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Evolutionary theories of ageing and senescence provide a framework that allows to understand why apparently maladaptive senescent phenotypes are observed under natural conditions, despite the fact that natural selection should, at first sight, be opposed to mechanisms that lead to the deterioration of bodily functions with advancing age. While ageing has been shown in the wild and has been explored under artificial laboratory conditions, sex-dependent pattern were not considered in detail. The aim of this thesis is to draw from the existing theories of sexual selection, life-history and sexual conflict, to get a more complete understanding of sex-specific effects on ageing patterns. The organism I use in all experiments is the Black Field Cricket Teleogryllus commodus. To test for sex-specific demographic ageing patterns in the wild, I use a capture-mark-recapture study and analyse the resulting data with a new method that combines classic capture-recapture models with a recent mathematical technique that allows to estimate survival probabilities from recapture data for which the date of births of animals are unknown (Chapter 2). I test for reproductive and demographic ageing under near-natural conditions in field enclosure (Chapter 3). In laboratory based manipulation studies I estimate the effect of a) different juvenile and adult diets on the ageing patterns (Chapter 4), and b) a reduction of the ability to spend energy on calling and how this relates to lifespan (Chapter 5). In a half-sib breeding design I measure early and late reproductive effort in males and in females to estimate genetic correlations and thereby test for antagonistic pleiotropy between early and late components and between males and females. The studies in the wild indicate that Teleogryllus commodus senesce under natural conditions and that males have overall higher mortality rates. Females, not males, show reproductive ageing under both enclosure and laboratory conditions. The genetic architecture revealed no discord between male and female fitness components and there was no evidence for antagonistic pleiotropy between early and late fitness components. These results show that a) it is important to include male measures of reproductive effort in ageing studies and that b) the field of ageing research should benefit a lot from incorporating sexual selection, life-history and sexual conflict theory.

ReFace (Reality Enhancement Facial Approximation by Computational Estimation) is a prototype facial approximation software program developed by the Federal Bureau of Investigation (FBI) in conjunction with GE Global Research. The prototype extrapolates an “approximation” of a face from a skull using a database of computed tomography (CT) scans of living individuals. The test set consisted of CT scans of 53 articulated human skulls from the William M. Bass Donated Skeletal Collection and the William M. Bass Forensic Skeletal Collection, which are curated at the University of Tennessee in Knoxville. Through the Federal Bureau of Investigation’s Visiting Scientist Program, an educational opportunity administered by the Oak Ridge Institute of Science and Education (ORISE), the researcher conducted an independent validation of this software in two phases. Phase 1 tested and evaluated the software performance, resulting in improvements to the software and the development of standardized protocol for articulation, packaging, and preparation of human skulls for CT scans. Phase 2 validated the accuracy of the software in the production of facial approximations from human skulls using face pools and resemblance ratings. In Phase 2, computerized facial approximations were visually compared with antemortem photographs by four participant groups (N = 103). Ten test subjects of European ancestry (six females and four males) were selected for a photographic validation by face pool and resemblance rating validation tests. Participants were asked to choose the face pool photograph that most closely resembled the facial approximation produced by ReFace. In the second test, the same volunteers were asked to rate (on a scale of 1 to 5) how closely ReFace facial approximations of target subjects resembled an antemortem photograph. In the Face Pool Validation Test, nine out of ten target subjects were correctly identified above random chance, and the frequency distribution was statistically above chance expectations for nine out of ten target subjects (p < .01). The mean hit rate for all subjects was 24% (10% above random chance). There were no significant differences in the hit rates between male participants (67%) and females participants (33%), or between participant groups. All participants were non-experts. Male target subjects received higher numbers of correct responses than female target subjects. The overall ratings for the Resemblance Rating Validation Test were 13% none, 24% slight, 22% approximate, 25% close, and 16% strong. The majority of subjects were rated as close resemblance (six subjects), strong resemblance (one subject), approximate resemblance (one subject), and slight resemblance (one subject). The foil comparison received an equal number of ratings for no resemblance (30.5%) and slight resemblance (30.5%).

Determining sex from skeletal remains is important in forensic and archaeological settings. Though using the pelvis to determine sex is ideal, often remains are fragmentary or incomplete, requiring sex to be estimated from other skeletal elements. Many individual bones have been studied to evaluate sexual dimorphism and the extent to which they can be used to determine sex of an unknown individual. However, sexual dimorphism in the vertebral column has only been examined to a limited extent. The purpose of this study is to examine the extent of sexual dimorphism throughout the entire vertebral column and, if present, to establish a method by which sex can be determined from any given vertebra, even if the exact vertebral number is not known. A total of 16 different measurements were taken on the vertebrae from a sample of 119 individuals from the William M. Bass Skeletal Collection. Given the small representation of African American individuals in the collection, only individuals of European descent were considered in this study. Since possible effects of aging were to be considered, equal numbers of males and females were randomly selected and matched for age groups. First MANOVA analyses were performed on each vertebrae and vertebral grouping, i.e. cervical C3-C7, thoracic, lumbar, and vertebral column C3-L5, to determine if each was significant for sex for each measurement taken. A stepwise analysis and then discriminant function analysis was performed to select the most sexually dimorphic measurements for each vertebra or vertebral grouping and equations were developed to allow sex to be determined from an unknown individual for each vertebra, or if the vertebral number is not known, from the vertebral grouping.

Proefschrift - Amsterdam.

Inaug.-diss.--München. / Curriculum vitae. "Verseichnis der benützten literatur": p. 31-32.

Thesis (Ph. D.)--University of Chicago, Department of Anthropology, June 2001. / Includes bibliographical references. Also available on the Internet.

<p>The discovery of hundreds of fossil hominin remains from the Dinaledi Chamber of Rising Star cave in South Africa included dozens of immature elements attributed to multiple individuals. Some of these elements are amongst the most complete in the Dinaledi assemblage, but have not yet been fully studied. Thorough examination of these immature remains is important because they can provide a more complete understanding of the morphology of the Dinaledi hominins, facilitate an assessment of morphological development in the assemblage, and allow for direct comparisons with other immature fossil hominins. This dissertation focuses on the most diagnostic specimens of the immature lower limb (with reference to the immature upper limb and the mature sample) from the site and utilizes a comparative approach examining developmental variation in the proximal femur and limb proportions of extinct and extant ape species to discern the ontogenetic basis of the adult Dinaledi hominin form.</p><p>The first portion of this dissertation addresses the development of proximal femoral shape in an ontogenetic series of femora from the Dinaledi hominins, modern humans, chimpanzees, and gorillas. Results indicate that the development of proximal diaphyseal shape and neck-shaft angle are conserved within Homininae, but that neck shape may develop differently in bipeds than non-bipeds. The absolute shape of the femoral neck, however, markedly differs between the Dinaledi sample and modern humans, with greater anteroposterior constriction of the neck in the former, potentially due to increased superioinferior loading of the region associated with differing locomotor kinematics between species. </p><p>The second portion of this dissertation investigates the relative proportions of the immature Dinaledi lower limb. To date, the only lower limb long bone preserving the entire diaphysis and an articular surface to be recovered from the chamber, is the immature tibia, U.W. 101-1070. The length of this specimen was evaluated relative to the size of the preserved joint surface in an ontogenetic context and was found to be relatively long compared to other fossil hominins and even modern humans. The humero-tibial proportions of the immature Dinaledi hominins were found to be outside of the range of chimpanzees and gorillas, but comparable to modern humans and the immature Homo erectus specimen KNM-ER 15000. Together, these findings demonstrate that, with respect to relative lower limb length, the Dinaledi hominins are highly derived. </p><p>The mixture of primitive (australopith-like) and derived (Homo-like) features of the Dinaledi hominins identified in this dissertation are consistent with other early work on the assemblage and imply that the Dinaledi chamber contains Plio-Pleistocene hominins. Given small brain and predicted body sizes for the Dinaledi hominins, the results presented here suggest that relative limb elongation may have occurred prior to increases in brain and body size during hominin evolution and that bipedal energetic efficiency may have been the primary locus of selection. </p> / Dissertation

<p> The universality and importance of cooking both culturally and biologically is well established. Knowing when, where, and how in the archaeological record human groups began employing this practice can help answer questions concerning the timing and mechanism of both behavioral and anatomical changes in hominins. Identifying cooking in the archaeological record, however, is a complex taphonomic issue. When, where, and how hominins started controlling fire in the past is a greatly debated topic. Analyses of microscopic traces in soil and on bone may offer new lines of taphonomic evidence needed to demonstrate a specific use for fire. Specific cooking practices may also leave behind specific traces of macro-, micro-, faunal, and artifactual evidence. Previous research showed no change in the mineral component of human bone when boiled. To test the hypothesis that crystallinity changes also do not occur under low intensity thermal alteration, domestic pig limb bones were boiled for varying lengths of time. This study determined that even at longer periods of boiling, no observable change is observed in the crystallinity of the hydroxyapatite of bone. What was noted, however, was the existence of patina fractures on fleshed bone when boiled to certain lengths of time. Continued study of this novel observation may offer new insights into what degree of thermal intensity is needed for certain macroscopic observations and what micro- or primary structural properties of bone account for them. Other methods that examine the microstructure of bone may be able to detect changes that occur with low intensity thermal alteration that are unrelated to the state of the hydroxyapatite minerals. Further investigation is needed to understand which methods are best able, if possible, to identify differences that occur in bone that undergoes different diagenetic processes (i.e. weathering vs. low intensity thermal alteration vs. high intensity thermal alteration). Such investigations can illuminate how fire was utilized in the past.</p>

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