Understanding Human Evolution: The Making of Infrastructure, Property, and Political Culture in Twentieth-century Calcutta

Tattersall is commendable in his approach, clarifying the controversies and avoiding the dogmatism that has often characterized this field. He presents the available evidence, scant as it is, in an accessible and understandable way leading us to the current thesis of why homo sapiens survived and flourished while all our hominin relatives went extinct. For those interested in paleoanthropology, this is a fine place to begin your journey.

It would be easy to write a relatively dull book about human evolution. This book is simply fascinating. The author readily admits where the fossil record is lacking and acknowledges the questions that yet to have good answers. His coverage of the history of paleontology is excellent and provides the reader with insights into both the various personalities involved as well as the sources for current controversy in the field. His coverage of the Neanderthals, their fall, and the concurrent rise of Homo Sapiens is top notch. His included commentary about who “we” are in the truly grand scale of things provides food for deep thought. I’d enthusiastically recommend this book for anyone with even a passing interest in the subject matter.

Being myself a scientist in the geo field I found this little book well-written. It provides a flavor on the topic.

This excellent book gives a very useful overview of human evolution, including: (1) The methods used by scientists try to find out the facts. (Some of this part of the book gets rather technical.) (2) The history of the scientific search for knowledge of human origins. (3) The current state of knowledge, and the current debates and controversies. (Controversies based on conflicting interpretations of the genetic and fossil evidence.) In this review, I am just going to focus on Tattersall’s views on two major current debates about the origins of modern Homo sapiens. Firstly, there is the debate about where H. sapiens originated. To follow this debate, it is necessary to know that there are two types of evolution. Firstly, there is anagenesis. This is where there are evolutionary changes WITHIN a species over time. For example, if the environment (physical, biological or climatic) of an entire species gradually changes, then natural selection could lead to the whole species itself gradually changing. The other type of evolution is cladogenesis. This is where a new species branches off from an existing one. This speciation process usually takes place when a peripheral population of a species becomes geographically isolated. When this happens, this isolated population can evolve relatively rapidly (in geological terms) into a new species. (This view is compatible with Gould and Eldredge’s theory of “Punctuated Equilibrium”.) There is a currently influential theory which says that modern H. sapiens did not originate in one place. This theory is called African Multiregionalism or the Pan-African Network model. It says that there were semi-separated populations of a pre-sapiens species (probably Homo heidelbergensis) spread right across Africa. Each population developed slightly different features, but they occasionally interbred. When this happened it led to modern H. sapiens, which is therefore a composite, rather than a result of speciation in one place. This means, in effect, that H. sapiens appeared as a result of anagenesis, not cladogenesis, and that there is really no distinct boundary between H. sapiens and H. heidelbergensis. (Taken to its logical conclusion, it seems to me that it could end up with seeing all the species in the Homo genus as just one big species developing via anagenesis.) Although Tattersall does not specifically mention this “Network” theory in this particular book, he certainly puts forward a view which totally contradicts the theory. Tattersall opts instead for the importance of cladogenesis, with H. sapiens first appearing in an isolated population and then spreading across Africa to replace other Homo species – quite possibly with some interbreeding with them, as there was later with Neanderthals after H. sapiens had spread out of Africa, because speciation is a process and it takes time for total reproductive isolation to develop. Personally, I’m only an interested amateur, but I find Tattersall’s view more convincing than the Network/African Multiregionalism model. The second area of debate which Tattersall is involved in relates to when language and modern human consciousness first developed. Some scientists have in the past claimed that in the history of our own species (Homo sapiens) there was a “creative explosion” in Europe about 40,000 years ago (with the appearance of cave art etc), long after the appearance of the species itself 200,000 or 300,000 years ago. They claimed that this “Great Leap Forward” was caused by some biological change to the brain, possibly linked to the development of language. In his best-selling book “Sapiens” (which is not taken seriously by the scientific community because of its speculative nature), Harari has put forward a similar idea of a “Tree of Knowledge” genetic mutation 70,000 years ago. But this idea of some (invisible and unprovable!) biological change to the brain either 40,000 or 70,000 years ago has been shot down in recent years by the discovery of evidence for art and sophisticated tools dating from much earlier than the time that the “Great Leap Forward” is supposed to have happened. Back to Tattersall. Like the advocates of the “Great Leap Forward”, he also believes that modern symbolic consciousness appeared long after Homo sapiens first evolved. But he argues that the modern brain, with all its full, modern potential, appeared with the first H. sapiens, but that this potential was not fulfilled until much later when H. sapiens started to use symbols and fully-developed language for social/cultural reasons. It seems to me that there are problems with Tattersall’s view on this. Firstly, there is more and more evidence of art being found that dates back to well before 100,000 years ago. (Tattersall says that this is not proper, symbolic art.) Secondly, it could be that a lot of symbolic art was created very early on, but this has either not survived or not been discovered yet. (As the archaeologists say, “Absence of evidence is not evidence of absence.”) Thirdly, there seems to be some evidence that language goes back much further than Tattersall suggests, even possibly to Neanderthals and H. heidelbergensis). (Though, again, Tattersall says that this was not fully-developed modern language.) We certainly need to remember that, even if there was a “creative explosion”, it should not be assumed that behavioural change must be determined by biological change. Why does cultural change have to imply a change to the brain? It is more likely that the brain had become “modern” when Homo sapiens first evolved, and that any later cultural change took place for non-biological reasons. After all, the development of farming 12,000 years ago, of cities and writing 5,000 years ago, and of industry 200 years ago were also “Great Leaps Forward”, but no one believes that these were the result of genetic changes to the human brain. Apologies for this review being rather long. But I find these two debates fascinating. Anyway, I recommend this book.

I am a retired genetics professor, and for years I have enjoyed the exciting and rapidly expanding field of human evolution. There have been many research articles and books to read, but it has been difficult to get an overall picture of this field. This is the best book I have read. It is only 182 pages, but it is the most comprehensive and concise presentation that I have found.