scholarly journals Dental tissue proportions in fossil orangutans from mainland Asia and Indonesia

2011 ◽  
Vol 1 (1) ◽  
pp. e1 ◽  
Author(s):  
Tanya M. Smith ◽  
Anne-Marie Bacon ◽  
Fabrice Demeter ◽  
Ottmar Kullmer ◽  
Kim Thuy Nguyen ◽  
...  
Keyword(s):  
Fossil Record ◽  
Homo Sapiens ◽  
Homo Erectus ◽  
Dental Tissue ◽  
Developmental Constraints ◽  
Enamel Thickness ◽  
Selective Pressures ◽  
The Past ◽  
Geometric Scaling ◽  
Dental Reduction

Orangutans (Pongo) are the only great ape genus with a substantial Pleistocene and Holocene fossil record, demonstrating a much larger geographic range than extant populations. In addition to having an extensive fossil record, Pongo shows several convergent morphological similarities with Homo, including a trend of dental reduction during the past million years. While studies have documented variation in dental tissue proportions among species of Homo, little is known about variation in enamel thickness within fossil orangutans. Here we assess dental tissue proportions, including conventional enamel thickness indices, in a large sample of fossil orangutan postcanine teeth from mainland Asia and Indonesia. We find few differences between regions, except for significantly lower average enamel thickness (AET) values in Indonesian mandibular first molars. Differences between fossil and extant orangutans are more marked, with fossil Pongo showing higher AET in most postcanine teeth. These differences are significant for maxillary and mandibular first molars. Fossil orangutans show higher AET than extant Pongo due to greater enamel cap areas, which exceed increases in enamel-dentine junction length (due to geometric scaling of areas and lengths for the AET index calculation). We also find greater dentine areas in fossil orangutans, but relative enamel thickness indices do not differ between fossil and extant taxa. When changes in dental tissue proportions between fossil and extant orangutans are compared with fossil and recent Homo sapiens, Pongo appears to show isometric reduction in enamel and dentine, while crown reduction in H. sapiens appears to be due to preferential loss of dentine. Disparate selective pressures or developmental constraints may underlie these patterns. Finally, the finding of moderately thick molar enamel in fossil orangutans may represent an additional convergent dental similarity with Homo erectus, complicating attempts to distinguish these taxa in mixed Asian faunas. 

scholarly journals Endostructural assessment of a hominin maxillary molar (StW 669) from Milner Hall, Sterkfontein, South Africa

2019 ◽  
Vol 115 (9/10) ◽  
Author(s):  
Bontle Mataboge ◽  
Amélie Beaudet ◽  
Jason L. Heaton ◽  
Travis R. Pickering ◽  
Dominic Stratford
Keyword(s):  
South Africa ◽  
Homo Sapiens ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Homo Erectus ◽  
Dental Tissue ◽  
Enamel Thickness ◽  
Homo Neanderthalensis ◽  
Morphometric Analyses ◽  
Maxillary Molar

The site of the Sterkfontein Caves, South Africa, is one of the richest early hominin fossil-bearing sites in Africa. Recent excavations in the Milner Hall locality have contributed to the discovery of new hominin specimens, including StW 669, a right permanent maxillary first molar (M1). StW 669 was excavated from the T1 deposits, which consist of a mixture of sediments from Members 2 and 5 of the Sterkfontein Formation. Accordingly, the deposits have the potential to contain remains of Australopithecus, Paranthropus and Homo. In this study, we employed micro-focus X-ray tomography in order to assess dental tissue proportions, enamel thickness distribution and enamel-dentine junction morphology as approaches to investigate the taxonomy of StW 669. We compare our results to those generated on the teeth of Australopithecus africanus, Paranthropus robustus, Homo erectus, Homo antecessor, Homo neanderthalensis and Homo sapiens. Our results suggest that StW 669 shares quantitative and qualitative affinities with M1s of Homo in terms of tissue proportions (i.e. two- and three-dimensional average and relative enamel thickness of 1.2–1.3 mm and 18.4, respectively) and enamel thickness distribution (i.e. thickest enamel on the lingual aspect of the protocone). However, data on the enamel-dentine junction morphology of StW 669 are inconclusive as to the tooth’s taxonomic affinities. Pending additional morphometric analyses, our studies of inner morphology of the crown of StW 669 support its attribution to Homo.

Introduction

2018 ◽  
Author(s):  
Gianfranco Pacchioni
Keyword(s):  
Industrial Revolution ◽  
Homo Sapiens ◽  
Modern Society ◽  
Full Time ◽  
Human Race ◽  
Hunter Gatherers ◽  
The Past ◽  
The World ◽  
The Universe ◽  
Radical Transformation

About 10,000 years ago, at the beginning of the agriculturalrevolution, on the whole earth lived between 5 and 8 million hunter-gatherers, all belonging to the Homo sapiens species. Five thousand years later, freed from the primary needs for survival, some belonging to that species enjoyed the privilege of devoting themselves to philosophical speculation and the search for transcendental truths. It was only in the past two hundred years, however, with the advent of the Industrial Revolution, that reaping nature’s secrets and answering fundamental questions posed by the Universe have become for many full-time activities, on the way to becoming a real profession. Today the number of scientists across the globe has reached and exceeded 10 million, that is, more than the whole human race 10,000 years ago. If growth continues at the current rate, in 2050 we will have 35 million people committed full-time to scientific research. With what consequences, it remains to be understood. For almost forty years I myself have been concerned with science in a continuing, direct, and passionate way. Today I perceive, along with many colleagues, especially of my generation, that things are evolving and have changed deeply, in ways unimaginable until a few years ago and, in some respects, not without danger. What has happened in the world of science in recent decades is more than likely a mirror of a similar and equally radical transformation taking place in modern society, particularly with the advent ...

“So Quick Bright Things Come to Confusion”

1987 ◽  
Vol 13 (2-3) ◽  
pp. 169-187
Author(s):  
Alexander Morgan Capron
Keyword(s):  
Homo Sapiens ◽  
Care Delivery ◽  
Well Being ◽  
Workplace Safety ◽  
Selective Abortion ◽  
Self Identity ◽  
The Past ◽  
Adverse Impacts ◽  
The Rich ◽  
Insurance Discrimination

In the past several decades, the problems facing those of us who labor in the vineyards of health policy and ethics have been the problems of success — first medicine's and then, though to a lesser extent, our own. By this I mean that it has been the remarkable fruits of biomedicine, from research to health care delivery, that have produced the rich harvest of ethical, social and legal issues that have drawn our, and society's, attention.In the basic science laboratory, scientists have developed means to splice pieces of DNA together, raising questions from workplace safety to the reengineering of homo sapiens. Of more immediate concern, tests for genetic susceptibility to disease in one's self and one's offspring have been developed, thereby generating questions about employment and insurance discrimination, selective abortion, and adverse impacts on self-identity and well-being.

Did Ground Cover Change Over Geologic Time?

2000 ◽  
Vol 6 ◽  
pp. 171-182 ◽  
Author(s):  
Ben A. LePage ◽  
Hermann W. Pfefferkorn
Keyword(s):  
Fossil Record ◽  
Ground Cover ◽  
The Other ◽  
Detailed Account ◽  
Geologic Time ◽  
The Past ◽  
Other Hand ◽  
Plant Fossil

When one hears the term “ground cover,” one immediately thinks of “grasses.” This perception is so deep-seated that paleobotanists even have been overheard to proclaim that “there was no ground cover before grasses.” Today grasses are so predominant in many environments that this perception is perpetuated easily. On the other hand, it is difficult to imagine the absence or lack of ground cover prior to the mid-Tertiary. We tested the hypothesis that different forms of ground cover existed in the past against examples from the Recent and the fossil record (Table 1). The Recent data were obtained from a large number of sources including those in the ecological, horticultural, and microbiological literature. Other data were derived from our knowledge of Precambrian life, sedimentology and paleosols, and the plant fossil record, especially in situ floras and fossil “monocultures.” Some of the data are original observations, but many others are from the literature. A detailed account of these results will be presented elsewhere (Pfefferkorn and LePage, in preparation).

scholarly journals The fossil record of whip spiders: the past of Amblypygi

PalZ ◽  
2021 ◽  
Author(s):  
Carolin Haug ◽  
Joachim T. Haug
Keyword(s):  
Fossil Record ◽  
3D Imaging ◽  
Three Dimensional ◽  
Dorsal Shield ◽  
Stereo Images ◽  
Geological Time ◽  
High Quality ◽  
The Past ◽  
Over Time

AbstractWhip spiders (Amblypygi), as their name suggests, resemble spiders (Araneae) in some aspects, but differ from them by their heart-shaped (prosomal) dorsal shield, their prominent grasping pedipalps, and their subsequent elongate pair of feeler appendages. The oldest possible occurrences of whip spiders, represented by cuticle fragments, date back to the Devonian (c. 385 mya), but (almost) complete fossils are known from the Carboniferous (c. 300 mya) onwards. The fossils include specimens preserved on slabs or in nodules (Carboniferous, Cretaceous) as well as specimens preserved in amber (Cretaceous, Eocene, Miocene). We review here all fossil whip spider specimens, figure most of them as interpretative drawings or with high-quality photographs including 3D imaging (stereo images) to make the three-dimensional relief of the specimens visible. Furthermore, we amend the list by two new specimens (resulting in 37 in total). The fossil specimens as well as modern whip spiders were measured to analyse possible changes in morphology over time. In general, the shield appears to have become relatively broader and the pedipalps and walking appendages have become more elongate over geological time. The morphological details are discussed in an evolutionary framework and in comparison with results from earlier studies.

scholarly journals Recent origin of low trabecular bone density in modern humans

2014 ◽  
Vol 112 (2) ◽  
pp. 366-371 ◽  
Author(s):  
Habiba Chirchir ◽  
Tracy L. Kivell ◽  
Christopher B. Ruff ◽  
Jean-Jacques Hublin ◽  
Kristian J. Carlson ◽  
...  
Keyword(s):  
Body Size ◽  
Trabecular Bone ◽  
Homo Sapiens ◽  
Modern Human ◽  
Homo Erectus ◽  
Lower Limbs ◽  
Modern Humans ◽  
Human Skeleton ◽  
Trabecular Density ◽  
Fossil Hominins

Humans are unique, compared with our closest living relatives (chimpanzees) and early fossil hominins, in having an enlarged body size and lower limb joint surfaces in combination with a relatively gracile skeleton (i.e., lower bone mass for our body size). Some analyses have observed that in at least a few anatomical regions modern humans today appear to have relatively low trabecular density, but little is known about how that density varies throughout the human skeleton and across species or how and when the present trabecular patterns emerged over the course of human evolution. Here, we test the hypotheses that (i) recent modern humans have low trabecular density throughout the upper and lower limbs compared with other primate taxa and (ii) the reduction in trabecular density first occurred in early Homo erectus, consistent with the shift toward a modern human locomotor anatomy, or more recently in concert with diaphyseal gracilization in Holocene humans. We used peripheral quantitative CT and microtomography to measure trabecular bone of limb epiphyses (long bone articular ends) in modern humans and chimpanzees and in fossil hominins attributed to Australopithecus africanus, Paranthropus robustus/early Homo from Swartkrans, Homo neanderthalensis, and early Homo sapiens. Results show that only recent modern humans have low trabecular density throughout the limb joints. Extinct hominins, including pre-Holocene Homo sapiens, retain the high levels seen in nonhuman primates. Thus, the low trabecular density of the recent modern human skeleton evolved late in our evolutionary history, potentially resulting from increased sedentism and reliance on technological and cultural innovations.

Bivalve systematics during the 20th century

2001 ◽  
Vol 75 (6) ◽  
pp. 1119-1127 ◽  
Author(s):  
Jay A. Schneider
Keyword(s):  
20Th Century ◽  
Molecular Systematics ◽  
Fossil Record ◽  
Evolutionary Biology ◽  
The Past ◽  
Invertebrate Paleontology

Over the past 75 years, the higher-level taxonomy of bivalves has received less attention than that of their fellow molluscs, gastropods. The publication of the bivalve volumes of the Treatise on Invertebrate Paleontology in 1969 was not followed by an explosion of study into the evolution of bivalves; rather, with only one or two exceptions, bivalve workers were noticeably absent from the cladistic and molecular revolutions that were taking place during the 1970s and 1980s, even as gastropods received considerable attention. Over the past ten years, cladistics and molecular systematics have begun to be applied to solve problems of bivalve evolutionary biology. These studies, most of which have been undertaken by paleontologists, have halted the stagnation in bivalve systematics. Bivalve systematics looks to have an exciting future, as the excellent fossil record of the Bivalvia will be used in conjunction with cladistics and molecular systematics to solve problems in not just bivalve evolution but evolutionary biology in general.

The Continuum of Psychosis and Its Genetic Origins

1990 ◽  
Vol 156 (6) ◽  
pp. 788-797 ◽  
Author(s):  
T. J. Crow
Keyword(s):  
Sex Chromosome ◽  
Homo Sapiens ◽  
Polymorphic Marker ◽  
Cerebral Dominance ◽  
Homo Erectus ◽  
Evolutionary Development ◽  
Pseudoautosomal Region ◽  
Sibling Pairs ◽  
Homo Habilis ◽  
Y Chromosomes

Attempts to draw a line of genetic demarcation between schizophrenic and affective illnesses have failed. It must be assumed that these diseases are genetically related. A post-mortem study has demonstrated that enlargement of the temporal horn of the lateral ventricle in schizophrenia but not in Alzheimer-type dementia is selective to the left side of the brain. This suggests that the gene for psychosis is the ‘cerebral dominance gene‘, the factor that determines the asymmetrical development of the human brain. That the psychosis gene is located in the pseudoautosomal region of the sex chromosomes is consistent with observations that sibling pairs with schizophrenia are more often than would be expected of the same sex and share alleles of a polymorphic marker at the short-arm telomeres of the X and Y chromosomes above chance expectation. That the cerebral dominance gene also is pseudoautosomal is suggested by the pattern of verbal and performance deficits associated with sex-chromosome aneuploidies. The psychoses may thus represent aberrations of a late evolutionary development underlying the recent and rapid increase in brain weight in the transition fromAustralopithecusthroughHomo habilisandHomo erectustoHomo sapiens.

scholarly journals Warfare, Ethics, Ethology: evolutionary fundamentals for conflict and cooperation

2020 ◽  
Author(s):  
Daniel Barreiros
Keyword(s):  
Phylogenetic Tree ◽  
Common Ancestor ◽  
Homo Sapiens ◽  
Social Ethics ◽  
Historical Narrative ◽  
Conflict And Cooperation ◽  
African Apes ◽  
The Past ◽  
Cognitive Capability ◽  
The Social

The aim of this article is to set a macro-historical narrative concerning the emergence of warfare and social ethics as symplesiomorphic features in the lineage of Homo sapiens. This means that these two behavioral aspects, representative of a very selected branch in the phylogenetic tree of the Primate order, are shared by the two lineages of great African apes that diverged from a common ancestor around six million years in the past, leading to extant humans and chimpanzees. Therefore, this article proposes an ethological understanding of warfare and social ethics, as both are innate to the social high-specialized modular mind present in the species of genera Pan and Homo. However behavioral restraints to intersocietal coalitionary violence seems to be an exclusive aspect of the transdominial modular cognition that characterizes modern humans. Thus, if in the evolutionary long durée, warfare and restrictions to intrasocial violence both appear to be ethologically common to humans and chimpanzees to a certain extent, an ethics of warfare - and, of course, the cognitive capability for intersocietal peace - seems to be distinctly human.

scholarly journals Human mitochondrial DNA diversity is compatible with the multiregional continuity theory of the origin of Homo sapiens

2021 ◽  
Vol 84 (4) ◽  
pp. 487-502
Author(s):  
Robert B. Eckhardt
Keyword(s):  
Homo Sapiens ◽  
Sequence Divergence ◽  
Homo Erectus ◽  
Gradual Transition ◽  
Complete Replacement ◽  
Human Mitochondrial Dna ◽  
Coalescence Time ◽  
Dna Diversity ◽  
Mtdna Sequence ◽  
Out Of Africa

Abstract Confidence intervals for estimates of human mtDNA sequence diversity, chimpanzee-human mtDNA sequence divergence, and the time of splitting of the pongid-hominid lineages are presented. Consistent with all the data used in estimating the coalescence time for human mitochondrial lineages to a common ancestral mitochondrion is a range of dates from less than 79,000 years ago to more than 1,139,000 years ago. Consequently, the hypothesis that a migration of modern humans (Homo sapiens) out of Africa in the range of 140,000 to 280,000 years ago resulted in the complete replacement, without genetic interchange, of earlier Eurasian hominid populations (Homo erectus) is but one of several possible interpretations of the mtDNA data. The data are also compatible with the hypothesis, suggested earlier and supported by fossil evidence, of a single, more ancient expansion of the range of Homo erectus from Africa, followed by a gradual transition to Homo sapiens in Europe, Asia, and Africa.

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