not increase in times when food was scarce. Instead, tool use appears to be determined by ecological opportunity with calorie-rich but hard-to-reach foodstuffs, such as nuts and honey, appearing to act as an incentive for an ingenious use of materials.

“By ecological opportunity, we mean the likelihood of encountering tool materials and resources whose exploitation requires the use of tools. We showed that these ecological opportunities influence the occurrence of tool use. ̽��ֱ��resources extracted using tools, such as nuts and honey, are among the richest in primate habitats. Hence, extraction pays off, and not just during times of food scarcity,” said Koops.

Tool use – and transmission of tool-making and tool-using skills between individuals – is seen as an important marker in the development of culture. “Given our close genetic links to our primate cousins, their tool use may provide valuable insights into how humans developed their extraordinary material culture and technology,” said Koops.

It has been argued that culture is present among wild primates because simple ecological and genetic differences alone cannot account for the variation in behaviour – such as tool use – observed across populations of the same species.

Koops and co-researchers argue that this ‘method of exclusion’ may present a misleading picture when applied to the material aspects of culture.

“ ̽��ֱ��local environment may exert a powerful influence on culture and may, in fact, be critical for understanding the occurrence and distribution of material culture. In forests with plenty of nut trees, we are more likely to find chimpanzees cracking nuts, which is the textbook example of chimpanzee material culture,” said Koops.

“Our study suggests that published research on primate cultures, which depend on the ‘method of exclusion’, may well underestimate the cultural repertoires of primates in the wild, perhaps by a wide margin. We propose a model in which the environment is explicitly recognised as a possible influence on material culture.”

̽��ֱ��opinion piece ‘Ecological conditions influence primate cultures’ is published by Biology Letters. ̽��ֱ��authors are Kathelijne Koops ( ̽��ֱ�� of Cambridge, Archaeology & Anthropology & ̽��ֱ�� of Zurich, Anthropological Institute and Museum), Elisabetta Visalberghi (CNR, Institute of Cognitive Sciences) and Carel van Schaik ( ̽��ֱ�� of Zurich, Anthropological Institute & Museum).

Inset image: a chimpanzee uses a stick to extract ants (Kathelijne Koops)

When food is scarce, tool use among non-human primates does not increase. This counterintuitive finding leads researchers to suggest that the driving force behind tool use is ecological opportunity – and that the environment shapes development of culture.

Ecological opportunities influence the occurrence of tool use. ̽��ֱ��resources extracted using tools, such as nuts and honey, are among the richest in primate habitats. Hence, extraction pays off...

Kathelijine Koops

A chimpanzee uses a stone to crack a nut

Yes

Chimpanzees have favourite ‘tool set’ for hunting staple food of army ants

fpjl2 — Thu, 16 Oct 2014 09:49:00 +0000

West African chimpanzees will search far and wide to find Alchornea hirtella, a spindly shrub whose straight shoots provide the ideal tools to hunt aggressive army ants in an ingenious fashion, new research shows.

̽��ֱ��plant provides the animals with two different types of tool, a thicker shoot for ‘digging’ and a more slender tool for ‘dipping’.

On locating an army ant colony, chimpanzees will dig into the nest with the first tool - aggravating the insects. They then dip the second tool into the nest, causing the angry ants to swarm up it. Once the slender shoot is covered in ants, the chimpanzees pull it out and wipe their fingers along it: scooping up the ants until they have a substantial handful that goes straight into the mouth in one deft motion.

This technique - ‘ant dipping’ - was previously believed to be a last resort for the hungry apes, only exploited when the animal’s preferred food of fruit couldn’t be found. But the latest study, based on over ten years of data, shows that, in fact, army ants are a staple in the chimpanzee diet - eaten all year round regardless of available sources of fruit. Ants may be an important source of essential nutrients not available in the typical diet, say researchers, as well as a potential source of protein and fats.

̽��ֱ��new research, published today in the American Journal of Primatology, was led by Dr Kathelijne Koops from the ̽��ֱ�� of Cambridge’s Division of Biological Anthropology and Junior Research Fellow of Homerton College.

“Ant dipping is a remarkable feat of problem-solving on the part of chimpanzees,” said Koops. “If they tried to gather ants from the ground with their hands, they would end up horribly bitten with very little to show for it. But by using a tool set, preying on these social insects may prove as nutritionally lucrative as hunting a small mammal - a solid chunk of protein.”

Koops points out that if Alchornea hirtella is nowhere to be found, chimps will fashion tools from other plants - but seemingly only after an exhaustive search for their preferred tool provider.

Previous research has shown that chimpanzees will actually select longer tools for faster, more aggressive types of army ants. ̽��ֱ��average ‘dipping’ tool length across the study was 64 centimetres, but dipping tools got up to 76 cm.

̽��ֱ��question for Koops is one of animal culture: how do chimpanzees acquire knowledge of such sophisticated techniques?

“Scientists have been working on ruling out simple environmental and genetic explanations for group differences in behaviours, such as tool use, and the evidence is pointing strongly towards it being cultural,” said Koops. “They probably learn tool use behaviours from their mother and others in the group when they are young.”

̽��ֱ��research for the ant-dipping study - which took place in Guinea’s Nimba mountains - proved challenging, as the chimpanzees were not habituated to people - so the team acted almost as archaeologists, studying ‘exploited’ ants nests to measure abandoned tool sets and “sifting through faeces for ants heads”.

To further study these illusive creatures, Koops set up cameras to take extensive video footage of the chimpanzees and their tool use. In doing so, she managed to capture a chimpanzee who has constructed a tool with which to investigate the camera itself - prodding it curiously and then sniffing the end of the tool (VIDEO).

“This study is part of a big ongoing research project. ̽��ֱ��next stages will involve looking at social opportunities to learn: how much time do youngsters spend within arm’s length of other individuals; how much time do they spend close to their mother; as well as innate predispositions to explore and engage with objects,” said Koops.

A video clip from the Kalinzu Forest in Uganda, where Koops is currently conducting comparative studies on East African chimpanzees, captures a male chimpanzee seemingly looking on enviously at a female who has managed to construct a much better dipping tool than his own and is feasting heartily as a consequence (VIDEO). Koops suggests this kind of observing of other individuals may lead to learning within a chimpanzee community.

“By studying our closest living relatives we gain a window into the evolutionary past which allows us to shed light on the origins of human technology and material culture,’’ added Koops.

Inset image: Fanwaa the chimpanzee. Credit: Kathelijne Koops

New research shows that chimpanzees search for the right tools from a key plant species when preparing to ‘ant dip’ - a crafty technique enabling them to feast on army ants without getting bitten. ̽��ֱ��study shows that army ants are not a poor substitute for preferred foods, but a staple part of chimpanzee diets.

By studying our closest living relatives we gain a window into the evolutionary past which allows us to shed light on the origins of human technology and material culture

Kathelijne Koops

K Koops YT

Kathelijne Koops

Chimp eating army ants using an 'ant-dipping' tool

Yes