Adaptation and niche construction in human prehistory: a case study from the southern Scandinavian Late Glacial

Evidence for hunter-gatherer impacts on raven diet and ecology in the Gravettian of Southern Moravia

The earlier Gravettian of Southern Moravia-the Pavlovian-is notable for the many raven bones (Corvus corax) documented in its faunal assemblages. On the basis of the rich zooarchaeological and settlement data from the Pavlovian, previous work suggested that common ravens were attracted by human domestic activities and subsequently captured by Pavlovian people, presumably for feathers and perhaps food. Here, we report independent δ15N, δ13C and δ34S stable isotope data obtained from 12 adult ravens from the Pavlovian key sites of Předmostí I, Pavlov I and Dolní Věstonice I to test this idea. We show that Pavlovian ravens regularly fed on larger herbivores and especially mammoths, aligning in feeding preferences with contemporaneous Gravettian foragers. We argue that opportunistic-generalist ravens were encouraged by human settlement and carcass provisioning. Our data may thus provide surprisingly early evidence for incipient synanthropism among Palaeolithic ravens. We suggest that anthropogenic manipulation of carrion supply dynamics furnished unique contexts for the emergence of human-oriented animal behaviours, in turn promoting novel human foraging opportunities-dynamics which are therefore important for understanding early hunter-gatherer ecosystem impacts.

Gradistics: An underappreciated dimension in evolutionary space

The growth of complexity is an unsolved and underappreciated problem. We consider possible causes of this growth, hypotheses testing, molecular mechanisms, complexity measures, cases of simplification, and significance for biomedicine. We focus on a general ability of regulation, which is based on the growing information storage and processing capacities, as the main proxy of complexity. Natural selection is indifferent to complexity. However, complexification can be inferred from the same first principle, on which natural selection is founded. Natural selection depends on potentially unlimited reproduction under limited environmental conditions. Because of the demographic pressure, the simple ecological niches become fulfilled and diversified (due to species splitting and divergence). Diversification increases complexity of biocenoses. After the filling and diversification of simple niches, the more complex niches can arise. This is the 'atomic orbitals' (AO) model. Complexity has many shortcomings but it has an advantage. This advantage is ability to regulatory adaptation, including behavioral, formed in the evolution by means of genetic adaptation. Regulatory adaptation is much faster than genetic one because it is based on the information previously accumulated via genetic adaptation and learning. Regulatory adaptation further increases complexity of biocenoses. This is the 'regulatory advantage' (RA) model. The comparison of both models allows testable predictions. We focus on the animal evolution because of the appearance of higher regulatory level (nervous system), which is absent in other lineages, and relevance to humans (including biomedical aspects).

Collapse of the mammoth-steppe in central Yukon as revealed by ancient environmental DNA

The temporal and spatial coarseness of megafaunal fossil records complicates attempts to to disentangle the relative impacts of climate change, ecosystem restructuring, and human activities associated with the Late Quaternary extinctions. Advances in the extraction and identification of ancient DNA that was shed into the environment and preserved for millennia in sediment now provides a way to augment discontinuous palaeontological assemblages. Here, we present a 30,000-year sedimentary ancient DNA (sedaDNA) record derived from loessal permafrost silts in the Klondike region of Yukon, Canada. We observe a substantial turnover in ecosystem composition between 13,500 and 10,000 calendar years ago with the rise of woody shrubs and the disappearance of the mammoth-steppe (steppe-tundra) ecosystem. We also identify a lingering signal of Equus sp. (North American horse) and Mammuthus primigenius (woolly mammoth) at multiple sites persisting thousands of years after their supposed extinction from the fossil record.

Why do we pick similar mates, or do we?

Humans often mate with those resembling themselves, a phenomenon described as positive assortative mating (PAM). The causes of this attract broad interest, but there is little agreement on the topic. This may be because empirical studies and reviews sometimes focus on just a few explanations, often based on disciplinary conventions. This review presents an interdisciplinary conceptual framework on the causes of PAM in humans, drawing on human and non-human biology, the social sciences, and the humanities. Viewing causality holistically, we first discuss the proximate causes (i.e. the 'how') of PAM, considering three mechanisms: stratification, convergence and mate choice. We also outline methods to control for confounders when studying mate choice. We then discuss ultimate explanations (i.e. 'the why') for PAM, including adaptive and non-adaptive processes. We conclude by suggesting a focus on interdisciplinarity in future research.

Operationalizing niche construction theory with stone tools

One of the greatest difficulties with evolutionary approaches in the study of stone tools (lithics) has been finding a mechanism for tying culture and biology in a way that preserves human agency and operates at scales that are visible in the archaeological record. The concept of niche construction, whereby organisms actively construct their environments and change the conditions for selection, could provide a solution to this problem. In this review, we evaluate the utility of niche construction theory (NCT) for stone tool archaeology. We apply NCT to lithics both as part of the "extended phenotype" and as residuals or precipitates of other niche-constructing activities, suggesting ways in which archaeologists can employ niche construction feedbacks to generate testable hypotheses about stone tool use. Finally, we conclude that, as far as its applicability to lithic archaeology, NCT compares favorably to other prominent evolutionary approaches, such as human behavioral ecology and dual-inheritance theory.

Genes, culture, and the human niche: An overview

The sharp distinction between biological traits and culturally based traits, which had long been standard in evolutionary approaches to behavior, was blurred in the early 1980s by mathematical models that allowed a co-dependent evolution of genetic transmission and cultural information. Niche-construction theory has since added another contrast to standard evolutionary theory, in that it views niche construction as a cause of evolutionary change rather than simply a product of selection. While offering a new understanding of the coevolution of genes, culture, and human behavior, niche-construction models also invoke multivariate causality, which require multiple time series to resolve. The empirical challenge lies in obtaining time-series data on causal pathways involved in the coevolution of genes, culture, and behavior. This is a significant issue in archeology, where time series are often sparse and causal behaviors are represented only by proxies in the material record.

Materiality, Agency and Evolution of Lithic Technology: an Integrated Perspective for Palaeolithic Archaeology

Considerations of materiality and object-oriented approaches have greatly influenced the development of archaeological theory in recent years. Yet, Palaeolithic archaeology has been slow in incorporating this emerging body of scholarship and exploring its bearing on the human deep past. This paper probes into the potential of materiality theory to clarify the material dynamics of the Plio-Pleistocene and seeks to re-articulate the debate on the evolution of our species with materiality discourses in archaeology and the humanities more broadly. We argue that the signature temporalities and geospatial scales of observation provided by the Palaeolithic record offer unique opportunities to examine the active role of material things, objects, artefacts and technologies in the emergence, stabilisation and transformation of hominin lifeworlds and the accretion of long-term trajectories of material culture change. We map three axes of human-thing relations-ecological, technical and evolutionary-and deploy a range of case studies from the literature to show that a critical re-assessment of material agency not only discloses novel insights and questions, but can also refine what we already know about the human deep past. Our exploration underscores the benefits of de-centring human behaviour and intentionality and demonstrates that materiality lends itself as a productive nexus of exchange and mutual inspiration for diverging schools and research interests in Palaeolithic archaeology. An integrated object-oriented perspective calls attention to the human condition as a product of millennial-scale human-thing co-adaptation, in the course of which hominins, artefacts and technologies continuously influenced and co-created each other.

Disequilibrium, Adaptation, and the Norse Settlement of Greenland

There is increasing evidence to suggest that arctic cultures and ecosystems have followed non-linear responses to climate change. Norse Scandinavian farmers introduced agriculture to sub-arctic Greenland in the late tenth century, creating synanthropic landscapes and utilising seasonally abundant marine and terrestrial resources. Using a niche-construction framework and data from recent survey work, studies of diet, and regional-scale climate proxies we examine the potential mismatch between this imported agricultural niche and the constraints of the environment from the tenth to the fifteenth centuries. We argue that landscape modification conformed the Norse to a Scandinavian style of agriculture throughout settlement, structuring and limiting the efficacy of seasonal hunting strategies. Recent climate data provide evidence of sustained cooling from the mid thirteenth century and climate variation from the early fifteenth century. Archaeological evidence suggests that the Norse made incremental adjustments to the changing sub-arctic environment, but were limited by cultural adaptations made in past environments.

Long term effects of climate on human adaptation in the middle Gila River Valley, Arizona, America

The Hohokam, an irrigation-based society in the American South West, used the river valleys of the Salt and Gila Rivers between 500 and 1500 AD to grow their crops. Such irrigated crops are linking human agency, water sources and the general natural environment. In order to grow crops, water available through rain and river flows needs to be diverted to land where the plants are grown. With a focus on the Gila River, this paper uses the potential harvest of maize (a main Hohokam crop) as a proxy for evaluating the influence of natural water availability and climatic changes on irrigation options for maize. Available climate variables derived from tree-ring proxies are downscaled. These downscaled data are used as input for a crop growth model for the entire sequence of Hohokam occupation along the Gila River. The results of the crop model are used to discuss the potential influence of climatic variability on Hohokam irrigation and society. The results will show that climatic change alone cannot be used as an explanation for developments in Hohokam irrigation. Societal development resulting in growing population and extensive irrigation systems increasing pressure on water sources over time would have been a key factor to include to understand Hohokam society between 500 and 1500 AD.

Phylogenetic analysis shows that Neolithic slate plaques from the southwestern Iberian Peninsula are not genealogical recording systems

Prehistoric material culture proposed to be symbolic in nature has been the object of considerable archaeological work from diverse theoretical perspectives, yet rarely are methodological tools used to test the interpretations. The lack of testing is often justified by invoking the opinion that the slippery nature of past human symbolism cannot easily be tackled by the scientific method. One such case, from the southwestern Iberian Peninsula, involves engraved stone plaques from megalithic funerary monuments dating ca. 3,500-2,750 B.C. (calibrated age). One widely accepted proposal is that the plaques are ancient mnemonic devices that record genealogies. The analysis reported here demonstrates that this is not the case, even when the most supportive data and techniques are used. Rather, we suspect there was a common ideological background to the use of plaques that overlay the southwestern Iberian Peninsula, with little or no geographic patterning. This would entail a cultural system in which plaque design was based on a fundamental core idea, with a number of mutable and variable elements surrounding it.

Evolution of lactase persistence: an example of human niche construction

Niche construction is the process by which organisms construct important components of their local environment in ways that introduce novel selection pressures. Lactase persistence is one of the clearest examples of niche construction in humans. Lactase is the enzyme responsible for the digestion of the milk sugar lactose and its production decreases after the weaning phase in most mammals, including most humans. Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation (-13910*T) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle East. Current estimates for the age of lactase persistence-associated alleles bracket those for the origins of animal domestication and the culturally transmitted practice of dairying. We report new data on the distribution of -13910*T and summarize genetic studies on the diversity of lactase persistence worldwide. We review relevant archaeological data and describe three simulation studies that have shed light on the evolution of this trait in Europe. These studies illustrate how genetic and archaeological information can be integrated to bring new insights to the origins and spread of lactase persistence. Finally, we discuss possible improvements to these models.

Human niche construction in interdisciplinary focus

Niche construction is an endogenous causal process in evolution, reciprocal to the causal process of natural selection. It works by adding ecological inheritance, comprising the inheritance of natural selection pressures previously modified by niche construction, to genetic inheritance in evolution. Human niche construction modifies selection pressures in environments in ways that affect both human evolution, and the evolution of other species. Human ecological inheritance is exceptionally potent because it includes the social transmission and inheritance of cultural knowledge, and material culture. Human genetic inheritance in combination with human cultural inheritance thus provides a basis for gene-culture coevolution, and multivariate dynamics in cultural evolution. Niche construction theory potentially integrates the biological and social aspects of the human sciences. We elaborate on these processes, and provide brief introductions to each of the papers published in this theme issue.

General patterns of niche construction and the management of 'wild' plant and animal resources by small-scale pre-industrial societies

Niche construction efforts by small-scale human societies that involve 'wild' species of plants and animals are organized into a set of six general categories based on the shared characteristics of the target species and similar patterns of human management and manipulation: (i) general modification of vegetation communities, (ii) broadcast sowing of wild annuals, (iii) transplantation of perennial fruit-bearing species, (iv) in-place encouragement of economically important perennials, (v) transplantation and in-place encouragement of perennial root crops, and (vi) landscape modification to increase prey abundance in specific locations. Case study examples, mostly drawn from North America, are presented for each of the six general categories of human niche construction. These empirically documented categories of ecosystem engineering form the basis for a predictive model that outlines potential general principles and commonalities in how small-scale human societies worldwide have modified and manipulated their 'natural' landscapes throughout the Holocene.