Showing papers in "Evolutionary Anthropology in 1998"
TL;DR: Conventional wisdom over the past 160 years in the cognitive and neurosciences has assumed that brains evolved to process factual information about the world, and attention has therefore been focused on such features as pattern recognition, color vision, and speech perception.
Abstract: Conventional wisdom over the past 160 years in the cognitive and neurosciences has assumed that brains evolved to process factual information about the world. Most attention has therefore been focused on such features as pattern recognition, color vision, and speech perception. By extension, it was assumed that brains evolved to deal with essentially ecological problem-solving tasks. © 1998 Wiley-Liss, Inc.
2,385 citations
TL;DR: If some complex traits indeed require disparities in adaptive setting (and relative fitness) in order to evolve, the VS idea counters the prevailing view that adaptive change necessitates long‐term, directional consistency in selection.
Abstract: Variability selection (abbreviated as VS) is a process considered to link adaptive change to large degrees of environment variability. Its application to hominid evolution is based, in part, on the pronounced rise in environmental remodeling that took place over the past several million years. The VS hypothesis differs from prior views of hominid evolution, which stress the consistent selective effects associated with specific habitats or directional trends (e.g., woodland, savanna expansion, cooling). According to the VS hypothesis, wide fluctuations over time created a growing disparity in adaptive conditions. Inconsistency in selection eventually caused habitat-specific adaptations to be replaced by structures and behaviors responsive to complex environmental change. Key hominid adaptations, in fact, emerged during times of heightened variability. Early bipedality, encephalized brains, and complex human sociality appear to signify a sequence of VS adaptations—i.e., a ratcheting up of versatility and responsiveness to novel environments experienced over the past 6 million years. The adaptive results of VS cannot be extrapolated from selection within a single environmental shift or relatively stable habitat. If some complex traits indeed require disparities in adaptive setting (and relative fitness) in order to evolve, the VS idea counters the prevailing view that adaptive change necessitates long-term, directional consistency in selection. © 1998 Wiley-Liss, Inc.
454 citations
TL;DR: The question of why the emergence of farming communities in the Near East was an inevitable outcome of a series of social and economic circumstances that caused the Natufian culture to be considered the threshold for this major evolutionary change is addressed.
Abstract: The aim of this paper is to provide the reader with an updated description of the archeological evidence for the origins of agriculture in the Near East. Specifically, I will address the question of why the emergence of farming communities in the Near East was an inevitable outcome of a series of social and economic circumstances that caused the Natufian culture to be considered the threshold for this major evolutionary change.1–4 The importance of such an understanding has global implications. Currently, updated archeological information points to two other centers of early cultivation, central Mexico and the middle Yangtze River in China, that led to the emergence of complex civilizations.4 However, the best-recorded sequence from foraging to farming is found in the Near East. Its presence warns against the approach of viewing all three evolutionary sequences as identical in terms of primary conditions, economic and social motivations and activities, and the resulting cultural, social, and ideological changes. © 1998 Wiley-Liss, Inc.
425 citations
TL;DR: The breaking down of food molecules via a system of both mechanical and chemical processes so that they are of use to the body is called digestion.
Abstract: Food is vital for life. It provides nutrients for growth, maintenance, and reproduction, and is the source of energy that drives the chemical reactions occurring in every cell.1,2 However, most food, as it is initially procured, is not in a form suitable for use; it must first be broken down so that it can be transported through cell membranes.1 The breaking down of food molecules via a system of both mechanical and chemical processes so that they are of use to the body is called digestion.2,3 © 1998 Wiley-Liss, Inc.
364 citations
TL;DR: This Middle Pleistocene record, still sparse but increasingly well dated, raises important questions about the fate of Homo erectus in different regions of the Old World, and how many distinct species should be recognized among the descendants of this ancient lineage.
Abstract: For paleoanthropologists working in the Middle Pleistocene, these are interesting times. New discoveries of artifacts and human fossils have been reported from western Europe, so that it now looks as though this continent was populated 800,000 years ago, if not earlier. One of the fossils, from Ceprano in Italy, is described as Homo erectus. Whether this ancient species ever reached Europe has been repeatedly questioned, but the Ceprano cranium is complete enough to provide some hard evidence. Other finds from Spain are even more spectacular. The Sima de los Huesos (‘‘Pit of Bones’’) in the Sierra de Atapuerca has yielded a wealth of skeletons that are best interpreted as early Neanderthals, perhaps close to 300,000 years in age. Older but unfortunately more fragmentary remains, also from Atapuerca, display no Neanderthal features and are claimed as representatives of a new species. Homo antecessor will require close study. These European discoveries focus fresh attention on the evidence accumulating from Africa and Asia. Human bones are known from the earlier Middle Pleistocene of Africa at localities such as Bodo in Ethiopia and Broken Hill in Zambia. The crania show anatomical features that distinguish them from Homo erectus. In the Far East, the people at Dali and other sites are also more advanced than Homo erectus, but their affinities to groups in the West are uncertain. This Middle Pleistocene record, still sparse but increasingly well dated, raises important questions. One concerns the fate of Homo erectus in different regions of the Old World. Another is how many distinct species should be recognized among the descendants of this ancient lineage. It is apparent that the traditional approach of lumping diverse humans together as ‘‘archaic’’ Homo sapiens will no longer work. The picture is highly complex, and several taxa probably are needed to accommodate the fossils. Evolutionary relationships among these populations must be clarified, but pose some major problems. I will address only a subset of these topics pertaining mainly to earlier Middle Pleistocene hominids.
261 citations
200 citations
TL;DR: Gorillas provide a unique opportunity to reevaluate proposed models of ecological influences on social organization in African apes and assess how changes in ecology influence this balance.
Abstract: Many factors influence the evolution of primate grouping patterns, including phylogeny, demographic and life-history variables, and ecological factors such as access to food, predation pressure, and avoidance of infanticide. The interaction between these factors determines social organization.1 Because western lowland and mountain gorillas differ so dramatically in their habitats and foraging strategies, they provide a valuable opportunity to assess how changes in ecology influence this balance. Mountain gorillas live in high-altitude montane forests, are herbivorous, and live in stable and cohesive groups. Western lowland gorillas live in lowland rainforest and are much more frugivorous than mountain gorillas. It is not yet clear to what extent incorporating significant quantities of fruit in the diet influences western lowland gorilla sociality because they have been studied much less than have mountain gorillas. However, what is known about their behavior hints that there may also be considerable differences in their social organization, including changes in group size and cohesion and in the frequency and type of intergroup encounters. Gorillas thus provide a unique opportunity to reevaluate proposed models of ecological influences on social organization in African apes.© 1998 Wiley-Liss, Inc.
199 citations
TL;DR: It has become apparent that the radiation leading to the modern hominoids was somewhat more recent than had been believed, and that most of the Miocene hominoid species had little to do with the evolutionary history of the living apes.
Abstract: The evolutionary history of the living hominoids has remained elusive despite years of exploration and the discovery of numerous Miocene fossil ape species. Part of the difficulty can be attributed to the changing nature of our views about the course of hominoid evolution. In the 1950s and 1960s, individual Miocene taxa were commonly viewed as the direct ancestors of specific living ape species, suggesting an early divergence of the modern lineages.1–5 However, in most cases, the Miocene forms were essentially “dental apes,” resembling extant species in dental and a few cranial features, but possessing more primitive postcranial features that suggested arboreal quadrupedalism rather than suspensory habits. With the introduction of molecular methods of phylogenetic reconstruction and the increasing use of cladistic analysis, it has become apparent that the radiation leading to the modern hominoids was somewhat more recent than had been believed, and that most of the Miocene hominoid species had little to do with the evolutionary history of the living apes. © 1998 Wiley-Liss, Inc.
192 citations
TL;DR: The purpose of this paper is to present a broad overview of the physical (anthropometric and genetic) and genetic diversities and affinities of the peoples of India and to examine how well biological, particularly genetic, diversity and aff inities correlate with geographical, socio‐cultural, and linguistic diversities.
Abstract: The Indian subcontinent comprises a vast collection of peoples with different morphological, genetic, cultural, and linguistic characteristics. While much of this variability is indigenous, a considerable fraction of it has been introduced through large-scale immigrations into India in historical times. From an evolutionary standpoint, it is of immense interest to quantify biological diversity in contemporary human populations, to study biological affinities and to relate observed patterns of affinities with cultural, linguistic and demographic histories of populations. Such efforts are intended to shed light on the peopling of India. The purpose of this paper is to present a broad overview of the physical (anthropometric) and genetic diversities and affinities of the peoples of India. I shall also attempt to examine how well biological, particularly genetic, diversities and affinities correlate with geographical, socio-cultural, and linguistic diversities and affinities. © 1998 Wiley-Liss, Inc.
158 citations
135 citations
TL;DR: Patterns of genetic variants assayed from paternally, maternALLY, and biparentally inherited genetic systems reveal that extensive hybridization of the two subspecies is part of the ancestry of Northern Indian, peripheral European, and almost all African cattle breeds.
Abstract: Genetics has the potential to provide a novel layer of information pertaining to the origins and relationships of domestic cattle. While it is important not to overstate the power of archeological inference from genetic data, some previously widespread conjectures are inevitably contradicted with the addition of new information. Conjectures regarding domesticated cattle that fall into this category include a single domestication event with the development of Bos indicus breeds from earlier Bos taurus domesticates; the domestication of a third type of cattle in Africa having an intermediate morphology between the two taxa; and the special status of the Jersey breed as a European type with some exotic influences. In reality, a wideranging survey of the genetic variation of modern cattle reveals that they all derive from either zebu or taurine progenitors or are hybrids of the two. The quantitative divergence between Bos indicus and Bos taurus strongly supports a predomestic separation; that between African and European taurines also suggests genetic input from native aurochsen populations on each continent. Patterns of genetic variants assayed from paternally, maternally, and biparentally inherited genetic systems reveal that extensive hybridization of the two subspecies is part of the ancestry of Northern Indian, peripheral European, and almost all African cattle breeds. In Africa, which is the most extensive hybrid zone, the sexual asymmetry of the process of zebu introgression into native taurine breeds is strikingly evident. © 1998 Wiley-Liss, Inc.
TL;DR: The initial evolutionary approach to resource conservation has contrasted predictions generated from optimal foraging theory with predictions based on assumptions of conservation, and this work uses evolutionary theory to understand human foraging behavior.
Abstract: Many important aspects of human nature revolve around common problems associated with acquiring, defending, and distributing resources. It is increasingly evident that foraging constraints,1 as well as competition, and cooperation with conspecifics,2–4 selected for increased intelligence in primates. The cognitive tools for responding to risk and reward likely evolved in a context of resource acquisition and distribution during our evolutionary past, in the so-called environment of evolutionary adaptedness.5–7 The cognitive skills required for cooperative hunting, such as cheater and cooperator detectors,8 and especially the accounting required for fitnessenhancing harvesting, distribution, and consumption (e.g., time discounting9), are reflected in behaviors we exhibit today. Our evolved psychological disposition to respond economically is likely derived from past ecological relationships with the beasts our hominid ancestors preyed on and the organisms that preyed on hominids. It is not hard to imagine that many human social and political institutions have developed as solutions to complex economic production and distribution problems.10 Thus, it not surprising that human evolutionary ecology borrows from economic theory9,11–15 and, increasingly, vice versa.16–20 It is in this context that the topic of resource conservation has been the focus of theoretical development and hypothesis-testing by evolutionary ecologists. As I will show, the initial evolutionary approach to resource conservation has contrasted predictions generated from optimal foraging theory with predictions based on assumptions of conservation. This work Michael S. Alvard is Assistant Professor of Anthropology at the State University of New York at Buffalo. His research uses evolutionary theory to understand human foraging behavior. He has done field work with the Piro and Machiguenga Indians and the Wana of Upland Sulawesi, Indonesia. He is currently researching cooperative hunting among a group of whale hunters in the Lesser Sunda Islands, Nusa Tenggara, Indonesia. E-mail: alvard@acsu.buffalo.edu
TL;DR: An animal's life history can be summarized by key variables that account for its life course from conception to death, and the rather obvious fact that such variables differ from species to species and from individual to individual has been the subject of much interest since the late 1960s.
Abstract: An animal's life history can be summarized by key variables that account for its life course from conception to death. Biological parameters that are of interest relate to reproductive effort and developmental rates (e.g., gestation length, neonatal weight, prenatal and postnatal growth rates, weaning age, and weaning weight) and the rate of reproduction (e.g., age at first and last reproduction, interbirth interval, the number of offspring per litter, birth rate, and the intrinsic rate of natural increase [rmax]). The rather obvious fact that such variables differ from species to species and from individual to individual has been the subject of much interest since the late 1960s, following the observation that species seem to be arranged in a spectrum that ranges from small animals that breed rapidly and develop early, have many young per litter, and have short lives, to large animals that breed slowly and develop late, have few young per litter, and have long lives. © 1998 Wiley-Liss, Inc.
TL;DR: A series of CT based studies has already yielded new insights into character differences between fossil hominid species, and these techniques offer noninvasive tools for visualization of inaccessible regions of the skeleton, computer‐assisted reconstruction of fragmentary fossil specimens, and morphometric or biomechanical analysis of data derived from CT images.
Abstract: Paleoanthropologists are confronted by a steadily growing number of fossil specimens exhibiting diversity in both apparent morphology and state of preservation. Studying this material to answer phylogenetic and functional questions requires extensive qualitative assessment accompanied by quantitative evaluation of large volumes of data. Over the past decade, major new developments in both respects have been made possible through the advent of medical imaging technologies, most notably computer tomography (CT), and through concomitant progress in computer graphics technology. In paleoanthropology, these techniques offer noninvasive tools for visualization of inaccessible regions of the skeleton, computer-assisted reconstruction of fragmentary fossil specimens, and morphometric or biomechanical analysis of data derived from CT images. A series of CT based studies has already yielded new insights into character differences between fossil hominid species. © 1998 Wiley-Liss, Inc.
TL;DR: If accurate, these dates require significant changes in current ideas not just about the initial colonization of Australia, but about the entire chronology of human evolution in the late Middle and early Upper Pleistocene, and there are good reasons to be skeptical.
Abstract: Until recently, archeologists have generally agreed that modern humans arrived on Australia and its continental islands, New Guinea and Tasmania (collectively, Greater Australia), about 35,000 to 40,000 years ago,1 a time range that is consistent with evidence of their first appearance elsewhere in the Old World well outside Africa.2,3 Over the past decade, however, this consensus has been eroded, first by dates of 50,000 to 60,000 years from two sites in Arnhem Land4,5 and then, dramatically, by dates of 116,000 to 176,000 years from a third site on the eastern margin of the nearby Kimberley region.6 If accurate, these dates require significant changes in current ideas, not just about the initial colonization of Australia, but about the entire chronology of human evolution in the late Middle and early Upper Pleistocene. Either fully modern humans were present well outside Africa at a surprisingly early date or the behavioral capabilities long thought to be uniquely theirs were also associated, at least to some degree, with other hominids. Deciding whether these dates are accurate and associated with definite evidence of human activity thus becomes critically important. We think there are good reasons to be skeptical, not only on the basis of the dates and their alleged associations, but because of their mismatch with established sequences, both in Greater Australia and elsewhere. Until these issues are resolved, adjusting the broader global picture to accommodate these early dates is premature. © 1998 Wiley-Liss, Inc.
TL;DR: The recent discovery of early primate remains has led to an enormous literature on these fossils and an increased interest in the study of anthropoid origins, which allows a better understanding of the early evolutionary history of the group of mammals from which the authors evolved.
Abstract: The suborder Anthropoidea, also called simians or simiiforms, contains New and Old World monkeys, apes, and humans. The recent discovery of early primate remains has led to the production of an enormous literature on these fossils and an increased interest in the study of anthropoid origins. Research on these early anthropoids allows a better understanding of the early evolutionary history of the group of mammals from which we evolved. © 1998 Wiley‐Liss, Inc.
TL;DR: Population genetic theory provides the hope that through analyses of genetic data we will gain insight into the history of populations as mentioned in this paper, however, there remains a wide gap between the available theory and data; too often we fail to draw firm conclusions because our interpretation of analytic results requires that we make myriad assumptions about our data.
Abstract: While molecular evolutionists may be fascinated by the features and history of a particular gene or DNA segment, evolutionary anthropologists are often more interested in the activities and history of groups of people. We may want to know, for instance, when and where humans have migrated, how much exchange between groups has taken place, and how population sizes have changed. Population genetic theory provides the hope that through analyses of genetic data we will gain insight into the history of populations. Genetic data from extant human populations are now accruing at a remarkable rate. We might, therefore, expect to have answers in hand. There remains, however, a wide gap between the available theory and data; too often we fail to draw firm conclusions because our interpretation of analytic results requires that we make myriad assumptions about our data. In any one instance, these assumptions might include estimates of mutation rate, mutational mechanism, population sizes, the role that natural selection has played, and the rate of migration among groups. Often these assumptions are implicit, invisible to most. How, then, are we to make any progress? © 1998 Wiley-Liss, Inc.
TL;DR: The conventional K‐Ar technique has given way to 40Ar/39Ar dating as the method of preference, which is not only more precise and accurate when dating ideal materials, but also permits excellent ages to be obtained from situations that often stymie the conventional K-Ar technique, such as dating of contaminated tuffs and altered rocks.
Abstract: The potassium-argon (K-Ar) dating method has been widely used over the past 40 years to provide radioisotopic age control of hominid/hominoid evolutionary time scales. The wide appeal of the technique to paleoanthropology and archeology has been, in part, a result of its broad time range of applicability, from materials as young as a few thousand years old to an essentially unbounded upper age limit. Another reason for its appeal is the many geological circumstances in which datable materials are found. Beginning about two decades ago and accelerating into this decade, however, the conventional K-Ar technique has given way to 40Ar/39Ar dating as the method of preference. This technique is not only more precise and accurate when dating ideal materials, but also permits excellent ages to be obtained from situations that often stymie the conventional K-Ar technique, such as dating of contaminated tuffs and altered rocks. © 1998 Wiley-Liss, Inc.
TL;DR: The story of human evolution is described in detail in this article, where Johanson and Jablonski present a modern synthesis of human origins, and discuss contemporary issues in human evolution.
Abstract: Getting Here: The Story of Human Evolution
By WW Howells (1997). Washington: Compass Press. 266 pp. $19.95 (cloth) ISBN 0-929590-16-3. $36.95 (paper) ISBN 0-929590-17-1.
From Lucy to Language
By DC Johanson and B Edgar. Principal Photography by David Brill (1996). New York: Simon and Schuster, 272 pp. $50.00 (cloth) ISBN 0-684-81023-9.
Reconstructing Human Origins: A Modern Synthesis
By GC Conroy (1997). New York: WW. Norton.xii + 557 pp. $43.13 (paper) ISBN 0-393-97042-6.
Humans Before Humanity
By R Foley (1997) Oxford: Blackwell Publishers.vii + 248 pp. $21.95 paper ISBN 0-631-20528-4.
Contemporary Issues in Human Evolution
By E Meickle, FC Howell and N Jablonski (1996) Wattis Symposium Series in Anthropology. Nina G. Jablonski, Series Editor. California Academy of Sciences Memoir 21. San Francisco: California Academy of Sciences.viii+193pp $35.00 cloth ISBN 0-940228-45-9. © 1998 Wiley-Liss, Inc.
TL;DR: The centerpiece of the BioVisualization Lab is a high-resolution laser digitizer, a point-scanning instrument that generates an array of x, y, z coordinates that record the geometry of an object as it spins or translates below the laser beam.
Abstract: C omputer-based visualization is revolutionizing many fields of science by suggesting new questions , creating new forms of data, presenting new ways to publish results, and increasing accessibility to the public through the World Wide Web. There are numerous examples of the alluring power of this three-dimensional (3-D) technology as it can objectively capture meaningful information and produce novel images of scientific specimens. The Smithsonian BioVisualization Lab was established to produce research quality digital (virtual) specimens for scientific study and education. One of our principle objectives has been to adopt a technology that could produce highly accurate digital files for taking exact measurements and for creating accurate computer-generated images of specimens. Researchers at the BioVisualization Lab have worked in collaboration with the Digital Research and Imaging Lab of the Mississippi State University to develop approaches and to establish In-ternet access that will enable others to share work and specimens on-line. The beginning of the Smithsonian BioVisualization Lab grew out of proof-of-concept experimentation with laser scanners and digital data conducted at other facilities in the late 1980s. The apparatus for magnetic resonance imaging and scanners for computer-assisted tomography and positron emission tomography are among the better-known examples of the types of tools used to create 3-D imagery (for reviews, see Hartwig and Sadler, 1 and Dean. 2) These tools have been shown to have interesting applications to anthropology, such as the reconstruction of skulls from multiple pieces. 3 The centerpiece of the BioVisualiza-tion Lab is a high-resolution laser digitizer, a point-scanning instrument. The device generates an array of x, y, z coordinates that record the geometry of an object as it spins or translates below the laser beam. The data array becomes a series of parallel contour lines that are later translated into a more refined polygonal geometry. Data collection is automated by setting various machine parameters such as point interval and laser beam focus, and by setting protocols that define a target window and calibrate the vertical distance between a point on the target surface and the laser head. When the laser fires, it triggers an internal reading of each point in an x, y plane. The reflection of the laser beam is simultaneously registered on a pair of charge-coupled device (CCD) sensors to enable triangulation of the height measurement (z coordinate value) of each datum. As the coordinate points record the geometry of the object's surface, software is used …
TL;DR: Function, Phylogeny and Fossils: Miocene Hominoid Evolution and Adaptations, and The Evolution of Western Eurasian Neogene Mammal Faunas, © 1998 Wiley-Liss, Inc.
Abstract: Function, Phylogeny and Fossils: Miocene Hominoid Evolution and Adaptations
Begun, DG, Ward, CV, Rose, MD eds. (1997). New York: Plenum Press. xii + 424 pp. ISBN 0-306-45457-2. $120.00 (cloth).
The Evolution of Western Eurasian Neogene Mammal Faunas
Bernor, RL, Fahlbusch, V, Mittman, H (eds). (1996). New York: Columbia University Press. ix + 487 pp. ISBN 0-231-08246-0. $92.00 (cloth). © 1998 Wiley-Liss, Inc.