New Scientist - The Essential Guides

The Essential Guide series brings together the best recent coverage from New Scientist specially curated into beautiful compendiums about the most exciting themes in science and technology today. Written and edited by some of the world’s best science writers, these guides will leave you with everything you need to know about subjects from nutrition to the solar system and more.

OUR HUMAN STORY

New Scientist - The Essential Guides

THE NEW FOSSIL STORY

BONES OF CONTENTION • Who do we think we are? Modern humans, descended from a long line of Homo sapiens? Distant relatives of those great adventure-seekers who marched out of the cradle of humanity, Africa, 60,000 years ago? Members of a species whose origins can be traced back to a common ancestor with chimpanzees? The sole survivor of a lineage of apes whose brains have been getting progressively bigger for millions of years? Whatever answer we might be tempted to give, new fossil finds suggest the true tale of our origins is a lot more complex.

REWRITING OUR TIMELINE • In the early 2000s, the standard story of how we evolved from a chimp-like ancestor seemed linear and logical. Then came two decades of relentless and confounding discoveries

THE EARLIEST HUMANS • Around 2 million years ago, some hominins began to evolve key traits that we associate with humans. We put them in a new genus, Homo. But our ideas about the early Homo species are changing – as is the notion that hominins became progressively more sophisticated until our species eventually emerged.

FOUR RARE EARLY ANCESTORS • Some of our ancestors are known only by small fossils: a toe bone here, a jaw fragment there. In those cases, it is all we have to build the story of human evolution. The following four early African hominins are some of the rarest of all. If and when we find more evidence, maybe their stories will change the most.

HOW TO DATE A FOSSIL • The discovery of weird bones in strange places seems to be the new normal in palaeoanthropology. But, interpreting these physical remains is not easy. As well as comparing the anatomy of different specimens, fossils must also be dated. Until recently, our ability to do this was limited.

A 21ST-CENTURY FOSSIL HUNTER

THE ORIGIN OF OUR SPECIES

AFRICA – BUT WHERE AND WHEN? • Much as with the wider story of the emergence of hominins we surveyed in chapter 1, new discoveries are forcing a rethink on almost all fronts when it comes to the origin of our own species, Homo sapiens. A simple story built up over recent decades depicted the evolution in relatively short order of a species that resembled us first in body, and then in brain. The reality, it seems, is far messier than that.

THE MAKING OF THE MODERN MIND

OUR RAINBOW ORIGINS • How can Homo sapiens have originated as many distinct populations that were nevertheless all one species? In truth, the story seems even stranger than that: it looks as if this diversity persisted in Africa for most of our species’ existence.

WHAT ANCIENT DNA TELLS US

THE GHOSTS WITHIN US • The genetics revolution has transformed our ability to delve into our ancestry. It also has profound implications for how we see ourselves. Where early genetic studies seemed to indicate that our ancestors never interbred with other hominins, we now know that many of us possess genes from several other species. What’s more, some of the fossils in our DNA are “ghosts”, mystery species unknown from bones, tools or other artefacts that may never be identified.

HOW DNA REVEALS OUR PREHISTORY

OUR ANCIENT INHERITANCE • Dozens of genes found in humans today have been traced to Neanderthals and Denisovans, a legacy of interbreeding between our direct ancestors and these now-extinct lineages. Some of this “undead” DNA has proved very useful in making us what we...