Domestication as a model system for niche construction theory

Niche Construction Theory (NCT) provides a powerful conceptual framework for understanding how and why humans and target species entered into domesticatory relationships that have transformed Earth’s biota, landforms, and atmosphere, and shaped the trajectory of human cultural development. NCT provides fresh perspective on how niche-constructing behaviors of humans and plants and animals promote co-evolutionary interactions that alter selection pressures and foster genetic responses in domesticates. It illuminates the role of niche-altering activities in bequeathing an ecological inheritance that perpetuates the co-evolutionary relationships leading to domestication, especially as it pertains to traditional ecological knowledge and the transmission of learned behaviors aimed at enhancing returns from local environments. NCT also provides insights into the contexts and mechanisms that promote cooperative interactions in both humans and target species needed to sustain niche-constructing activities, ensuring that these activities produce an ecological inheritance in which domesticates play an increasing role. A NCT perspective contributes to on-going debates in the social sciences over explanatory frameworks for domestication, in particular as they pertain to issues of reciprocal causation, co-evolution, and the role of human intentionality. Reciprocally, domestication provides a model system for evaluating on-going debates in evolutionary biology concerning the impact of niche construction, phenotypic plasticity, extra-genetic inheritance, and developmental bias in shaping the direction and tempo of evolutionary change.     

Runaway cultural niche construction

Cultural niche construction is a uniquely potent source of selection on human populations, and a major cause of recent human evolution. Previous theoretical analyses have not, however, explored the local effects of cultural niche construction. Here, we use spatially explicit coevolutionary models to investigate how cultural processes could drive selection on human genes by modifying local resources. We show that cultural learning, expressed in local niche construction, can trigger a process with dynamics that resemble runaway sexual selection. Under a broad range of conditions, cultural niche-constructing practices generate selection for gene-based traits and hitchhike to fixation through the build up of statistical associations between practice and trait. This process can occur even when the cultural practice is costly, or is subject to counteracting transmission biases, or the genetic trait is selected against. Under some conditions a secondary hitchhiking occurs, through which genetic variants that enhance the capability for cultural learning are also favoured by similar dynamics. We suggest that runaway cultural niche construction could have played an important role in human evolution, helping to explain why humans are simultaneously the species with the largest relative brain size, the most potent capacity for niche construction and the greatest reliance on culture.     

The evolutionary consequences of niche construction: a theoretical investigation using two-locus theory

This paper addresses the joint evolution of environment-altering (niche constructing) traits, and traits whose fitness depends on alterable sources of natural selection in environments. We explore the evolutionary consequences of this niche construction using a two-locus population genetic model. The novel conclusions are that niche construction can (1) cause evolutionary inertia and momentum, (2) lead to the fixation of otherwise deleterious alleles, (3) support stable polymorphisms where none are expected, (4) eliminate what would otherwise be stable polymorphisms, and (5) influence disequilibrium. The results suggest that the changes that organisms bring about in their niche can themselves be an important source of natural selection pressures, and imply that evolution may proceed in cycles of selection and niche construction.     

Homeostasis and the physiological dimension of niche construction theory in ecology and evolution

Niche construction theory (NCT) has been represented as a new and comprehensive theory of evolution, one that breaks the constraints imposed by the dominant and largely gene-selectionist standard evolutionary model that is presently mischaracterized as “Darwinian.” I will argue that NCT is not so much a new theory, as it is a fruitful readmission of a venerable physiological perspective on adaptation, selection and evolution. This perspective is closer in spirit and philosophy to the original (and richer) Darwinian idea developed by Darwin himself, and that animated much of the rich late nineteenth century debate about evolution, heredity, adaptation and development, a debate that was largely eclipsed by the early twentieth century emergence of the Neodarwinian synthesis. I will argue that a full realization of the promise of NCT turns on a full understanding of another intellectual revolution of the nineteenth century, Claude Bernard’s conception of homeostasis, a profound statement of the nature of life that has, through the twentieth century, come to be widely misunderstood and trivialized.     

The extended phenotype(s): a comparison with niche construction theory

While niche construction theory locates animal artefacts in their constructors’ environment, hence treating them as capable of exerting selective pressure on both the constructors and their descendants, the extended phenotype concept assimilates artefacts with their constructors’ genes. Analogous contrasts apply in the case of endoparasite and brood parasite genes influencing host behaviour. The explanatory power of these competing approaches are assessed by re-examining the core chapters of Richard Dawkins’ The Extended Phenotype. Because animal artefacts (chapter 11) have multiple evolutionary consequences for their constructors, the extra-body effects of a gene seemingly include feedback effects on multiple other genes, a result which is more consistent with niche construction theory than with selfish gene theory. In the case of endoparasite genes influencing host behaviour (chapter 12), Dawkins’ argument leaves out what appears to be the key explanatory component, namely the role of the host’s own bodily systems in making it possible for such genes to exist. For action at a distance (chapter 13), it is unclear whether the key genes have extended effects because they sit in the body of the manipulating organism, or alternatively do not have such effects because they sit in the body of its victim. It is argued that niche construction theory offers a superior explanation in all three cases, regardless of whether the extended phenotype concept is interpreted in selfish gene or selfish organism terms.     

Bryophytes and ecological niche theory

Classical niche theory, particularly in terms of competitive exclusion, does not appear to apply as well to bryophytes as to other organisms. Bryophyte communities, as well as those of other plants and of animals, can be thought of in terms of individual species each utilizing particular portions of various resource or habitat continua. Quantitative studies carried out since 1981, particularly those involving niche breadth and overlap, are reviewed. Special attention is given to niche diversification in Sphagnum , Splachnaceae, bryophyte communities in streams, and to ephemeral bryophyte communities. Some bryophyte communities appear to have equilibrium characteristics and to contain species with relatively narrow niche breadths and with no or only partial niche overlap. In many habitats, however, bryophyte communites have non-equilibrium characteristics and diversification of species in microhabitats is opportunistic. Do any bryophyte communities persist long enough for complete saturation by species which have realized niches determined by competitive interactions? Recent studies indicate that this is the case for at least some Sphagnum communities, but that it is the exception not the rule for bryophytes.     

蜱螨概述

对节肢动物门蛛形纲蜱螨亚纲的分类地位、形态特征、分类系统、生态习性,并对与人类关系比较密切的若干重要类群作了简要介绍。     

An introduction to capnography

The aim of this article is to present an overview of the practical aspects of capnography and to define its uses and limitations. Modern rapid-response infrared CO₂ analyzers are able to follow changes in CO₂ concentrations within a single breath and have, therefore, gained wide clinical acceptance for respiratory monitoring and for studying aspects of respiratory control. Their use for the estimation of mean arterial CO₂ tensions is limited, however, to individuals with normal lungs during resting metabolic states. They also require careful calibration taking barometric and water vapor pressure into account. Commonly encountered technical problems in capnography are condensation of water vapor and mucus plugging in the sampling tubes as well as poor recordings as a result of faulty connections and electrical interference. These can be minimized through selection and careful setting up of the most appropriate equipment for prevailing conditions. Despite some marked limitations, capnography can be a valuable tool in the assessment of ventilatory state and some aspects of respiratory control.     

An introduction to the theory of NON-uniformity of hygrothermal constituent of the environment

Non-uniformity of the hygrothermal constituent of the environment (NUN) causes problems not only of hot workplaces in industry, but also in lightweight buildings, and air-conditioned and even ventilated buildings. It is almost impossible to avoid cold draughts, unilateral thermal radiation etc. in such situations. The theory and definition of NUN in space and in time, and NUN climatic (convective, radiant, perspiratory) and NUN conductive are described.     

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.     

Cultural niche construction in a metapopulation

Cultural niche construction is the process by which certain evolving cultural traits form a cultural niche that affects the evolution of other genetic and cultural traits [Laland, K., et al., 2001. Cultural niche construction and human evolution. J. Evol. Biol. 14, 22-33; Ihara, Y., Feldman, M., 2004. Cultural niche construction and the evolution of small family size. Theor. Popul. Biol. 65, 105-111]. In this study we focus on cultural niche construction in a metapopulation (a population of populations), where the frequency of one cultural trait (e.g. the level of education) determines the transmission rate of a second trait (e.g. the adoption of fertility reduction preferences) within and between populations. We formulate the Metapopulation Cultural Niche Construction (MPCNC) model by defining the cultural niche induced by the first trait as the construction of a social interaction network on which the second trait may percolate. Analysis of the model reveals dynamics that are markedly different from those observed in a single population, allowing, for example, different (or even opposing) dynamics in each population. In particular, this model can account for the puzzling phenomenon reported in previous studies [Bongaarts, J., Watkins, S., 1996. Social interactions and contemporary fertility transitions. Popul. Dev. Rev. 22 (4), 639-682] that the onset of the demographic transition in different countries occurred at ever lower levels of development.     

Cultural niche construction and human evolution

Organisms frequently choose, regulate, construct and destroy important components of their environments, in the process changing the selection pressures to which they and other organisms are exposed. We refer to these processes as niche construction. In humans, culture has greatly amplified our capacity for niche construction and our ability to modify selection pressures. We use gene‐culture coevolutionary models to explore the evolutionary consequences of culturally generated niche construction through human evolution. Our analysis suggests that where cultural traits are transmitted in an unbiased fashion from parent to offspring, cultural niche construction will have a similar effect to gene‐based niche construction. However, cultural transmission biases favouring particular cultural traits may either increase or reduce the range of parameter space over which niche construction has an impact, which means that niche construction with biased transmission will either have a much smaller or a much bigger effect than gene‐based niche construction. The analysis also reveals circumstances under which cultural transmission can overwhelm natural selection, accelerate the rate at which a favoured gene spreads, initiate novel evolutionary events and trigger hominid speciation. Because cultural processes typically operate faster than natural selection, cultural niche construction probably has more profound consequences than gene‐based niche construction, and is likely to have played an important role in human evolution.     

On the theory of niche overlap

The factors which are likely to limit niche overlap are studied for a class of idealized biological communities in which several species compete on a onedimensional continuum of resources, e.g., food size. Although the shape of the resource spectrum restricts the composition of possible equilibrium communities, and although this restriction is increasingly stringent as niche overlap increases, such considerations do not in principle put a limit to niche overlap. In analysing the stability of these equilibrium communities, two qualitatively different circumstances need be distinguished. In a strictly unvarying (deterministic) environment, stability sets no limit to the degree of overlap, short of complete congruence. However, in a randomly fluctuating (stochastic) environment, community stability requires that the average food sizes for species adjacent on the resource spectrum must differ by an amount roughly equal to the standard deviation in the food size taken by either individual species. This limit to species packing has a weak (logarithmic) dependence on the degree of environmental variance.This mathematical result is very robust, as is shown by considering, inter alia, a wide range of resource spectrum shapes, and a variety of shapes for the functions describing how the species utilize the resource. The effect of including additional resource dimensions is estimated.The general conclusion from the model is that there is an effective limit to niche overlap in the real world, and that this limit is insensitive to the degree of environmental fluctuation, unless it be very severe. This conclusion seems in accord with an increasing body of field data.     

民族昆虫学简介

民族昆虫学是研究在非工业化社会中人与昆虫关系的科学。民族昆虫学的研究内容包括 :昆虫的食用、药用、观赏 ,利用昆虫娱乐和装饰 ,有害昆虫防治 ,昆虫崇拜和关于昆虫的神化传说等。研究民族昆虫学的方法有查阅文献和实地调查 ,两种方法相互补充。中国有许多民族处于偏远封闭的环境里 ,研究和挖掘他们与昆虫的相对独特的关系 ,吸收其成功的昆虫利用或防治经验 ,对促进各民族间交流和发展具有重要意义