The Incredible Human Journey

Title: The Incredible Human Journey – The Story of How We Colonised the Planet

Author: Alice Roberts

Publisher:  Bloomsbury, 2009 (First)

ISBN: 978-0-7475-9839-8

Pages: 333

Alice Roberts is a qualified medical doctor and has been a lecturer in Anatomy at the University of Bristol in U.K. She is interested in paleoanthropology and evolutionary anatomy. She has a PhD in paleopathology – the study of diseases in ancient bones. She writes and talks about science and works closely with the BBC. This book is the story and lessons obtained when she traveled around the world, retracing the footsteps of our ancestors who toddled out of Africa in the dawn of prehistory and went on to establish empires of adaptation to hostile environments and social networks around the globe. Even without the convenience of technology propping them up on artifacts custom-made for their ventures, the forefathers crossed imposing seas, navigated mighty rivers, and beachcombed to reach all the continents except Antarctica. Roberts tells the epic story from the source in Africa to the destinations at many places around the world by visiting the prominent locations where archeological record has materialized fossils and stone tools to provide clues about how the ancient people lived, worked and died.

Roberts presents the book as easily approachable by any class of readers. Unlike most other books, the fundamental concepts are not taken for granted as something they already know about. Instead, each is given a brief, but adequate explanation. In the introducing chapter, she prepares the groundwork by listing out the ages of paleontological record, evolution of hominins and the methods by which archeologists measure the age of artifacts. We learn that a new method called Luminiscence Dating has been invented to assess the age of interesting objects buried in the ground. This is much accurate and gives the age of the sample after it was last heated. Crystals of natural quartz release electrons as a result of being subjected to ionizing radiation from other radioactive materials or cosmic radiation. These will be trapped in crystal faults and will be released only when they are heated. When it is buried, heating is no longer possible and electrons continue to accumulate in faults. By measuring the amount of electrons, we get the age of the sample. The method works best for items which are a few years old to millions of years.

Though hominins were in existence for the last two million years, modern humans are thought to have originated as a separate species in East Africa around 200,000 years ago. Being in the Pleistocene era, it was a time of glacials (Ice age), with few warm intervals called interglacials in between. Human fossils of this period have been found in the Omo valley in Ethiopia. Then, probably due to climatic fluctuations, they moved on to Asia, by two possible routes through Egypt or across the Red Sea to Arabia. Being a glacial period, the deserts were very arid, and sea level was about 80 m lower. The early people could cross over to Arabia by sailing across the waters which was only 11 km wide. Roberts visits India, Malaysia and Australia to trace the probable route our ancestors must have taken in colonizing the world. The migration might have occurred along the coast, since that way, people could continue with their essentially marine food sources. However, the sea level has considerably risen from the levels 60,000 or 70,000 years ago. The earliest settlements, if there were any, would probably be under the sea, several kilometers outward from the present coastline. Very few fossils had been discovered from Asia for this period, though plenty of stone tools were recovered. The possibility of coexistence of modern humans with other hominin species also may have to be suspected, as evidenced by the discovery of Homo floresiensis, a sub-species of dwarf-people identified to have lived in Flores Island of Indonesia until as late as 10,000 years ago. Such finds give credence to the much supported, but academically unsupported hypothesis of ‘muti-regionalism’ as against ‘Out of Africa’ theory. Its proponents argue that humans evolved separately from different homo species in several parts of the world and it accounts for the differences between various races.

The original emigrants from Africa seems to have split into two groups in India, with one branch going north through Khyber Pass to Central Asia and Siberia. The other group went east along the Himalayan valley to South East Asia. They further diffused north to China and invented agriculture by planting rice. Roberts finds in modern China a government clinging dearly to the notion that Chinese people have descended from a unique lineage of Homo erectus, and not from Africa. Ideas of patriotism and racial superiority underline such extravagant and baseless claims. The author points out fossil evidence and also scientists from China itself who oppose this theory. Migration to Europe started side by side with this development. People who went there seem to have run the chance of sharing the land with Neanderthals, our closest homo cousins. Though not conclusively proved, it is widely believed that the two species lived alongside each other in Europe. Increased competition for the same resources, inter-species conflicts, and failure in adapting to fluctuating climate would have resulted in the extinction of Neanderthals. Modern humans took over Europe thereafter and development of social networks are seen in cave art demonstrated in many French caves like Lascaux. Meanwhile in Levant, agriculture developed as indicated by a recent find in Gobekli Tepe in Turkey. Initially, it brought about a decline in life expectancy due to restricted diet and epidemics, but increased growth rate of population offset the down trend. Agriculture gradually spread around the world.

People from East Asia crossed over to the Americas around 20,000 years ago and spread there. Bering Straits, which separates Alaska and Siberia today, was a vast landmass in those times of glaciation, so crossing over was not an issue. The diffusion across the continent are attested by remnants of Clovis cultures at various locations in the continent. Extinction of mega fauna like mammoth, mastodons and the like also occurred with the human spread. Probably our ancestors might have killed them off, or devastating climate change might have taken its toll. There is another curious theory explained in connection with the extinction. Around 13,000 years ago, a comet of small asteroid is believed to have exploded over North America, evidenced by a layer of black ash seen in many places on the continent. The extinction seems to be contemporaneous with this. However, this is only a hypothesis which requires extensive proof to be taken into the corpus of knowledge. Roberts ends her journey by traveling south to Chile, to the coast known as Mont Verde.

The book is neatly written, with a distinct thread of readability presented by every page in the volume. The most likely reason for this seems to be the fact that the author is not a diehard paleontologist who usually measure time in ­–zoic eras. The volume is immensely made attractive by a large collection of good quality colour plates collected across the author’s journey around the globe. Since the travel was sponsored by BBC as a part of television series, the book is not really meant to be taken too seriously.

This volume is in fact a mixture of the author’s travelogue of her 6-months old journey as part of a BBC television series and the paleontological content was developed mainly for the show. The ambitious title don’t do justice to the content. As a consequence, it lacks the grace of a travelogue and the punch of an anthropological work. However comprehensive was Robert’s attempts to develop the glossary, there are some ideas which she has left undescribed, such as human haplogroups like L1, M and N, which were never elucidated in detail. Towards the end, the author muses on the future course of action in front of humanity. To mitigate human-induced climate change, she advises to aim for ‘low-tech’, less energy-hungry life styles (p.332). Nonetheless, the concept that low-tech is energy efficient is plain wrong. On closer examination it may be seen that it is energy-wasting. What we should aim for is energy-efficient solutions, which would obviously be high-tech.

The book is highly recommended.

Rating: 3 Star