Biological anthropologists aim to explain the hows and whys of human biological variation using the concepts of evolution and adaptation. High-altitude environments provide informative natural laboratories with the unique stress of hypobaric hypoxia, which is less than usual oxygen in the ambient air arising from lower barometric pressure. Indigenous populations have adapted biologically to their extreme environment with acclimatization, developmental adaptation, and genetic adaptation. People have used the East African and Tibetan Plateaus above 3,000 m for at least 30,000 years and the Andean Plateau for at least 12,000 years. Ancient DNA shows evidence that the ancestors of modern highlanders have used all three high-altitude areas for at least 3,000 years. It is necessary to examine the differences in biological processes involved in oxygen exchange, transport, and use among these populations. Such an approach compares oxygen delivery traits reported for East African Amhara, Tibetans, and Andean highlanders with one another and with short-term visitors and long-term upward migrants in the early or later stages of acclimatization to hypoxia. Tibetan and Andean highlanders provide most of the data and differ quantitatively in biological characteristics. The best supported difference is the unelevated hemoglobin concentration of Tibetans and Amhara compared with Andean highlanders as well as short- and long-term upward migrants. Moreover, among Tibetans, several features of oxygen transfer and oxygen delivery resemble those of short-term acclimatization, while several features of Andean highlanders resemble the long-term responses. Genes and molecules of the oxygen homeostasis pathways contribute to some of the differences.
Cynthia M. Beall and Kingman P. Strohl
Andrew I.R. Herries
The identification of the Taung Child Australopithecus africanus type specimen as an early human fossil (hominin) by Raymond Dart in 1924, followed by key discoveries at sites like Sterkfontein, Swartkrans, and Makapansgat in the 1930s and ’40s, was key to understanding that humans first arose in Africa, not Europe or Asia. Later discoveries in eastern Africa have shown that the earliest potential hominins (e.g., Orrorin tugenensis) date back to at least 6 million years ago. In contrast, the oldest fossils hominins in South Africa are those of Australopithecus from the sites of Taung and Makapansgat and are dated to between about 3.0 and about 2.6 million years ago (Ma); only one specimen, from Sterkfontein, potentially dates to earlier than this sometime between 3.7 and 2.2 Ma. However, the majority of early hominin fossils in southern Africa come from 2.8- to 1.8-million-year-old palaeocave remnants in the Malmani dolomite of the Gauteng province. These sites have a rich record of hominin species, including Australopithecus africanus, Australopithecus sediba, Paranthropus robustus, and Homo erectus. Most of these species, except for Homo erectus, are endemic to South Africa. However, the DNH 134 specimen from Drimolen Main Quarry does represents the oldest fossil of Homo erectus anywhere in the world. This specimen occurs at a time around 2 Ma when there is a turnover in hominin species with the extinction of Australopithecus and the first occurrence of Homo, Paranthropus, and an archaeological record of Oldowan and bone tools. Acheulian technology occurs from at least 1.4 Ma and is associated with specimens simply attributed to early Homo. The oldest hominin fossil outside the northern Malmani dolomite karst is dated to between 1.1 and 1.0 Ma, at Cornelia-Uitzoek in the Free State, and also represents the last specimen defined as early Homo. Paranthropus is also last seen around 1 million years ago, when the first specimen attributed to Homo rhodesiensis may also have occurred at Elandsfontein in the Western Cape. There is a dearth of hominin fossils from the terminal Early Pleistocene until the late Middle Pleistocene when a high diversity of hominin species occurs between about 340,000 and about 240,000 years ago (c. 340 and c. 240 ka). This includes a late occurring specimen of Homo rhodesiensis from Broken Hill in Zambia, Homo helmei or early modern humans from Florisbad, and Homo naledi from Rising Star. This is also a period (post 435 ka) containing both late occurring Acheulian and early Middle Stone Age (MSA) technology, but none of these fossils is directly associated with archaeology. Definitively early modern human fossils are not found until after 180 ka in direct association with MSA technology, and the majority, if not all, of the record occurs during the last 120 ka.
Charles H. Klein
Since Francis Crick and James D. Watson’s discovery of DNA in 1953, researchers, policymakers, and the general public have sought to understand the ways in which genetics shapes human lives. A milestone in these efforts was the completion of the Human Genome Project’s (HGP) sequencing of Homo sapiens’ nearly three million base pairs in 2003. Yet, despite the excitement surrounding the HGP and the discovery of the structural genetic underpinnings of several debilitating diseases, the vast majority of human health outcomes have not been linked to a single gene. Moreover, even when genes have been associated with particular diseases (e.g., breast and colon cancer), it is not well understood why certain genetically predisposed individuals become ill and others do not. Nor has the HGP’s map provided sufficient information to understand the actual functioning of the human genetic code, including the role of noncoding DNA (“junk DNA”) in regulating molecular genetic processes. In response, a growing number of scientists have shifted their attention from structural genetics to epigenetics, the study of how genes express themselves in particular situations and environments. Anthropologists play roles in these applications of epigenetics to real-world settings. Their new theoretical frameworks unsettle the nature-versus-nurture binary and support biocultural anthropological research demonstrating how race becomes biology and embodies social inequalities and health disparities across generations. Ethnographically grounded case studies further highlight the diverse epigenetic logics held by healthcare providers, researchers, and patient communities and how these translations of scientific knowledge shape medical practice and basic research. The growing field of environmental epigenetics also offers a wide range of options for students and practitioners interested in applying the anthropological toolkit in epigenetics-related work.
Bernard Wood, Dandy Doherty, and Eve Boyle
The clade (a.k.a. twig of the Tree of Life) that includes modern humans includes all of the extinct species that are judged, on the basis of their morphology or their genotype, to be more closely related to modern humans than to chimpanzees and bonobos. Taxic diversity with respect to the hominin clade refers to evidence that it included more than one species at any one time period in its evolutionary history. The minimum requirement is that a single ancestor-descendant sequence connects modern humans with the hypothetical common ancestor they share with chimpanzees and bonobos. Does the hominin clade include just modern human ancestors or does it also include non-ancestral species that are closely related to modern humans? It has been suggested there is evidence of taxic diversity within the hominin clade back to 4.5 million years ago, but how sound is that evidence? The main factor that would work to overestimate taxic diversity is the tendency for paleoanthropologists to recognize too many taxa among the site collections of hominin fossils. Factors that would work to systematically underestimate taxic diversity include the relative rarity of hominins within fossil faunas, the realities that many parts of the world where hominins could have been living are un- or under-sampled, and that during many periods of human evolutionary history, erosion rather than deposition predominated, thus reducing or eliminating the chance that animals alive during those times would be recorded in the fossil record. Finally, some of the most distinctive parts of an animal (e.g., pelage, vocal tract, scent glands) are not likely to be preserved in the hominin fossil record, which is dominated by fragments of teeth and jaws.
Pamela R. Willoughby
In evolutionary terms, a modern human is a member of our own species, Homo sapiens. Fossil skeletal remains assigned to Homo sapiens appear possibly as far back as 300,000 or 200,000 years ago in Africa. The first modern human skeletal remains outside of that continent are found at two sites in modern Israel, the Mugharet es Skhūl and Jebel Qafzeh; these date between 90,000 and 120,000 years ago. But this just represents a short, precocious excursion out of Africa in an unusually pleasant environmental phase. All humans who are not of direct sub-Saharan African ancestry are descended from one or more populations who left Africa around 50,000 years ago and went on to colonize the globe. Surprisingly, they successfully interbred with other kinds of humans outside of Africa, leaving traces of their archaic genomes still present in living people. Modern human behavior, however, implies people with innovative technologies, usually defined by those seen with the earliest Upper Paleolithic people in Eurasia. Some of these innovations also appear at various times in earlier African sites, but the entire Upper Paleolithic package, once known as the Human Revolution, does not. Researchers have had to split the origin of modern biology and anatomy from the beginnings of modern cultural behavior. The first clearly evolves much earlier than the latter. Or does it?
Stacy Lindshield and Giselle M. Narváez Rivera
While anthropological primatology is known for its basic research on understanding the human condition from comparative and evolutionary perspectives, its applied and practicing domains are equally important to society. Applied researchers and practitioners often work in the fields of environmental sustainability and conservation, biomedicine, captive care and management, and education. For sustainability and conservation specializations, primatologists seek careers in higher education, government, and nongovernmental organizations and may work in large and diverse teams on conservation and management problems for nonhuman primates (hereafter, termed primates). Primate conservation has largely focused on population monitoring in protected and unprotected areas; measuring effects of agriculture, extractive industries, and tourism on primates; and evaluating intervention strategies. Primate population management in urban and peri-urban areas is a growth area; these landscapes pose risks for primates that are absent or rare in protected areas, which include dog attacks, animal–vehicle collisions, and electrocutions. Anthropologists can leverage their deep knowledge of primate behavior, cognition, and ecology as part of interdisciplinary teams tasked with environmental mitigation in these human-centered landscapes. One example of this work is the use of arboreal crossing structures for primates to move safely through forests fragmented by roads. Primate conservationists recognize that environmental sustainability extends beyond conservation. For instance, primates may create public health problems or nuisances for local communities in cases where they are potential disease vectors. While these circumstances lead some people to view primates as pests, in a subset of these cases, cultural norms and values prohibit culling (i.e., killing or otherwise removing from a population) as a management strategy. Primate conservationists working on these issues may integrate human perspectives and attitudes toward primates in localized intervention or mitigation programs aimed at environmental sustainability and/or natural resource management. More than half of the world’s nonhuman primate species are threatened with extinction, and this problem is mostly a modern and global phenomenon related to unsustainable land use. Primates enhance many societies through providing ecosystem services, enriching cultural heritage, and advancing scientific research. It is for these reasons that primatologists often contribute to conservation programs in protected areas. Protected areas are designed to allow wildlife to flourish in spaces by restricting land use activities, but the history of protected areas is fraught with social injustices. Such areas are often but not always associated with higher biodiversity than adjacent and unprotected spaces. People and primates have shared spaces since time immemorial, often in sustainable ways. In addition, allocating a majority of primate range areas to fortress-style protection is at odds with the economic growth models of some primate range countries (i.e., nations with indigenous wild primates). Furthermore, many primatologists recognize that conservation benefits from integrating social justice components into programs with the ultimate goal of decolonizing conservation. Primate conservation continues to build on the foundation of basic and applied research in protected areas and, further, contributes to the development of community conservation programs for environmental sustainability. Examples of these developments include participating in offset and mitigation programs, introducing ethnographic methods to applied research to evaluate complex social processes underlying land use, and contributing to the decolonization of primate conservation.
Amber Wutich, Melissa Beresford, Teresa Montoya, Lucero Radonic, and Cassandra Workman
Anthropological thinking on water security and scarcity can be traced through four scholarly approaches: political ecology of water scarcity, water insecurity, water economics, and human-water relationality. Political ecologists argue that water scarcity a sociopolitical process and not necessarily related to physical water availability. The political ecological approach is concerned with power, global-local dynamics, and how water scarcity is unevenly distributed within and across communities. Water insecurity research is concerned with how injustice and inequity shape household and individual variability in water insecurity. Inspired by biocultural research, water insecurity scholars have used systematic methods to advance theories of how water insecurity impacts mental health, food insecurity, dehydration, and other human biological outcomes. Economic anthropologists explore how economic dynamics—including formal and capitalist economies, noncapitalist and hybridized economies, reciprocity, social reproduction, and theft—shape water scarcity and insecurity. Research priorities in economic anthropology include water valuation, meanings of water, and water as an economic good. Building from Indigenous scholars’ insights, relational approaches argue that humans have reciprocal obligations to respect and care for water as a living being. Water justice, these scholars argue, requires restoring human-water relations and upholding Indigenous sovereignty and self-determination. All four of these research areas—scarcity, insecurity, economics, and relationality—are producing cutting-edge research, with significant implications for research agendas in the anthropology of water security and scarcity.