Download or read book Cranial Morphology Variation and Integration in Homo Sapiens written by Whitney B Reiner and published by . This book was released on 2017 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract Cranial Morphology, Variation, and Integration in Homo sapiens by Whitney Brooke Reiner, Doctor of Philosophy in Integrative Biology University of California, Berkeley Professor Leslea Hlusko, Chair Herein I present three separate manuscripts pertaining to cranial morphology, variation, and integration in humans. The first manuscript introduces a newly recovered partial calvaria, OH 83, from the upper Ndutu Beds of Olduvai Gorge, Tanzania. I present the geological context of its discovery, a comparative analysis of its morphology, and place OH 83 within the context of our current understanding of the origins and evolution of Homo sapiens. The morphology of OH 83 was analyzed using quantitative and qualitative data from penecontemporaneous fossils and the W.W. Howells modern human craniometric dataset. OH 83 is geologically dated to ca. 60-32 ka. Its morphology is indicative of an early modern human, falling at the low end of the range of variation for post-orbital cranial breadth, the high end of the range for bifrontal breadth, and near average in frontal length. There have been numerous attempts to use cranial anatomy to define the species Homo sapiens and identify it in the fossil record. These efforts have not met wide agreement by the scientific community due, in part, to the mosaic patterns of cranial variation represented by the fossils. The variable, mosaic pattern of trait expression in the crania of Middle and Late Pleistocene fossils implies that morphological modernity did not occur at once. However, OH 83 demonstrates that by ca. 60-32 ka modern humans in Africa included individuals that are at the fairly small and gracile range of modern human variation. In the second manuscript I provide craniometric data from Early Period (ca. 5000 B.P.) hunter-gatherers from the Sacramento Valley and the San Francisco Bay Area that represent some of the earliest indigenous Californians. I compare these data to the published worldwide human craniometric data set to provide perspectives on the range of human variation and the inter-relatedness of that variation. I collected 76 cranial measurements and five indices from 59 adult crania collected using a three-dimensional (3D) digitizer (MicroScribe G2, Immersion Corporation), following published protocols associated with the comparative data set. I conducted two sets of analyses exploring the range of variation, and calculating correlations. My analyses reveal that the Early Period Native Californians extends the known range of variation for 20 measurements. For six of the measurements, the smaller end of the range is extended, while the higher end of the range is extended for 14 measurements. For Native Americans, the Early Period Native Californians extend the range for 53 measurements, four of which are extended at both ends of the range. Correlation matrices for these data suggest the face is an integrated region of the cranium across modern humans, but specific patterns of correlation within and between regions of the cranium varied across populations. The early Native Californian crania exhibited the strongest overall correlations, differing significantly from the other samples (Mantel test, p
Download or read book The Evolution of Modern Human Diversity written by Marta Mirazón Lahr and published by Cambridge University Press. This book was released on 1996-05-30 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigates the two main theories of how and where humans evolved.
Download or read book Patterns of Morphological Integration in Modern Human Crania written by Adam Kolatorowicz and published by . This book was released on 2015 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project examines patterns of phenotypic integration in modern human cranial morphology using geometric morphometric methods. It is theoretically based in the functional paradigm of craniofacial growth and morphological integration. The hypotheses being addressed are: 1) cranial form is influenced by secular trends, sex, and phylogenetic history of the population and 2) integration patterns wherein the basicranium is the keystone feature best explains the relationships among in cranial modules. Geometric morphometric methods were used to collect and analyze three-dimensional coordinate data of 152 endocranial and ectocranial landmarks from 391 anatomically modern human crania. These crania are derived from temporally historic and recent groups in the United States spanning both sexes and across several ancestral groups. Landmark data were subjected to generalized Procrustes analysis and then areas of shape variation were identified via principal components analysis of shape coordinates. Discriminant function analysis and canonical variate analysis identified regions that can be used to separate groups. Temporal period, ancestry, and sex all have significant effects on mean shape. Age-at-death accounts for a small proportion of the total variation. Modern individuals have higher, narrower vaults with highly arched palates and historic individuals have short, wider vaults with shallower palates. The forehead, brow ridges, and cheek shape were closely associated with sexual dimorphism. Variation in both the vault and face allowed for separation of ancestral groups with concomitant inferior movement of the anterior basicranium in the median plane. Three major hypotheses of modularity were tested based on functional demands of cranial modules, functional-developmental fields, and the basicranium. Comparing covariance structures of partitions of landmark subsets revealed that the cranium is more integrated when considering functional demands of cranial components origins of cranial components and is less modular when considering developmental origins. Special sensory modules are the most independent units in the cranium. Depending on the definition of cranial modules, results may be quite different and not comparable across studies. This project integrates anthropology, evolutionary anatomy, and developmental biology. It makes a significant contribution to our understanding of integration patterns in the modern human cranium and highlights differences among theoretical frameworks of integration. The findings can be used for individual identification in medicolegal contexts and clinical applications for surgical treatment of craniofacial-related disorders and injuries. Future research will include examining patterns of morphological integration in non-human primates.
Download or read book Landscape Phenomics of the Human Face written by Scott Kirkland and published by . This book was released on 2021 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of human cranial morphology has a long and contentious history. This study is the first large scale analysis of ecoregion specific human cranial modularity and integration. It utilizes an analysis of morphometric craniofacial variation and ecoregion affinity to better understand the environmental contribution to biological shape. This study tested three hypotheses. First, that there was variation in craniofacial shape that was linked to an individual's ecoregion. Second, that there were ecoregion specific patterns of cranial modularity. And third, that the patterns of cranial integration (or the level of covariation between any two modules) were also associated with an individual's ecoregion, and that different environments would result in different patterns of modular dependence and independence. Three-dimensional scans of 298 human crania were collected from museums, representing four higher level ecoregions and 11 lower-level ecoregions. Each cranium was mapped and placed within two hierarchical ecoregions. By examining ecoregions, instead of individual climatic variables, this analysis gives a more complete picture of how the environment is influencing cranial variation. Modules, or relatively independent morphological regions of the crania, were identified and their level of integration was assessed for every ecoregion. Modular integration is an analysis of the relative strength of the covariation between any two modules, and previous research theorized that changes in integration reflected changes in modular independence during development (Bastir and Rosas, 2005; Hall, 2005; Raff, 1996). The variation in strength between modules, both intrapopulation and interpopulation, were assessed and various explanations were explored. This analysis found that each ecoregion exhibited significantly different craniofacial shape from one another. Patterns of integration were also variable by ecoregion, suggesting that the ecological shape variation observed was solidified early in development. This study also identified the presence of a nasal module in each ecoregion. Overall, the findings of this study demonstrate that human crania are variable by ecoregion and that environmental conditions have led to ecoregion specific patterns of cranial modular integration.
Download or read book Morphological Integration of the Cranium During Ontogeny in Homo Sapiens and Pan Troglodytes written by Joshua Michael Polanski and published by . This book was released on 2009 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Evolution of the Human Head written by Daniel E. Lieberman and published by Harvard University Press. This book was released on 2011-01-03 with total page 769 pages. Available in PDF, EPUB and Kindle. Book excerpt: In one sense, human heads function much like those of other mammals. We use them to chew, smell, swallow, think, hear, and so on. But, in other respects, the human head is quite unusual. Unlike other animals, even our great ape cousins, our heads are short and wide, very big brained, snoutless, largely furless, and perched on a short, nearly vertical neck. Daniel E. Lieberman sets out to explain how the human head works, and why our heads evolved in this peculiarly human way. Exhaustively researched and years in the making, this innovative book documents how the many components of the head function, how they evolved since we diverged from the apes, and how they interact in diverse ways both functionally and developmentally, causing them to be highly integrated. This integration not only permits the head’s many units to accommodate each other as they grow and work, but also facilitates evolutionary change. Lieberman shows how, when, and why the major transformations evident in the evolution of the human head occurred. The special way the head is integrated, Lieberman argues, made it possible for a few developmental shifts to have had widespread effects on craniofacial growth, yet still permit the head to function exquisitely. This is the first book to explore in depth what happened in human evolution by integrating principles of development and functional morphology with the hominin fossil record. The Evolution of the Human Head will permanently change the study of human evolution and has widespread ramifications for thinking about other branches of evolutionary biology.
Download or read book The Human Skull written by Spencer Lee Rogers and published by Charles C. Thomas Publisher. This book was released on 1984 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ancestry and Sex in Human Crania written by Robert W. Mann and published by Charles C Thomas Publisher. This book was released on 2021-08-11 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: This atlas consists of 29 male and 21 female crania and is intended to serve as a reference source of documented-identity crania in the Mann-Labrash Osteology Collection at the John A. Burns School of Medicine (JABSOM) of the University of Hawaii, Manoa. It is intended to add to our knowledge of the complexity and range of cranial variation and to provide examples based on contemporary known-identity individuals. Large color photographs are provided for researchers to reference when estimating ancestry, sex, and, to a limited extent, age. This atlas increases our comparative reference samples and diversity to include individuals of Asian and Pacific Islander ancestry. Most crania in this atlas are presented using six anatomical views: anterior, right lateral, left lateral, inferior (basilar), superior, and posterior (occipital) in the Frankfort horizontal plane. A superior view of each mandible is included to provide the reader with size and shape features of the teeth and bone. Additional photos are included to highlight other features such as dental morphology and anatomical variants. Many photographs are labeled to identify specific features, while others are not, leaving interpretation to the reader. Figure captions reflect the author’s opinion but are intended to allow readers to interpret features for themselves and draw their own conclusions based on the photographs of each cranium. The photographs are intended to provide readers with the most holistic and integrated perspective of each feature. Each feature is viewed as part of the whole without requiring the reader to place them along a fixed continuum or sequence based on size or shape. Photographs also allow readers to examine each feature as an integrated piece of the “puzzle.”
Download or read book Species Species Concepts and Primate Evolution written by William H. Kimbel and published by Springer Science & Business Media. This book was released on 2013-12-18 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: A world of categones devmd of spirit waits for life to return. Saul Bellow, Humboldt's Gift The stock-in-trade of communicating hypotheses about the historical path of evolution is a graphical representation called a phylogenetic tree. In most such graphics, pairs of branches diverge from other branches, successively marching across abstract time toward the present. To each branch is tied a tag with a name, a binominal symbol that functions as does the name given to an individual human being. On phylogenetic trees the names symbolize species. What exactly do these names signify? What kind of information is communicated when we claim to have knowledge of the following types? "Tetonius mathewzi was ancestral to Pseudotetonius ambiguus. " "The sample of fossils attributed to Homo habzlis is too variable to contain only one species. " "Interbreeding populations of savanna baboons all belong to Papio anubis. " "Hylobates lar and H. pileatus interbreed in zones of geographic overlap. " While there is nearly universal agreement that the notion of the speczes is fundamental to our understanding of how evolution works, there is a very wide range of opinion on the conceptual content and meaning of such particular statements regarding species. This is because, oddly enough, evolutionary biolo gists are quite far from agreement on what a species is, how it attains this status, and what role it plays in evolution over the long term.
Download or read book Skull Shapes and the Map written by William White Howells and published by Peabody Museum of Archaeology and Ethnology, Harvard University Publications Department. This book was released on 1989 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this sequel to his Cranial Variation in Man, William White Howells surveys present-day regional skull shapes by a uniform method, examining the nature and degree of cranial differences discernible between recent Homo sapiens populations around the world.
Download or read book Examination of Shape Variation of the Calcaneus Navicular and Talus in Homo Sapiens Gorilla Gorilla and Pan Troglodytes written by Nicole L. Robinson and published by . This book was released on 2018 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analyses of morphological integration among primates commonly focus on relationships between the face, braincase and base of the skull, as well as the upper and lower dentition, and the within portions of the post-cranial skeleton. Despite the prominence of these studies, the associations between the bones of the foot and their articular surfaces have largely been ignored among primates, even though the foot demonstrates high degrees of variation and modification. This variation offers an ideal opportunity to study the relationship between morphology and locomotion. Because the talus, calcaneus and navicular act together to stabilize the foot in locomotion and form a direct interface with the substrate, they comprise a complex structural unit, and the matching articular surfaces should be tightly integrated. However, preliminary results suggest there is no difference in the magnitude or pattern of integration within and between bones. While there is no systematic difference in the magnitude of correlations distinguishing articular surfaces from non-articular parts of the bones, the pattern of covariation is itself correlated across species for each bone, with correlations among measurements of articular surfaces consistently positive. This suggests at the least that there are shared patterns of integration across species.
Download or read book Morphological Integration written by Everett C. Olson and published by University of Chicago Press. This book was released on 1999-10 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite recent advances in genetics, development, anatomy, systematics, and morphometrics, the synthesis of ideas and research agenda put forth in the classic Morphological Integration remains remarkably fresh, timely, and relevant. Pioneers in reexamining morphology, Everett Olson and Robert Miller were among the first to explore the concept of the integrated organism in both living and extinct populations. In a new foreword and afterword, biologists Barry Chernoff and Paul Magwene summarize the landmark achievements made by Olson and Miller and bring matters discussed in the book up to date, suggest new methods, and accentuate the importance of continued research in morphological integration. Everett C. Olson was a professor at the University of Chicago and at the University of California, Los Angeles. He was a former president of the Society of Vertebrate Paleontology. Robert L. Miller was associate professor of geology at the University of Chicago, associate scientist in marine geology at the Woods Hole Oceanographic Institution, and a member of the board of editors of the Journal of Geology.
Download or read book A Study Through Skull Morphology on the Diversity of Holocene African Populations in a Historical Perspective written by Isabelle Ribot and published by British Archaeological Reports Limited. This book was released on 2011 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of the present research is to explore through skull morphology some potential sources of biological diversity within sub-Saharan Africa, such as: geography and especially history, in relation to large-scale population movements (expansion of Bantu-speakers). Therefore, through various statistical analyses, morphological variation was re-evaluated within modern sub-Saharan African populations, using a very large modern human sample and a set of metric variables related to the cranium and mandible. In the same way, morphological patterns through time were also traced, focusing on various Later Stone Age and Iron Age populations, originating in particular from strategic areas of various influences. In Chapter 2 after having briefly introduced both geographical and historical backgrounds of sub-Saharan Africa, the dispersal of Bantu-speakers, a very long-term and large-scale phenomenon, which initiated since the Early Iron Age (c. 1,000 BC) is presented in more depth. In Chapter 3, after a detailed presentation of the populations and variables under study, a preliminary analysis of inter- and intra-observer errors is presented. In chapter 4, various factors (geography, sex and ecology) are tested as a source of modern diversity. Chapter 5 looks a the effects of historical factors on skull morphology through both modern and past African diversity. Following the conclusion the author presents an extensive assemblage of Appendices (sites and datasets).
Download or read book The Influence of Climate and Diet on Human Skull Shape Form and Size written by David Charles Katz and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Late Pleistocene dispersal from Africa, mostly to cooler climates, and the Holocene emergence of agricultural subsistence economies, are two of the more remarkable developments in Homo sapiens’ evolutionary history. A substantial body of research relates directional evolution in global human skull shape and form to the influence of these changes in lifeway. Quantifying these morphological transformations in anything other than broad, correlational terms has, however, proven challenging. The problem is largely methodological. The tendency for populations that share more of an evolutionary past to more closely resemble each other explains a substantial proportion of cranial differentiation among human groups. These effects of population history and structure can obscure the influence of a directional predictor. They must be accounted for statistically if the influence of climate and diet on diversity in the human skull is to be accurately quantified. In studies of recent human skeletal diversity, partial Mantel tests are perhaps the most common method for partitioning structured and directional effects. Partial Mantel tests simplify the comparison among classes of observations—shape, genetic relationships, climate, etc.—by transforming each to a matrix of pairwise distances between populations. The method then tests for correlations (technically, partial correlations) between the distance matrices. The focus is on whether a consistent relationship exists between, say, cranial and diet distances. Distances are practically the natural units of genetic relationships. On a phylogenetic tree, the total distance along branches separating two closely related groups is expected to be shorter than the branch lengths separating remotely related groups. In contrast, the information cost of transforming phenotypic observations to pairwise distances can be very high. This is particularly true for landmark-based observations of shape and form. The beauty of statistical shape analysis is its potential to both quantify and concretely represent morphological variation. When shape data are transformed to distances, the most striking feature of the observations, their shape, is irretrievably lost. Thus, a partial Mantel may speak to whether human cranial shape and diet (distances) are correlated, but not how cranial shape evolved in response to subsistence strategy. Yet it is the latter inquiry that is central to evaluating biological and evolutionary importance. Here, I evaluate the influence of climate and diet on human skull shape and form using a recently-developed mixed model for high-dimensional observations. Mixed models were originally developed specifically to account for dependence in structured samples, and have a long theoretical and applied history in quantitative genetic studies of pedigreed populations. Most importantly, mixed models produce effect size estimates and confidence intervals in the observations’ original units of measurement. In this study, the numerical effect size estimates are translated into two- and three-dimensional shape and form contrasts—intuitive, biologically meaningful representations of how human skull morphology varies with climate and subsistence conditions. The most prominent changes in skull shape and form across the agricultural transition include a generally less massive mandible, smaller anterior temporalis muscle (as delineated by landmarks along the superior temporal line), taller mandibular coronoid process, narrower mandibular ramus, and perhaps a posterior shift of the dentition. These changes are largely consistent with the view that novel food processing technologies and the less resistant physical properties of agricultural foods—cereals, dairy—decreased masticatory demands in farming populations relative to hunter-gatherers. Intriguingly, many of the differences between forager and farmer masticatory morphology are simple extensions of shape transformations that distinguish Homo sapiens from its nearest relatives. This may indicate evolutionary constraints on the evolution of the human masticatory apparatus, or similarities in the direction of evolutionary forces acting on the human skull at macro- and micro-evolutionary timescales. Shape and form changes associated with human migration to colder climates include a larger cranium, more globular cranial vault, and a more vertical, taller face, including a taller nasal aperture. A larger, rounder cranium fits the basic empirical patterns characterized in Bergmann’s and Allen’s Rules, most often hypothesized to relate thermoregulatory demands. Increased facial and nasal height have been interpreted as external manifestations of an internal nasal cavity reconfigured to better warm and moisten inspired air in cold climates. The climate results are consistent with the proposition that distinct evolutionary dynamics govern temperature effects in the face and vault. Changes in vault shape and cranial size (which is primarily vault size) over the temperature range in the sample are reasonably well characterized by a single slope coefficient. In contrast, facial shape and size effects are small across warm and moderate environments, and accelerate in extreme cold. In the pages that follow, Chapter 1 provides a more in-depth introduction to the research. Chapter 2 is a literature review. The materials situate the evidence for climate and diet adaptations in the context of human population history, and review common methodological strategies for evaluating evolutionary questions of this nature. Chapter 3 explains mixed model approaches to estimating directional and structured effects in evolutionary samples. Chapter 4 uses a high-dimensional mixed model to evaluate climate effects on linear measurements of human skull form. Chapters 5 extends the mixed model to three-dimensional cranial and mandibular observations, quantifying both climate and diet effects. Chapter 6 offers concluding remarks.
Download or read book Cranial Shape Variation in Homo Erectus written by Karen L. Baab and published by . This book was released on 2007 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Anthropology of Modern Human Teeth written by G. Richard Scott and published by Cambridge University Press. This book was released on 2018-03-15 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: All humans share certain components of tooth structure, but show variation in size and morphology around this shared pattern. This book presents a worldwide synthesis of the global variation in tooth morphology in recent populations. Research has advanced on many fronts since the publication of the first edition, which has become a seminal work on the subject. This revised and updated edition introduces new ideas in dental genetics and ontogeny and summarizes major historical problems addressed by dental morphology. The detailed descriptions of 29 dental variables are fully updated with current data and include details of a new web-based application for using crown and root morphology to evaluate ancestry in forensic cases. A new chapter describes what constitutes a modern human dentition in the context of the hominin fossil record.
Download or read book Human Craniofacial Variation and Dental Anomalies An anthropological investigation into the relationship between human craniometric variation and the expression of orthodontic anomalies written by Joseph R Krecioch and published by diplom.de. This book was released on 2014-11-01 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dental anomalies of number, shape, and position are frequently analysed in the orthodontic and clinical literature but are rarely discussed in an anthropological or archaeological context. Dental anomalies and occlusal disorders are often hypothesised to be the result of a modern, urbanised lifestyle as a response to reduced masticatory stress and subsequent crowding of the dentition. This study of skulls from Classical to medieaval Macedonia and England examines the relationship between craniofacial variation and the expression of dental anomalies. Standard craniometric measurements were taken to estimate relative sizes of cranial functional complexes and determine whether or not, or to what extent, changes in the shape or size of these variables were associated with the expression of dental anomalies. Statistical analyses determined that the null hypothesis, that there is no relationship between craniometrics and dental anomalies, can be rejected. A number of dental anomalies were found to have a relationship with reduced sizes in cranial and masticatory elements, although dental crowding was not as significant a factor in masticatory complex reduction. A cause and effect relationship cannot be determined but the data presented here suggests that both heredity and environmental causes may be influential in the expression of dental anomalies.
