Only in Africa - The Ecology of Human Evolution
December 2, 2021
That humans originated from Africa is well-known. However, this is widely regarded as a chance outcome, dependant simply on where our common ancestor shared the land with where the great apes lived. This volume builds on from the 'Out of Africa' theory, and takes the view that it is only in Africa that the evolutionary transitions from a forest-inhabiting frugivore to savanna-dwelling meat-eater could have occurred. This book argues that the ecological circumstances that shaped these transitions are exclusive to Africa. It describes distinctive features of the ecology of Africa, with emphasis on savanna grasslands, and relates them to the evolutionary transitions linking early ape-men to modern humans. It shows how physical features of the continent, especially those derived from plate tectonics, set the foundations. This volume adequately conveys that we are here because of the distinctive features of the ecology of Africa.
... the book is exceptionally well written, and very recommendable as a foundational introduction to modern Africa savanna ecology for a readership ranging from undergraduates to professional researchers in paleoanthropology.' Manuel Domínguez-Rodrigo, Evolutionary Anthropology
‘In Only in Africa Owen-Smith presents us with copious evidence of the complexity of interactions within and between species of plants, herbivores, and carnivores, coherently linking the trophic levels. He also makes a compelling case that the early stages of human evolution could only have happened in Africa. For those willing to accept that their knowledge of relevant contemporary African ecosystems and their critical role in human evolution could do with some updating and refreshing, Norman Owen-Smith's new book provides just the help they need. Its importance for paleoanthropology cannot be exaggerated.’ Bernard Wood, Journal of Human Evolution
Demonstrates how Africa's physical features, savannas and abundant grazers enabled frugivorous apes to become savanna-living hunters.
Only in Africa. The Ecology of Human Evolution. By Norman Owen-Smith (2021). Cambridge University Press, Cambridge, 361 pp., ISBN 978-1-108-83259-5 (paperback). Paleoanthropologists have long recognized the importance of studying past climates along with the animal and plant communities, of which hominins have been members since the Late Miocene. While there is a growing recognition that those climates and communities were unlike any today (Faith et al., 2019), there can be no diminution in our efforts to understand the past and its determining impact on human evolution. Norman Owen-Smith's superb book, ‘Only in Africa,’ gives us some of the tools we need. Recognizing that ‘natural laws’ are invariant in time and space is the general approach of all science (Gould, 1965), the book provides us with the means to understand the processes and dynamics of any mammal community, paleo- or neo-. 1. The book Owen-Smith's career has been devoted to investigating the ecology of large African herbivores, first white rhino in the Hluhluwe-iMolozi Park and then kudu in Kruger National Park. Owen-Smith's book is Darwinian in scale and scope, with a rich and broad appreciation of geology, soil chemistry, and plant and animal physiology, all providing context for his interest in the short-term and longer term behavior of herbivores. Darwin's preference for Africa as the cradle of humanity was primarily based on its being the location of chimpanzees and gorillas, the two apes he accepted as having the closest relationships with modern humans (Darwin, 1871). ‘Only in Africa’ makes the case thatdfor a host of reasons explored in the bookdthe continent of Africa, because of both its physical geography and its fauna, provided a unique environmentdthe tropical savanna biomedthat was conducive to the emergence of one, or more, bipedally competent apes. At least one of these bipeds eventually shifted from an herbivorous lifestyle to one that included supplementing what was likely still a predominantly plant-based diet with meat and marrow scavenged from the carcasses of large herbivores. A book such as ‘Only in Africa’ runs the risk of falling into the trap of being determinist by providing explanations for what did occur, but Owen-Smith's strategy of focusing on processes and mechanisms as well as outcomes helps emphasize the role of contingency. ‘Only in Africa’ is divided into four parts consisting of between four and six chapters. Each chapter ends with a brief overview, and each part ends with a helpful two- to three-page synthesis. The book is organized literally ‘from the ground up.’ In part I, OwenSmith explains that although there are tropical savannas on other continents “tropical savannas outside Africa are generally rather wet and extremely dystrophic” (Owen-Smith, 2021:86). In Australia, South America, India, and southeast Asia, the grasses are different and the quality of the grazing is poorer. According to Owen-Smith, fertility in savannas is governed by the capacity of soil particles to retain mineral nutrients, such as phosphorous; nitrogen is mainly retained by the organic, humus component of the soil. The retention of mineral nutrients is increased by clay, which is preferentially generated from mafic volcanic rocks such as those in eastern Africa, whereas felsic granitic rocks generate sand. Similarly, sedimentary rocks derived from mud and silt are more clayrich than those derived from sand. He also explains how the elevation of much of the eastern side of Africa influenced the allimportant weather systems and how the nature of the bedrock influences the fertility of the soil, which along with the seasonal availability of moisture from rainfall, in turn influences the type of grasses that can flourish. In the beginning of part II, Owen-Smith explores the physical nuances and complexities of the African savanna in both eastern and southern Africa. The important variable is the presence and number of trees, referred to as ‘woody cover.’ But most of part II focuses on two arms races: one among grasses, and the other between grasses and trees. Grasses that use the C4 photosynthetic pathway are better