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This chapter aims to summarize the results of recent research producing estimates of hominin range areas, population sizes, and land use patterns based on archaeological data. Estimates of such variables are essential to any geographic or demographic discussion of human evolution, yet at present no generally applicable quantitative method is available to link them to the often abundant data of the archaeological record. Such data offer a unique window onto the patterns of adaptation characterizing prehistoric human populations, and developing a generic method to describe trajectories of change will allow researchers to compare range areas, population sizes and land use patterns between different regions and periods from throughout the vast spatio-temporal range of human evolution. The discussion gives particular emphasis to estimating a trajectory of group size through time from shortly after 2 million years ago until approximately 14,000 years ago.

Late life was first detected in human populations, despite the very late occurrence of late life in humans. Recent data from supercentenarians provide strong evidence of a late-life mortality rate plateau in human populations. An important puzzle is why human populations reach late life so late. Two explanations are conceivable, and not necessarily incompatible with each other: (i) a generally increased mortality level under evolutionarily novel conditions due to a lack of time for age-independent beneficial substitutions to increase in frequency; (ii) a recent expansion in effective population sizes, greatly prolonging the age-range over which the effective force of natural selection declines. Regardless of its evolutionary explanation, the cessation of aging in human populations suggests new possibilities for the extension of human healthspan.

“Welcoming Limitations” argues for shifting perspectives on carrying capacity away from the definition of the maximum number of people the planet can support toward an ecological touchstone: the number of people an ecologically sound food system can support. Since the industrial food system is the most destructive, revamping the food system is imperative. This has implications for human population size. In line with Paul Ehrlich and others, the chapter argues that a population of around 2 billion is a defensible goal, enabling the conservation of biodiversity, an interconnected global civilization, and the co-flourishing of humanity and biosphere. This conclusion raises the specter of "the population question," wherein even mention of overpopulation is assailed as politically insensitive. Concerns are allayed by reframing the population question, including: redefining overpopulation as a global issue and not strictly a developing world one; clarifying that population size is a significant driver of excessive consumption, and not a variable independent of overconsumption; and countering the silence surrounding overpopulation, endeavoring to promote broad agreement about the population problem through thinking about it from new angles. Reframing the population question is followed by a discussion of a human-rights framework through which population can be stabilized and slowly reduced.

Sagebrush (Artemisia spp.) ecosystems in the western United States have changed in quantity and configuration from a variety of causes including agriculture and human population growth since Euro-American settlement. Activities sustaining human society can decrease or fragment land cover and alter ecological processes within sagebrush ecosystems. The extent of these activities, cumulatively called the human footprint, within the range of sage-grouse has not been evaluated. Using a recent human-footprint model of the western United States, a study was undertaken to evaluate human-footprint intensity: across the sage-grouse range within seven Sage-Grouse Management Zones (SMZs), across five sagebrush land-cover classes and a non-sagebrush land-cover class within SMZ, and on landscape pattern of sagebrush land cover in relation to three scenarios differing in human-footprint effect area. A landscape-pattern analysis, using a lacunarity index, or measure of sagebrush patchiness, revealed sagebrush landscapes to be multiscaled. These results support growing evidence that sage-grouse respond to environmental factors at larger scales than those currently applied in management.

This chapter examines the Earth's finitude of space and resources, noting that land areas cannot so much be changed or expanded upon as it can be reused or replaced. Although there are the possibilities of colonizing other areas of the solar system, the chapter focuses largely on the planet Earth and its own finite resources. It emphasizes the need for restraint and resourcefulness on a planet with rather daunting limits, especially in the face of the ever-growing human population. Moreover, given their population and their penchant for consumption, the human species has invariably created most of the problems that plague the Earth today. Responsible tenancy on Earth thus becomes a challenge, though not an impossible one—human knowledge is, unlike the Earth's resources, unlimited in scope.

This chapter deals with Cavalli-Sforza’s early work in the development of statistical and computer techniques to create human population trees on the basis of the genetics of blood groups. The history within was now conceived to reside in the gene. At the same time, also Cavalli-Sforza synthesized knowledge from other fields such as archaeology, linguistics, and history with the genetic data to arrive at encompassing pictures of modern human population migrations. This also generated controversy, especially with exponents of cultural anthropology. Cavalli-Sforza’s team at Stanford University was a center of human population genetic research and pioneered the development of DNA analysis for the establishment of genetic kinship trees. mtDNA and Y-chromosomal markers became the most important objects for the reconstruction of modern human evolution. On the basis of that knowledge and the out-of-Africa hypothesis, diverse branches of the human origins sciences became integrated and the new view of human evolution was popularized.

This chapter begins by reviewing important national and international policies that set the institutional context for the Serengeti ecosystem. Though the greater Serengeti ecosystem contains portions of Tanzania and Kenya, the discussion focuses on Tanzanian national policy. Policies determined at the national level in Tanzania define allowable human uses in various land designation categories. On the international level, the most important policy that affects the Serengeti ecosystem is the Convention of International Trade in Endangered Species. The chapter also examines the influence of changes in human population on the Serengeti ecosystem. The household model developed in Chapter 10 is used to simulate the impact on the Serengeti ecosystem of three potential changes in policy, economic, and demographic conditions. In particular, it explores the effects of: (1) changes in antipoaching policy; (2) the establishment of wildlife management areas; and (3) changes in human population dynamics.

Protected areas are impacted by what takes place around their borders, and the nature and severity of these impacts is influenced by reserve size, land use and human populations. Contrary to the common assumption that immigration is the result of attractive forces associated with the protected area itself, our study suggests that people in western Serengeti are being pushed from their areas of origin by lack of arable land, which they find near the protected area. Effective, targeted conservation interventions require that we move beyond broad generalizations to correctly identify both the patterns and the drivers of human population trends and their relationship to both land-cover change and protected areas on a case-by-case basis.

This chapter examines the environmental record of human population and migration in the Copan Valley, Honduras, which is the most prominent archaeological site in the region defined in this book as the Ch'orti' area. It analyzes settlement patterns and material culture and explores how data from two sediment cores extracted from under bodies of water in the Copan Valley can contribute to debates on human population in this area. The findings suggest that Maya may have arrived in the valley a couple of hundred years prior to the arrival of K'inich Yax K'uk' Mo'.

This chapter analyzes how current human population density and land use respond to environmental gradients, with an emphasis on rainfall and soil fertility, and compares this to the responses of large resident herbivores. It identifies historic shifts that led to intensified human land use in East Africa, identifying three distinct phases: hunter-gatherer, agripastoralist, and modern commercialized societies. These three historic phases of human land use are analogous to current main land use systems in the Serengeti–Mara ecosystem: (1) parks for wildlife and ecotourism; (2) protected multiple-use areas where people and wildlife coexist; and (3) the rural/village areas, with agricultural and livestock systems managed by a variety of more or less formal land tenure systems. This sets the scene for a discussion of the resource basis of human-wildlife interactions in savannas, from which we can learn to manage these interactions better in the future.

The NCA is distinctive to all of the country’s other protected areas as they are designated as Game Reserves, Wildlife Management Areas, Forest Reserves or National Parks. The NCA is currently governed by the Ngorongoro Conservation Area Authority (NCAA) under the auspices of the Wildlife Division for the Ministry of Natural Resources and Tourism (MNRT). Pressures that affect other pastoral regions such as land fragmentation, privatization, diversification and intensification of income-related activities are not common in the NCA. Rather, a complex history of conservation policies in conjunction with human population dynamics, food insecurity, disease interactions and land use changes through time informs our understanding of the current conditions of the NCA. We explore components of this system with an emphasis on human population changes, food security, wildlife-livestock dynamics and land use changes within the context of conservation policy. These factors account, in large part, for the current state of conservation and human wellbeing in the NCA. The chapter is a synthesis of scholarly literature while also providing primary data on human health and on cultivation.

This chapter explains how the partnership of Louis and Mary Leakey was of major importance in establishing the African origin and early evolution of prehistoric human populations. It then goes on to discuss early human history in general, and delves into the fossil evidence regarding our early human ancestors—from the early primates to Mary Leakey's discovery of fossil footprints made 3.6 million years ago—in an attempt to puzzle out the question of human ancestry and the origin of human and prehuman australopithecine species. But the chapter also looks further back, to the origin of the larger group of hominoids—the great apes and the lesser apes—with which we share so many features.

A number of species of amphibians have long been recognized as sliding toward extinction. For example, Houston toads (Bufo houstonensis) were first thought to be nearing extinction forty years ago, in 1962. There is evidence that humans began to effect their decline over a half century ago (in the late 1940s), and research began on the trend toward extinction in 1965. These events occurred long before the recent media hype about amphibian population declines. This chapter reviews the relevant biology of Houston toads and discusses some of the major political interactions concerning the species. It seems almost axiomatic that endangered species become involved in political entanglements, and Houston toads are no exception. Political adversaries of Houston toads have included the U.S. Fish and Wildlife Service, Texas Parks and Wildlife Department, politicians in Texas and Washington, real estate developers and other moneyed interests, and human population growth. This chapter presents accounts of the major battles in which Houston toads played a central role.

This chapter provides historical contextualization of the crisis faced by the social construction approach of race. It reveals that anatomically modern humans are a young species that spent the majority of their existence living in a narrow range of eastern Africa. Indeed the exit of our species has been pushed forward in time from previous estimates. Evolutionary forces of natural selection and genetic drift have differentiated human populations, but this differentiation has been small. Most of the signal of human differentiation occurs in noncoding loci that do not face the force of purifying selection. Within the coding loci, some adaptation to local conditions has occurred. This adaptation does not allow the unambiguous classification of human populations into biological races.