biological sciences

This book, one of the teaching tools for Human Biology Core at Stanford, is a great read. Klein takes the reader through human evolutionary history in a concise writing style. The most fascinating element in the book is Klein's argument for the "dawn of culture" occurring 50 kya, providing both evidence for and critiques of this view.

The sweep of human evolution has received much attention in recent years. This book is among the more sweeping efforts aspiring to reveal who we are. Fossils of our ancestors are being revealed at an increasing rate. From these scattered bones and teeth [and a few artefacts], a more complete picture of our evolutionary path is emerging. The evidence from the bones is being complemented by genetic studies filling in the details of human migration over the planet. If nothing else has been derived from these multi-disciplinary studies, our ancient origins in Africa is now undisputed, say the authors.

There's another element almost hidden away by the growing amount of evidence. What kind of path did hominid species follow in becoming human? That question forms the basis of Klein and Edgar's "bold new theory" clamouring from the cover. They contend the fossil and genetic evidence displays human evolution as a series of long, slack stretches of development, both physical and mental, interrupted by bursts of innovation in body and brain. Each burst, building on what had gone on before, seems to them a form of the "great leap forward". They contend the evidence in bones, especially skulls, indicates spurts of brain encephalisation. This means not only larger brains, but more elaborate ones - capable of complex thoughts, foresight, enhanced communication skills and symbolism - in short, culture. Although the bones and skulls are geographically scattered and the art and artefacts few and far between, the authors contend they have drawn the path of human development clearly and conclusively. Human evolution followed a path of long stretches of equilibrium, punctuated by episodes of rapid change.

"Punctuated"? "Equilibrium"? The authors concede early in the book that this isn't an original idea with them. It's derived from the attention-seeking proposal of Stephen Gould and Niles Eldredge a generation ago. "Punk eek" keeps struggling for survival and the road of human evolution is its sole remaining support. There's a delicious irony in this, given Steve Gould's ambivalent attitude toward human evolution. Ostrich eggshell beads are intriguing, but far less important than how we developed hunting strategies. Rock tools and stick weapons are features we share with our chimpanzee relatives - a notion "punk eekers find distasteful.

Klein's bringing Blake Edgar's writing talents to this book was inspired thinking. What Edgar granted to Don Johanson in clarity he has duplicated here. Combining his prose skills with Klein's wealth of illustrative material and wide knowledge of the discipline has produced a cogent, readable text. Unfortunately, Edgar's campaign strategy of inserting Gould into the scenario is less compelling. The theory is thus neither "bold" nor "new". How significant it is in describing the human condition awaits more evidence than is currently available. Given that so much of it rests on brain development, real data is unlikely to be forthcoming. However, it's worth waiting for. Pass the time delving into the wealth of information in this book. [stephen a. haines - Ottawa, Canada]

Klein tells the six million-year-old story of human evolution from a "splitter's" perspective. Accordingly, H. habilis is distinguished from rudolphensis, and the Asian H. erectus from the African ergaster and the European antecessor. Neandertals are accorded some humanity, but are treated as a separate species. They evidently lacked the inferred genetic mutation for modern speech that supposedly arose some 50 kya. While Klein avoids any mention of the earlier evidence for speech, and argues away inconvenient dates, he offers a coherent synthesis of all the recent data.