Book 37

The seemingly innocent observation that the activities of organisms bring about changes in environments is so obvious that it seems an unlikely focus for a new line of thinking about evolution. Yet niche construction - as this process of organism-driven environmental modification is known - has hidden complexities. By transforming biotic and abiotic sources of natural selection in external environments, niche construction generates feedback in evolution on a scale hitherto underestimated - and in a manner that transforms the evolutionary dynamic. It also plays a critical role in ecology, supporting ecosystem engineering and influencing the flow of energy and nutrients through ecosystems. Despite this, niche construction has been given short shrift in theoretical biology, in part because it cannot be fully understood within the framework of standard evolutionary theory. Wedding evolution and ecology, this book extends evolutionary theory by formally including niche construction and ecological inheritance as additional evolutionary processes. The authors support their historic move with empirical data, theoretical population genetics, and conceptual models.
They also describe new research methods capable of testing the theory. They demonstrate how their theory can resolve long-standing problems in ecology, particularly by advancing the sorely needed synthesis of ecology and evolution, and how it offers an evolutionary basis for the human sciences. Already hailed as a pioneering work by some of the world's most influential biologists, this is a rare, potentially field-changing contribution to the biological sciences.

Book 39

In 1951, the geneticist Luigi Luca Cavalli-Sforza was teaching in Parma when a student--a priest named Antonio Moroni--told him about rich church records of demography and marriages between relatives. After convincing the Church to open its records, Cavalli-Sforza, Moroni, and Gianna Zei embarked on a landmark study that would last fifty years and cover all of Italy. This book assembles and analyzes the team's research for the first time. Using blood testing as well as church records, the team investigated the frequency of consanguineous marriages and its use for estimating inbreeding and studying the relations between inbreeding and drift. They tested the importance of random genetic drift by studying population structure through demography of the last three centuries, using it to predict the spatial variation of frequencies of genetic markers. The authors find that drift-related genetic variation, including its stabilization by migration, is best predicted by computer simulation. They also analyze the usefulness and limits of the concept of deme for defining Mendelian populations.
The genetic effect of consanguineous marriage on recessive genetic diseases and for the detection of dominance in metric characters are also studied. Ultimately bringing together the many strands of their massive project, Cavalli-Sforza, Moroni, and Zei are able to map genetic drift in all of Italy's approximately 8,000 communes and to demonstrate the relationship between each locality's drift and various ecological and demographic factors. In terms of both methods and findings, their accomplishment is tremendously important for understanding human social structure and the genetic effects of drift and inbreeding.

Book 93

A number of scholars have found that concepts such as mutation, selection, and random drift, which emerged from the theory of biological evolution, may also explain evolutionary phenomena in other disciplines as well. Drawing on these concepts, Professors Cavalli-Sforza and Feldman classify and systematize the various modes of transmitting "culture" and explore their consequences for cultural evolution. In the process, they develop a mathematical theory of the non-genetic transmission of cultural traits that provides a framework for future investigations in quantitative social and anthropological science. The authors use quantitative models that incorporate the various modes of transmission (for example, parent-child, peer-peer, and teacher-student), and evaluate data from sociology, archaeology, and epidemiology in terms of the models. They show that the various modes of transmission in conjunction with cultural and natural selection produce various rates of cultural evolution and various degrees of diversity within and between groups.
The same framework can be used for explaining phenomena as apparently unrelated as linguistics, epidemics, social values and customs, and diffusion of innovations. The authors conclude that cultural transmission is an essential factor in the study of cultural change.