Before the Dawn: Recovering the Lost History of Our Ancestors [Paperback]

"Before the Dawn" is a very well written survey of what genetics can teach us about the origin and evolution of the human species. Starting with the common ancestor of humans and chimpanzees 5 million years ago, Wade explores the latest theories about the development of the "hominid" line and explains why homo sapiens evolved differently from our cousins, the chimpanzees and the bonobos.

Most of the books about human origins tend to focus on paleoanthropology and related disciplines. "Before the Dawn" does a great job of synthesizing the discoveries of paleoanthropolgists with the findings of geneticists--in some cases, examination of human DNA has confirmed what paleoanthropolgists have long believed, in others it has raised new and sometimes disturbing questions.

Without becoming overly technical, Wade explains how scientists use the study of DNA to determine when signficant events occurred in human evolution--for example, when humans began to use fully modern language (about 50,000 years ago), the size of the ancestral population of modern humans (as small as 150 people), or when the ancestral population left the African continent (also around 50,000 years ago).

Some of Wade's observations may surprise and trouble many people. Creationists will not be pleased with the book's basic view that Darwin's theory of natural selection is absolutely correct and that it applies to people as well as animals. Others will be troubled by the ideas that our DNA contains evidence that our ancestors practiced cannibalism; that homo sapiens wiped out the Neanderthal and Homo ergaster populations in genocidal warfare that spanned millenia; that hunting and gathering societies are much more warlike than modern, settled ones; that our DNA suggests that humans became more sociable and less violent roughly 15,000 years ago, finally enabling human societies to settle down and begin farming; that human evolution did not stop 10,000 or 50,000 years ago as some have argued, but that it continues down to the present day and will continue into the future (either naturally or artificially); that in rare cases, unusual selection pressures have produced populations that, on average, are either more intelligent or more physcially capable in certain respects than others. Wade handles each of these delicate propositions with care, but some will be disturbed by the implications of what he is saying. (Perhaps that's why E.O. Wilson, in the blurb on the back of the book, praised Wade's "courage and balance.")

"Before the Dawn" is a superb survey of what scientists know (or think they know) about human origins in 2006. But this is a report from the cutting edge of genetics and paleoanthropology, so stay tuned for further developments. In the meantime, Wade's book is an excellent introduction to a new dawn of knowledge.

Drawing on a wealth of resource material, Wade builds a comprehensive picture of who we are and where we come from. The "origins" question has been pretty well solved. Darwin's insight that Africa was humanity's home base has been verified in several ways. It is the issue of human traits, their origins and expression, that's in need of clarification. Wade has scoured the research to derive some interesting, and to some, highly disturbing, conclusions.

Writing to his defined audience, Wade's use of Biblical metaphor touches a nerve. It's a useful technique as he opens with 'Genetics & Genesis'. There's no doubt in the reader's mind that 'genetics' will be the guiding theme as this book progresses. Genetics and DNA analysis have 'enriched our view of the past', he notes. He assures us, as well, that the processes they depict are still working to guide us into the future. He lists some of the insights these tools have given us. The clear continuity between 'the ape world of 5 million years ago and the human world that emerged from it' opens the inventory, which includes cultural input and various social factors, why our global dispersal was so rapid, and how language impinged on our development as a species.

Among the more captivating aspects of our evolutionary track is the number alternative paths we might have followed. Wade explains how ape diversity has made discernment of our lineage an onerous task. An indication of what's to follow emerges in a section on why we became 'naked'. The loss of fur meant that exposed skin required protection from the African sun. All humanity's skin cells contain melanin, with variations determined by geographic location. The human diaspora out of Africa led to many variations in our make-up. In many ways, we became different as we wandered the face of the globe. Wade proposes that our migrations were encouraged as much by emerging cognitive skills and development of changed relations between the sexes. Another trigger may have come from 'an ancient gene' - FOXP2. Widespread among mammals, FOXP2 underwent significant changes in our species. It's now known to be a major factor in our language skills. Language, often used as the means to reconcile differences, has also led to changes in our relationships from mates to masses of others. Disputes are subject to the use of deception and aggravation. The result, according to a cluster of researchers Wade has read or interviewed, suggests our capacity to wage war is widespread and of long history. Warfare among chimpanzees implies an inherited trait of deep lineage. The 'cultural' influences merely exacerbate what is already in place.

After explaining how our species distributed itself around the globe, he describes the 'Settlement' process and how it led to agriculture. We take both community and farming as a given today, but it's a very recent alteration from our heritage. Perhaps of more significance is that 'settlements' occurred in widely dispersed sites at various times. The conditions leading to farming and its subsequent changes in human behaviour also were different. What prompted us to take this step? Agriculture resulted in a change from social equality to a hierarchical structure. 'Leaders' were needed for planning and implementation of field use, crop distribution and resource allocation, especially water. It's an interesting facet of this transformation that agriculture emerged where water's availability was dodgy. Religion, whatever its role in hunter-gatherer times, was increasingly important in stable communities. The entire human social structure changed, with new sets of values and choices becoming the norm.

In what will certainly emerge as one the most discussed segments in this book, Wade dedicates a chapter to 'Race'. The issues are based on Wade's emphasis on how much the human genome has changed in recent [at least on an evolutionary scale] times. While the physical characteristics such as skin colour are manifest, there are other, more subtle aspects of what makes groups of us different from others. Among these are those with or lacking a tolerance for lactic acid upon becoming adults. More significantly perhaps, is the discovery that certain medications work better with some groups than others. Health issues such as these are only now being addressed. Much more work is needed and research funding may be challenging some ideological fixations.

Wade's synopsis of human evolution is among the top books issued on the topic in recent years. He has no axes of his own to grind, and blunts some dogmas in passing. The research he describes is wide-ranging. More importantly, much of it relates to how we deal with each other across lines of community, nation and humanity as a whole. While no book on the human track will be complete, nor perhaps of major importance for very long, this one will be worth keeping, and re-reading for some time. [stephen a. haines ' Ottawa, Canada]

I thought the first part of the book which was actually about the prehistory as newly discovered through DNA analysis was very interesting. I was less thrilled with the chapters on Race, Language and History. The wrap up chapter on Evolution was good, if a bit repetitious.

Wade writes extremely well and does a good job of summarizing the latest (circa 2005) research, much of which has come from analyses of the descent of the Y chromosome (from men) and mitochondrial DNA handed down through the female line. The question of our relationship with the Neanderthal--long a thorny question--is more or less resolved with DNA extracted from Neanderthal fossil bones that has been compared to the sequences of human DNA. The conclusion is that H. neanderthalensis came from H. ergaster through H. heidelbergensis as H. sapiens did, and then broke off on its own. Furthermore there is no genetic evidence that human and Neanderthal produced viable offspring. The earlier idea than the Neanderthal was a modification of the very successful H. erectus has been discredited.

As to the question of our origins, northeast sub-Saharan Africa is further confirmed as the site. Wade has humans becoming behavioral human around 50,000 years ago after becoming anatomically human as early as perhaps 200,000 years ago. The great leap forward occurring 50,000 years ago is attributed to the acquisition of symbolic, syntactic language. This was also the time when humans made the exodus out of Africa and began to colonize the world. They went east across the Red Sea at the Gate of Grief during a glacial period when the sea level was two hundred feet lower than it is today. They followed the coast line of the present Gulf of Aden and the Arabian Sea to India and eventually to Australia. I had previously though humans had gone north along the Red Sea to the Mediterranean and then east and then north to Europe. However, the evidence indicates that it was only later that humans migrated to Europe from India westward to replace the Neanderthal.

I had also always thought that agriculture came before settled communities, but it now appears that sedentism occurred first and was part of a behavioral and psychological change in humans that led to agriculture and eventually to cities and nation states. Just prior to or at about the same time as the first settlements appeared some 15,000 years ago occurred the domestication of the dog. Wade avers that living in settlements near a plentiful food source (wild grains, a bountiful river, etc.) was partially made possible by people using dogs as sentries against the ancient practice of dawn raids by neighboring tribes. Clearly the transition from the hunter-gatherer way of life to the settled way of life was a momentous one.

Perhaps the reason I wasn't so thrilled with the latter part of the book is that I read some of the studies Wade considers elsewhere. The experience of Brian Sykes in tracing the ancestry of people named "Sykes" and of Thomas Jefferson's second family with the slave Sally Hemings are examples of DNA derived stories that I had read before. Wade's account of the saga of the Ashkenazi Jews of Europe, although also a familiar story, is most interesting. He cites studies showing that Ashkenazi Jews have an average IQ of 115 while Sephardic and Oriental Jews have the usual average of 100. A couple of arguments are presented to account for this difference. The more plausible one is that because the Jews of Europe were forced by the Christian majority into becoming money lenders from about AD 1100 until around 1700. (Christianity at the time forbade usury.) That sort of intellectually demanding way of life, along with having to make a living amid persecution, selected for intelligence. By way of contrast, Sephardic and Oriental Jews during the same period "lived mostly under Muslim rulers who often forced them into menial jobs, not the intellect-demanding ones imposed on Ashkenazim." (p. 256)

More than any other book I have read, "Before the Dawn" insists on cultural change leading rapidly to genetic change. With the experience of the Ashkenazi Jews as a case in point, Wade argues more generally that "for social species the most important feature of the environment [which directs evolutionary change] is their own society." He concludes that "to the extent that people have shaped their own society, they have determined the conditions of their own evolution." (p. 267.

This might be termed "evolution by your own boot straps." I wonder however if it isn't a sort of fallacy. Biological evolution shapes human behavior which in turn leads to cultural change which leads to further biological evolution. I think it is better to speak of cultural evolution as a subset of biological evolution and not imply that somehow we have begun to direct the process. But this may be just a quibbling over semantics. Clearly the environment has changed us and we have changed the environment.

In the final chapter Wade speculates on where we are going. I always like such speculations but only really appreciate those that have us becoming post-human in some way. Wade posits one possibility that I have not thought about in years, that of humans splitting into two or more species. He notes: "Our previous reaction to kindred species was to exterminate them, but we have mellowed a lot in the last 50,000 years." (p. 279)

By the way, this idea that we "have mellowed a lot," and become less aggressive since we have domesticated ourselves is one that appears elsewhere in the book and is an idea that, for better or for worse, appears surprisingly to be true. The actually percentage of humans killed during warfare appears to have been much greater during the prehistory than it is today. The wars today are much bigger but the wars in the pre-history, according to the research presented here, were nearly constant.