This book presents a new picture of human evolution. It is one that stems, in part, from treating fossils more as we generally treat living forms. But it is also one that comes, in part, from what we learn by studying the living forms as though they were fossils.
Thinking of fossils as living forms is the reverse of what is usually done in studies of fossil primates. It means thinking of fossils as populations and as two sexes, even although we cannot actually know which individual specimens are in which populations, nor of which sex. Such a procedure better helps display the varieties of structures that exist, than when only one or a very few fossil specimens or subjects, are available for study. As a result of adopting such a strategy, this book is forced to concentrate on dimensions of teeth, because these are the only remains that are numerous enough to allow it.
Thinking of living forms as fossils is also the reverse of what we usually do. Living forms, are of course, usually studied in situations where we know the populations and the sexes from information independent of the data. Thinking of living forms as though they were fossils, means examining living forms as though we did not know population and sex for each specimen. The comparison between these two sides of the coin helps powerfully in understanding the situation in fossils where only the one side is available.
Treating the fossils more as though they were living forms also means looking at comparisons, without making the assumption that any particular fossils are on the same lineages as others. This is also different from that usually done in studies of primate fossils where, in contrast to paleontological studies of other organisms, it seems that investigators of human evolution are mainly trying to establish ancestors. Even although different species have existed at different times, this is a 'holy grail' of a task. It is generally most unlikely that fossils separated by any great amount of time one from another are ever in actual ancestral-descendent relationships to one another. Not assuming lineages allows us far more freedom to follow where our data lead, prevents us from posing the kinds of evolutionary speculations that are untestable, and takes us into a more objective assessment of individual fossils, and their relationship to our own evolution.
It is in these ways that this book differs from many others. Yet it has not been written in a vacuum. It follows from a great deal of work on human evolution that has been carried out over the centuries.
This is the fourth book in a series. The first two are an initial pair. Form and Pattern in Human Evolution: Some Mathematical, Physical and Engineering Approaches, and Uniqueness and Diversity in Human Evolution: Morphometric Studies of Australopithecines. Form And Pattern describes some modern methods available for the study of biological structure, with resulting implications for understanding biological function. Uniqueness and Diversity then applies these methods to particular supposed human ancestors, the australopithecinae. The results are interesting. On the one hand a series of general analytical methods are explained and used in ways that meet with wide approval from many scientific colleagues in biology. These methods are now applied in the study of form throughout the life sciences. On the other hand, specific results about australopithecines are anathema to many anthropologists, suggesting as they do that the australopithecines may not be as close to humans as is generally thought.
Since those books were published early in the seventies, my investigations have expanded. They now include a wider range of methods for studying biological form and pattern that are based in mathematics, physics and engineering. And they now span a far wider range of anatomical regions and animals: most parts of the body and most of the members of the Order Primates.
Thus a second pair of volumes, The Order of Man: A Biomathematical Anatomy of The Primates, and this book, Fossils, Teeth and Sex: New Perspectives on Human Evolution naturally came about. The Order of Man is an attempt to expand the use of morphometric methods, widely defined. In contrast, however, to the earlier Form And Pattern its chief aim is to apply the most well worked out of the methods, multivariate morphometrics, to as many of the living members of the Order Primates as possible. It is, as the title indicates, mainly about the living primates. In the part of that book, that deals with primate fossils, I was unable to take into