Innholdsfortegnelse for EG04 i New Scientist - The Essential Guides

THE human story starts somewhere in Africa with one ape learning to walk upright, and ends with one of their descendants dominating the world. It is a fascinating, yet frustratingly incomplete, tale – and one that seems to gain added complexity every time a new fossil bone or piece of DNA evidence is found. As with its three predecessors in the Essential Guide series, this volume is curated from the best content from New Scientist’s recent archive, specially revised and updated to bring you up to speed with the latest developments. It covers a lot of ground, from our earliest African origins to a discussion of some of the qualities, such as our morality, our art and our language, that have made us uniquely successful. To that list we might…

7 MYA SAHELANTHROPUS TCHADENSIS (ANNOUNCED 2002) Strange ape skull with some human-like features suggests our ancestors split from chimps more than 7mya 4.4 MYA “ARDI” ARDIPITHECUS RAMIDUS (2009) Ardi walked on two legs but may have lived in woods, suggesting hominins first walked upright in forests 6 MYA ORRORIN TUGENENSIS (2001) Species the size of a chimp with human-like teeth. Its thigh bone suggests it was bipedal. Some say it may be closer to modern humans than Lucy 3.5 MYA KENYANTHROPUS PLATYOPS (2001) Contemporary with Lucy’s species. Some say it was closer to modern humans than australopiths 1.75 MYA DMANISI SKULL (2002) This subspecies of H. erectus found in Georgia has traits belonging to three different early Homo species. It shows that some small-brained humans left Africa 2 MYA AUSTRALOPITHECUS…

Little more than a decade ago, the first ancient genome was sequenced. This huge technical achievement opened a whole new window on our past, and promised intimate insights about our interactions with now-extinct members of our family tree. Since then, palaeogeneticists have been probing more ancient fossils to find out how they fit in. They have also devised ways to uncover our pre-human ancestry by peering into the genomes of living people from around the world – with results that upend preconceptions about our heritage still further.…

HOMO SAPIENS spread across the world almost entirely on foot. Ancestral humans walked out of Africa, through or around Arabia to south Asia, over to eastern Asia, and via various routes to Europe. They even walked to the Americas over a land bridge that once stretched from present-day Siberia to Alaska. The only major land mass that had to be reached by sea was Sahul, a lost continent that included Australia, New Guinea, Tasmania and a lot of what is now seabed. Setting out for Sahul would have been an astonishing leap of faith. It was far offshore, requiring a voyage of many days across a chain of islands separated by deep, open sea, sometimes with little sight of land. The waters around the island groups are treacherous, and it…

The discovery of a pint-sized hominin on the Indonesian island of Flores in 2003 kicked off a new era in palaeoanthropology. Before that, many fossil hunters had assumed that there was little material evidence of human evolution still to be unearthed. Afterwards, anything seemed possible. And the “hobbit”, as this new species was quickly dubbed, defied all expectations of what a member of our genus might look like and where it could be found. We now know it wasn’t the only unusual hominin in the neighbourhood. FROM the start, Homo floresiensis, aka the hobbit, has been an evolutionary puzzle. It had a strange mix of features: a short body, unusually long feet, and a surprisingly tiny brain. Those are features that wouldn’t look out of place in an early species…

Language is our most versatile tool. It can transmit information about the past, present and future, formalise ideas, trigger action, persuade, cajole and deceive. Without language, human society would have been impossible. By piecing together clues from anatomy and genetics, we are starting to see when language emerged. The real surprise that story contains is that we may not have been the only communicative hominin. AT LEAST since biblical times, people have puzzled over the origins of language. It is, after all, one of the few traits that distinguish humans from all other animals. Even among the hundreds of other primate species, not one has a communication system that comes close to it in its flexibility and infinite range of expression. Unfortunately, the story of how language evolved is written…

Fossil finds have traditionally been the foundation on which we built our understanding of the human story. But, over the past few years, some extraordinary finds, including of physical remains from ancestors we never even imagined might exist, have called into question almost every assumption we had made. Our understanding is still far from complete, but the new insights have unsettling implications for how long we have walked on Earth, who our ancestors were and where we really come from, and, indeed, who we even are. Our new human story starts here.…

BY THE middle of the 20th century, researchers were beginning to accept that humans evolved in Africa from an ancient group of “ape people” called the australopiths. In 1960, a research team at Olduvai Gorge in Tanzania found fossil remains of a species that seemed to fall in the gap between the australopiths and humans. It originated sometime before 2 million years ago and was extinct by around 1.5 million years ago. The researchers identified it as the first true human species to evolve – the original member of our genus Homo – and they named it Homo habilis. From the fragmentary fossils found, H. habilis seemed to have had a brain substantially larger than an australopith’s and more like that of later human species. What’s more, according to its…

THE idea that each of our cells might contain fragments of genetic code from extinct hominins has been around for decades. The problem was identifying what those genetic sequences might look like. To do that, you would need to sequence ancient DNA and then compare it with the modern equivalent sequences. But DNA degrades with time. It would take special fossils and special skills to extract it from very old bones, particularly if they had spent thousands of years buried in a hot climate, as our African ancestors have. Geneticists began to show an interest in archaeological remains in the late 1990s. With the technology available then, they managed to sequence a small chunk of mitochondrial DNA (mtDNA) – the genetic material in the cell’s powerhouse – from an ancient…

THE idea that hybrids are in some way unnatural and of lower intrinsic value is surprisingly common. You see it most clearly in decisions about conservation where hybrids are often considered less worth of protection. In fact, this view is outdated. It arises from the assumption that species, at least in the animal kingdom, are distinct once formed. In the past few decades, however, biologists have been astonished to discover that the opposite is true: hybridisation between animal species is common. Genetic analysis reveals, for example, that the critically endangered red wolf is a cross between the grey wolf and coyote. Likewise, one of the world’s rarest fish, the Devil’s Hole pupfish, seems to be a hybrid. Now we know that the hybrid issue extends all the way to our…

WE DON’T know exactly when humans first reached the New World. The consensus is that the first Americans arrived fairly recently, about 15,000 years ago. It is also widely believed that they did so via Beringia – an area centred on the Bering Strait between Siberia and Alaska, which was dry land at that time. This implies that the story of the first Americans began with a subarctic odyssey. Although Europe and Asia has been home to hominins for almost 2 million years, it seems none of the earliest inhabitants – including Homo erectus, Neanderthals and Denisovans – strayed much above 55° north, roughly in line with the top of what are now Ireland and Kazakhstan. There’s every reason not to do so: it isn’t just cold, there also aren’t…

The story of the origin of our own species, Homo sapiens, once had a neat linearity about it. We evolved in eastern Africa between 200,000 and 150,000 years ago, became capable of modern behaviour some 60,000 years ago and then swept out of Africa to colonise the world, completely replacing any archaic humans we encountered. The origins of our species do indeed lie in Africa, but discoveries of new fossils and tools, plus analyses of ancient and modern DNA, are tearing apart any neatness to the narrative beyond that. With the dust yet fully to settle, the question now is how many, if any, of our old assumptions still hold.…

IMAGINE visiting a tourist attraction in any major world city. There are people from all over – a Nigerian family, a Chinese couple, a German school party, and more. They all look very different from one another, which isn’t surprising given that their ancestors have lived in far-flung parts of the world for generations. Yet, everyone alive today can trace their origins back to Africa, so there must have been a time when such physical differences didn’t exist, right? Actually, no. In fact, if you were to travel back to the very beginnings of our species and select a random group of humans, they would look unlike anyone living today in Africa or elsewhere. What’s more, they would show extraordinary physical variation – greatly exceeding that in modern human populations.…

Genetics is now at the leading edge of human evolution research but extracting information about the past from DNA isn’t straightforward. The techniques rely on arcane statistics and computational biology. However, the basic principles are easy to grasp. One key thing that DNA can tell us is how long ago two lineages diverged, for example, when the ancestors of Neanderthals and Homo sapiens split. These analyses are based on mutations, says Carina Schlebusch at the University of Uppsala in Sweden. The simplest method uses mitochondrial DNA, a self-contained mini genome found inside cells’ mitochondria, which produce energy. This is passed on directly from mothers to their offspring. “We sequence different mitochondrial genomes and then compare and count the different mutations between them,” she says. “Then, using the rate at which…

As we have seen in previous chapters, fossil and DNA evidence suggest that our ancestry isn’t so much a family tree as a tangled family bush, with many more branches and interconnections than we knew. We have very little evidence of what life was like for most of these other hominins. But for a few more recent members of our family that we’ve already encountered – the Neanderthals, the Denisovans and the diminutive “hobbit” – we are putting together a richer picture.…

WHEN she first saw the necklace, Genevieve von Petzinger feared the trip halfway around the globe to the French village of Les Eyzies-de-Tayac had been in vain. The dozens of ancient deer teeth laid out before her, each one pierced like a bead, looked roughly the same. It was only when she flipped one over that the hairs on the back of her neck stood up. On the reverse were three etched symbols: a line, an X and another line. Von Petzinger, a palaeoanthropologist from the University of Victoria in Canada, is spearheading an unusual study of cave art. The first formal writing system that we know of is the 5000-year-old cuneiform script of the ancient city of Uruk in what is now Iraq. But it and other systems like…