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Discover the most talked about and latest scientific content & concepts.

Journal: Journal of anthropological sciences = Rivista di antropologia : JASS / Istituto italiano di antropologia

153

Fire is a powerful natural force that can change landscapes extremely quickly. Hominins have harnessed this resource for their own purposes, with mechanistic and developmental physiological consequences. In addition, the use of fire has niche constructive effects, altering selective environments for genetic and cultural evolution. We review the record for hominin fire use in the Plio-Pleistocene, before considering the various functions for its use, and the resultant mechanistic and developmental consequences. We also adopt the niche construction framework to consider how the use of fire can modify selective environments, and thus have evolutionary consequences at genetic and cultural levels. The light that fire produces may influence photoperiodicity and alter hormonally-controlled bodily rhythms. Fire used for cooking could have extended the range of foods hominins were able to consume, and reduced digestion costs. This may have contributed to the expansion of the hominin brain and facial anatomy, influenced by a higher quality cooked diet. Fire may also have allowed dispersal into northern areas with much cooler climates than the hominin African origin, posing novel problems that affected diet and social behaviour.

Concepts: Genetics, Natural selection, Evolution, Nutrition, Biology, Anatomy, Human evolution, Cooking

152

Tracing the evolution of human culture through time is arguably one of the most controversial and complex scholarly endeavors, and a broad evolutionary analysis of how symbolic, linguistic, and cultural capacities emerged and developed in our species is lacking. Here we present a model that, in broad terms, aims to explain the evolution and portray the expansion of human cultural capacities (the EECC model), that can be used as a point of departure for further multidisciplinary discussion and more detailed investigation. The EECC model is designed to be flexible, and can be refined to accommodate future archaeological, paleoanthropological, genetic or evolutionary psychology/behavioral analyses and discoveries. Our proposed concept of cultural behavior differentiates between empirically traceable behavioral performances and behavioral capacities that are theoretical constructs. Based largely on archaeological data (the ‘black box’ that most directly opens up hominin cultural evolution), and on the extension of observable problem-solution distances, we identify eight grades of cultural capacity. Each of these grades is considered within evolutionary-biological and historical-social trajectories. Importantly, the model does not imply an inevitable progression, but focuses on expansion of cultural capacities based on the integration of earlier achievements. We conclude that there is not a single cultural capacity or a single set of abilities that enabled human culture; rather, several grades of cultural capacity in animals and hominins expanded during our evolution to shape who we are today.

Concepts: Culture, Linguistics, Anthropology, Cultural anthropology, Human evolution, Civilization, Archaeology, Structuralism

152

The importance of the Grimaldi complex of caves and rock shelters is twofold: scientific and historical. Scientifically, it is one of the major Upper Paleolithic sites, considering the variety of mobiliary and parietal art, the number of single and multiple burials and associated grave goods, and the abundant lithic and fauna remains. Historically, the documentation of activity that took place in this site starting from the second half of the 19 th century and the studies carried out on the materials that have been recovered in the decades between 1870s-1910s, provide instructive examples of methods and goals of Paleolithic archeology and anthropology of the epoch. This paper combines the scientific and the historic interest of the site through a chronicle of the events that took place during the period of the most sensational discoveries, i.e. beginning with the identification in 1872 of the first Upper Paleolithic burial and ending with the results of the excavations carried out in 1901 at Grotte des Enfants published in four volumes a few years later. The paper discusses early interpretations and modern views on the different findings and documents changes in perspectives and goals of paleoanthropological research in over a century, raising some of the major issues of contemporary Upper Paleolithic studies.

Concepts: Science, Anthropology, Social sciences, History, Paleolithic, Stone Age, Burial, Upper Paleolithic

152

The role of the brain in the somatic development, as well as in the establishment of the different variables of the life history pattern in vertebrates has been largely debated. Moreover, during the last thirty years, dental development has been used as a good proxy to infer different aspects of the life history in hominins, primarily due to the correlation that exists between age at first molar eruption and brain size in the order Primates. We review these questions using what is known about brain growth and maturation, dental development and life history pattern, mainly in Homo sapiens and Pan troglodytes. It has been assumed that the brain represents the pace-maker of our development. However, we consider that our particular phenotype is the result of a hierarchical genetic program modulated by epigenetic and environmental factors. The particular bauplan of any kind of organisms (e.g. primates) may explain the high correlation observed between different variables of its life history pattern, brain size or dental development. However, the correlation of these variables seems to be less reliable when dealing with low-rank taxonomical categories (i.e., species). We suggest that, while there is likely some relationship between the rate of somatic development and tooth development, our brain size and maturation (and, by extension, those of other species of the genus Homo) have derived towards a particular trajectory, with a unique pattern of prenatal and postnatal time and rate of growth and, particularly, with remarkable slow brain maturation. We suggest that extremely slow brain maturation could be a very recent acquisition of the last H. sapiens populations. Furthermore, our review of the literature suggests caution in drawing conclusions about aspects of the life history of the hominins from the information we can obtain from dental development in fossil specimens.

Concepts: Brain, Human, Species, Primate, Hominidae, Chimpanzee, Teeth, Human evolution

151

African archaic humans dated to around 1,0 Ma share morphological affinities with Homo ergaster and appear distinct in cranio-dental morphology from those of the Middle Pleistocene that are referred to Homo heidelbergensis. This observation suggests a taxonomic and phylogenetic discontinuity in Africa that ranges across the Matuyama/Brunhes reversal (780 ka). Yet, the fossil record between roughly 900 and 600 ka is notoriously poor. In this context, the Early Stone Age site of Gombore II, in the Melka Kunture formation (Upper Awash, Ethiopia), provides a privileged case-study. In the Acheulean layer of Gombore II, somewhat more recent than 875 ±10 ka, two large cranial fragments were discovered in 1973 and 1975 respectively: a partial left parietal (Melka Kunture 1) and a right portion of the frontal bone (Melka Kunture 2), which probably belonged to the same cranium. We present here the first detailed description and computer-assisted reconstruction of the morphology of the cranial vault pertaining to these fossil fragments. Our analysis suggest that the human fossil specimen from Gombore II fills a phenetic gap between Homo ergaster and Homo heidelbergensis. This appears in agreement with the chronology of such a partial cranial vault, which therefore represents at present one of the best available candidates (if any) for the origin of Homo heidelbergensis in Africa.

Concepts: Human, Africa, Skull, Human evolution, Homo erectus, Homo ergaster, Acheulean, Homo heidelbergensis

7

Based on our teaching experience in medicine and psychology degree programs, we examine different aspects of human evolution that can help students to understand how the human body and mind work and why they are vulnerable to certain diseases. Three main issues are discussed: 1) the necessity to consider not only the mechanisms, i.e. the “proximate causations”, implicated in biological processes but also why these mechanisms have evolved, i.e. the “ultimate causations” or “adaptive significance”, to understand the functioning and malfunctioning of human body and mind; 2) examples of how human vulnerabilities to disease are caused by phylogenetic constraints, evolutionary tradeoffs reflecting the combined actions of natural and sexual selection, and/or mismatch between past and present environment (i.e., evolution of the eye, teeth and diets, erect posture and their consequences); 3) human pair-bonding and parent-offspring relationships as the result of socio-sexual selection and evolutionary compromises between cooperation and conflict. These psychobiological mechanisms are interwoven with our brain developmental plasticity and the effects of culture in shaping our behavior and mind, and allow a better understanding of functional (normal) and dysfunctional (pathological) behaviors. Thus, because the study of human evolution offers a powerful framework for clinical practice and research, the curriculum studiorum of medical and psychology students should include evolutionary biology and human phylogeny.

Concepts: Psychology, Medicine, Natural selection, Evolution, Biology, Phylogenetics, Evolutionary psychology, Charles Darwin

1

In the current opinion paper, we provide a comparative perspective on specific aspects of primate empathic abilities, with particular emphasis on the mirror neuron system associated with mouth/face actions and expression. Mouth and faces can be very salient communicative classes of stimuli that allow an observer access to the emotional and physiological content of other individuals. We thus describe patterns of activations of neural populations related to observation and execution of specific mouth actions and emotional facial expressions in some species of monkeys and in humans. Particular attention is given to dynamics of face-to-face interactions in the early phases of development and to the differences in the anatomy of facial muscles among different species of primates. We hypothesize that increased complexity in social environments and patterns of social development have promoted specializations of facial musculature, behavioral repertoires related to production and recognition of facial emotional expression, and their neural correlates. In several primates, mirror circuits involving parietal-frontal regions, insular regions, cingulate cortices, and amygdala seem to support automatic forms of embodied empathy, which probably contribute to facial mimicry and behavioural synchrony. In humans these circuits interact with specific prefrontal and temporo-parietal cortical regions, which facilitates higher order cognitive functions such as cognitive empathy and mental state attribution. Our analysis thus suggests that the evolution of higher forms of empathy, such as mentalizing, is also linked to the coupling between the perceptual and motor system related to face processing, which may have undergone a process of exaptation during primate phylogeny.

Concepts: Psychology, Species, Neuroscience, Cognition, Primate, Empathy, Emotion, Mirror neuron

1

Although Linnaeus coined Homo sapiens in 1735, it was Blumenbach forty years later who provided the first morphological definition of the species. Since humans were not then allowed to be ante-Diluvian, his effort applied to the genus, as well. After the Feldhofer Grotto Neanderthal disproved this creationist notion, and human-fossil hunting became legitimate, new specimens were allocated either to sapiens or new species within Homo, or even to new species within new genera. Yet as these taxonomic acts reflected the morphological differences between specimens, they failed to address the question: What constitutes H. sapiens? When in 1950 Mayr collapsed all human fossils into Homo, he not only denied humans a diverse evolutionary past, he also shifted the key to identifying its species from morphology to geological age - a practice most paleoanthropologists still follow. Thus, for example, H. erectus is the species that preceded H. sapiens, and H. sapiens is the species into which H. erectus morphed. In order to deal with a growing morass of morphologically dissimilar specimens, the non-taxonomic terms “archaic” (AS) and “anatomically modern” (AMS) were introduced to distinguish between the earlier and later versions of H. sapiens, thereby making the species impossible to define. In attempting to disentangle fact from scenario, I begin from the beginning, trying to delineate features that may be distinctive of extant humans (ES), and then turning to the fossils that have been included in the species. With the exception of Upper Paleolithic humans - e.g. from Cro-Magnon, Dolni Vestonice, Mladeč - I argue that many specimens regarded as AMS, and all those deemed AS, are not H. sapiens. The features these AMS do share with ES suggest the existence of a sapiens clade. Further, restudy of near-recent fossils, especially from southwestern China (∼11-14.5 ka), reinforces what discoveries such as H. floresiensis indicate: “If it’s recent, it’s not necessarily H. sapiens”.

Concepts: Human, Evolution, Species, Hominidae, Neanderthal, Human evolution, Paleolithic, Homo erectus

0

Bipedalism is a defining trait of hominins, as all members of the clade are argued to possess at least some characters indicative of this unusual form of locomotion. Traditionally the evolution of bipedalism has been treated in a somewhat linear way. This has been challenged in the last decade or so, and in this paper I consider this view in light of the considerable new fossil hominin discoveries of the last few years. It is now apparent that there was even more locomotor diversity and experimentation across hominins than previously thought, and with the discovery of taxa such as H. floresiensis and H. naledi, that diversity continues well into the genus Homo. Based on these findings,we need to reevaluate how we define members of the genus Homo, at least when considering postcranial morphology, and accept that the evolution of hominin bipedalism was a complex and messy affair. It is within that context that the modern human form of bipedal locomotion emerged.

Concepts: Human, Species, Hominidae, Locomotion, Human evolution, Hominina, Hominid, Ardipithecus

0

The use of DNA sequences to elucidate the history of relationships of organisms is widespread, and focus on our species has been intense. This paper examines some simple aspects of using genetic information to analyze relationships within and amongst humans. Clonal markers (mtDNA and Y chromosomal DNA) have always shown a high degree of structure and robustness when analyzed for hierarchical structure. Results from genome wide phylogenetic structure in many organismal systems suggests instead that recombining genetic elements like the X chromosome and the autosomes will give conflicting information from genome region to genome region. In addition, the evolutionary signal from the different chromosomal regions will show a high degree of incongruence with each other, as do adjacent regions of chromosomes. This incongruence and lack of hierarchical structure is discussed in the context of what we know about human populations and the theoretical underpinnings of tree building based analysis of human populations.

Concepts: DNA, Gene, Cell, Human, Bacteria, Biology, Species, Chromosome