The Cradle of Humanity: How the changing landscape of Africa made us so smart
Mark Maslin
Oxford University Press, 2019
234pp, 53 black & white illustrations
Paperback, £9.99, $14.95

Europe: A Natural History
Tim Flannery
Allen Lane, 2018
346pp, eight colour plates
Hardback, £25

The Smart Neanderthal: bird catching, cave art and the cognitive revolution
Clive Finlayson
Oxford University Press, 2019
228pp, 13 black & white and four colour illustrations
Hardback, £20, $27.95

Human Origins
New Scientist Instant Expert, 2018
241 pages, 21 black & white illustrations
Paperback, £12.99

We humans are a complicated lot; capable of acts of kindness and of sublime creativity. Yet we also perpetrate gross destructiveness and wanton carelessness. Such is our impact on the earth system – through deforestation, soil erosion, pollution of air and water and the destruction of our fellow creatures – that in 2000 Paul Crutzen and Eugene Stoermer suggested that our planet had entered a new geological era, the Anthropocene or 'the era of humans'.

Small creatures have left their mark in the past, such as the single-celled algae (Coccolithophore) whose minute skeletons, in their zillions, make up the beds of chalk, exposed by the English Channel (La Manche) at the White Cliffs of Dover and at Cap Gris Nez. These algae created geological deposits on a world scale – beyond France into Russia and as far afield as Texas and Western Australia.

In death, these creatures laid down the strata of the Cretaceous period, around 100million years ago. Yet our own influence is more insidious; a sudden shock to the world's system.

Geologists in the distant future, of whatever species they happen to be, will find that the strata we left behind are formed of an infinite number of fragments of plastic. They may also observe a void – the disappearance of many, many living creatures. About 500 species have already gone in the course of the 20th century alone. At this rate we are set to out-pace the KT (Cretaceous–Tertiary) extinction of 66 million years ago which disposed of most of the dinosaurs – and which opened the door to the Cenozoic Era ('recent life'). This allowed scurrying, shrew-like mammals to emerge into the light and evolve into us, the new masters and monsters of the Universe.

Most geologists agree that the Anthropocene has now started. So, when did it begin? Paul Crutzen pinned the blame on the Industrial Revolution, the surge in power and pollution which spread from Britain and Europe to the USA and Asia from about 1800. Others argue that our world-wide impact is more recent: kicking off in the 20th century with vast changes to habitats, agriculture, transport and population growth. Or should we look further into our past? Perhaps to the rapid widespread adoption of farming, from about 6000 years ago, which began the transformation of the biosphere. Arguably, there have been interruptions: the pandemics of the late Classical World, the Middle Ages and the holocaust of the native populations of the Americas may have briefly reduced the human impact on the Earth and its climate.

There is no doubt that, in the words of the Chinese curse, 'we live in interesting times'. It would be easy to resort to pessimism and fatalism, which would be as pointless as burying our heads in the chalk and refusing to face up to the reality of what is happening: the mess we are making of the only planet known to support life. The good news is that we are also making great strides in understanding that planet, the evolution of life, and even ourselves. Perhaps it was overweening arrogance to label ourselves Homo sapiens but, in some respects, we can live up to the name. We are the only species that can work out where we came from and, on a good day, understand the consequences of our actions.

During my lifetime, we have taken the most amazing strides towards exploring the universe, documenting the origins of the Earth and the development of life upon it. The scientific literature is usually highly technical and often impenetrable for most of us. Fortunately we are blessed with some great synthesisers, people who can turn the complex '-ologies' into plain and even vivid language, capture the excitement of new discoveries and confront their implications.

Mark Maslin, Professor of Earth System Science at University College, London, is one such person: a messenger of brevity and clarity. His books Climate: A Very Short Introduction (2013) and Climate Change: A Very Short Introduction (2014) delivered exactly what it said on the covers. The Human Planet: How we created the Anthropocene (2018), co-authored with Simon L Lewis, is essential reading for anyone concerned about our future. Now he has written The Cradle of Humanity: How the changing landscape of Africa made us so smart, which vividly explains the human past in relation to the deep history of the Earth. The 'cradle' is Africa, where humans evolved and emerged at only four seconds to midnight if Earth's history is represented as a single day.

From Africa, the bifurcated, big-brained, tool-using ape strode around the world to generate a current population of 7.5 billion and growing. Mark Maslin puts the human species into the context of a constantly changing planet of how plate tectonics – itself a relatively recent discovery and a phenomenon at present unique to earth – has shifted oceans and continents, built mountain ranges and changed the climate. The changing earth drives evolution. And the course of evolution has created an ultra-social species that now lives, with a remarkable degree of co-operation, in complex, urban jungles. Maslin's excellent little book explains why we are all ancestral Africans who adapted to rapid environmental change by evolving big brains which we pool by living together.

The Australian scientist and explorer Tim Flannery is another of the world's great synthesisers, who combines the disciplines of palaeontology, zoology and climatology with awesome fluency. If Maslin examines humans in the context of geomorphology, Flannery, in his new book Europe: A Natural History, sees us as an animal species, one element in the web of life. Admittedly, we are a species with an exceptionally heavy footprint. The International Union of Geological sciences defines the Anthropocene as beginning when humans start to leave an indelible and widespread stamp on the Earth's sediments. Flannery suggests that we have, in effect, put a halt to the glacial cycles of the Pleistocene, and that the point at which our greenhouse gases prevented a future Ice Age mark the beginning of the Anthropocene – in other words around the turn of this century.

The fascination of Flannery's book is that in a series of short, vivid chapters he provides snapshots of what a remarkably changeable, and seemingly exotic land Europe has been over the millennia. By illustrating how rhino, elephants, hippo, crocodiles and large cobras and python-like snakes have lived in Europe, he opens up interesting ideas about conservation and the re-introduction of species, or what is sometimes called 're-wilding' (I am not wildly keen on the term).

Where I live in a 'post-agricultural' area of France, we have seen the return of beaver, red squirrels, martens, lynx, wolves and, only two weeks ago, we spotted a golden jackal for the first time. I am delighted but the nearby shepherds are unhappy. So, how would they feel about living alongside forest elephants, lions or aurochs, the giant cattle of prehistoric Europe? Flannery makes us think about Europe in a different way – through the deep lens of a palaeozoologist. Our close relatives, the Neanderthals, only arrive in Chapter 25 of Europe. Oddly, Flannery claims they are an African species.

Most scientists believe Neanderthals evolved in Europe, possibly from Homo heidelbergensis. In popular culture, Neanderthals are portrayed as hairy, beetle-browed, knuckle-draggers; in 1866 the German biologist Ernst Haekel proposed the species name Homo stupidus. In contrast, no one has done more for Neanderthal public relations than evolutionary archaeologist Clive Finlayson.

As the title of his most recent book, The Smart Neanderthal: bird catching, cave art and the cognitive revolution, suggests, Neanderthals were clever and caring. I suspect that if Clive had a daughter who brought home a Neanderthal as her new fiancée he would have no objections. And why should he? Recent genetic studies show that we certainly interbred and as much as 60% of the Neanderthal genome survives in Homo sapiens today.
As a keen bird-watcher, I found The Smart Neanderthal fascinating. The principal feature of the book is the
importance of birds, which provided food and feathers for the Neanderthals who lived on Gibraltar. Since the 1980s, Clive Finlayson and his colleagues have been investigating these people who lived around Gorham's Cave. I have spent many years, myself, sieving for bird bones and they are not easy to find. Yet, the Gibraltar team remarkably identified over 60 species surviving from over 30,000 years ago.

It has often been said that because Neanderthals could only catch, or forage off, big lumbering species, their diet was limited. Small, supposedly fast creatures like birds and rabbits were safe until Homo sapiens arrived with nets, arrows and dogs. Finlayson quite rightly points out that this is nonsense – probably the idea of archaeologists who had never hunted themselves. Also, the Gibraltar deposits show that Neanderthals lived in a world which could have been a bird-watchers paradise, where ground and cliff-nesting birds were prey to these versatile hominins.

Around 20 years ago scientists presented a reasonably coherent account of the last half million years of human evolution. Homo heidelbergensis, big-brained and athletic, spread out of Africa, made sophisticated javelins, and killed and butchered rhinoceros below the chalk cliffs at Boxgrove, Sussex. Neanderthals evolved in Europe and western Asia, while Homo sapiens, who also first appeared in Africa, began to colonise the world about 60,000 years ago. With their superior skills and organisation, modern humans replaced, or even wiped out, the thinly scattered bands of Neanderthals.

Now, a spate of recent discoveries has muddied the waters. Most recently Homo sapiens remains have been found in Greece dated, surprisingly early, to 150,000 years ago. In 2004, the skeleton of a small hominin, dated to about 17,000 years ago, turned up on the Indonesian island of Flores. More recent discoveries, and fresh dating, indicate these small humans have a much older ancestry in the region.

In South Africa, cavers squeezed into the deep, narrow Rising Star system and found the remains of some 18 individuals. These hominins, named Homo naledi, had small brains and projecting jaws but their teeth, feet and hands were more evolved. This mixture of ancient and modern features is puzzling because of their age – dated to about 285,000 years ago. How did primitive Homo naledi survive alongside highly developed humans?

In addition to fossil evidence, DNA research is also provoking new questions. Did modern humans benefit from interbreeding with Neanderthals? Who exactly were the Denisovans, possibly an off-shoot of Neanderthals, recognized in 2008 from a finger bone found in a Siberian Cave? Denisovan DNA has now been identified in the modern Melanesian population. An admirably clear account of recent developments can be found in Human Origins: Seven million years and counting (New Scientist Instant Expert, 2018).

The emergence of modern humans is not as straightforward as it once appeared. We did not rise to a position of god-like superiority in an uncertain world. But, if we use our big brains and powers of co-operation, the Earth might still benefit from our presence, otherwise the name Homo stupidus could be revived and applied to the species that really would deserve it.

David Miles

 

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