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PubMed2006

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 Evolution↗
PubMed1983

The cultural transmission of acquired variation: effects on genetic fitness.

In a cultural species individuals acquire some aspects of their phenotypes by imitating conspecifics. Presumably, cultural transmission has some adaptive function in such species. Some authors have suggested that one such function may be the ability to transmit phenotypes that have been modified by learning or some other form of phenotypic plasticity. To examine this hypothesis we have compared the genetic fitness of cultural and noncultural individuals in three different models. In each model the environment is assumed to be variable, either in space or time, and learning modifies each individual's phenotype so as to increase the individual's fitness in the local environment. Cultural individuals transmit the modified phenotype to their offspring, while noncultural individuals do not. The models are different in the following ways: two models assume a dichotomous phenotype, one in a temporally varying environment and one in a spatially varying environment; the third model assumes a quantitative phenotype in a temporally variable environment. The two models which assume a temporally varying environment yield similar results. Genetic transmission is favored in highly autocorrelated environments while cultural transmission in environments with intermediate autocorrelation. In the spatially varying model cultural transmission is always favored.

Biological Evolution↗
PubMed2002

Human eating behaviour in an evolutionary ecological context.

Present-day human eating behaviour in industrialised society is characterised by the consumption of high-energy-density diets and often unstructured feeding patterns, largely uncoupled from seasonal cycles of food availability. Broadly similar patterns of feeding are found among advantaged groups in economically-emerging and developing nations. Such patterns of feeding are consistent with the evolutionary ecological understanding of feeding behaviour of hominids ancestral to humans, in that human feeding adaptations are likely to have arisen in the context of resource seasonality in which diet choice for energy-dense and palatable foods would have been selected by way of foraging strategies for the maximisation of energy intake. One hallmark trait of human feeding behaviour, complex control of food availability, emerged with Homo erectus (1.9 x 10(6)-200000 years ago), who carried out this process by either increased meat eating or by cooking, or both. Another key trait of human eating behaviour is the symbolic use of food, which emerged with modern Homo sapiens (100000 years ago to the present) between 25000 and 12000 years ago. From this and subsequent social and economic transformations, including the origins of agriculture, humans have come to use food in increasingly elaborate symbolic ways, such that human eating has become increasingly structured socially and culturally in many different ways.

Animals↗
PubMed2004

At the crossroads of evolutionary computation and music: self-programming synthesizers, swarm orchestras and the origins of melody.

This paper introduces three approaches to using Evolutionary Computation (EC) in Music (namely, engineering, creative and musicological approaches) and discusses examples of representative systems that have been developed within the last decade, with emphasis on more recent and innovative works. We begin by reviewing engineering applications of EC in Music Technology such as Genetic Algorithms and Cellular Automata sound synthesis, followed by an introduction to applications where EC has been used to generate musical compositions. Next, we introduce ongoing research into EC models to study the origins of music and detail our own research work on modelling the evolution of melody.

Algorithms↗
PubMed2003

Darwin's legacy and the study of primate visual communication.

After Charles Darwin's The Expression of the Emotions in Man and Animals, published in 1872, we had to wait 60 years before the theme of animal expressions was picked up by another astute observer. In 1935, Nadezhda Ladygina-Kohts published a detailed comparison of the expressive behavior of a juvenile chimpanzee and of her own child. After Kohts, we had to wait until the 1960s for modern ethological analyses of primate facial and gestural communication. Again, the focus was on the chimpanzee, but ethograms on other primates appeared as well. Our understanding of the range of expressions in other primates is at present far more advanced than that in Darwin's time. A strong social component has been added: instead of focusing on the expressions per se, they are now often classified according to the social situations in which they typically occur. Initially, quantitative analyses were sequential (i.e., concerned with temporal associations between behavior patterns), and they avoided the language of emotions. I will discuss some of this early work, including my own on the communicative repertoire of the bonobo, a close relative of the chimpanzee (and ourselves). I will provide concrete examples to make the point that there is a much richer matrix of contexts possible than the common behavioral categories of aggression, sex, fear, play, and so on. Primate signaling is a form of negotiation, and previous classifications have ignored the specifics of what animals try to achieve with their exchanges. There is also increasing evidence for signal conventionalization in primates, especially the apes, in both captivity and the field. This process results in group-specific or "cultural" communication patterns.

Affect↗
PubMed2003

Morphological changes of Pseudomonas pseudoalcaligenes in response to temperature selection.

Adaptation to novel environments usually entails morphological changes. The cell morphology of six experimental populations of Pseudomonas pseudoalcaligenes and their common ancestor were examined with scanning electron microscopy (SEM). The six experimental populations were propagated under different temperatures for 10 months: three of them cultured at constant normal temperature (35 degrees C) forming the control group, and the other three cultured at incremental higher temperatures (from 41 degrees to 47 degrees C) as the HT group. SEM showed the deformed and elongated cells in the 6-h cultures of both ancestral and control populations at 45 degrees C, indicating that 45 degrees C is stressful for the ancestral and the control populations. In contrast, the HT populations retained normal cell shape in the 6-h cultures at both 35 degrees C and 45 degrees C. The mean cell volumes of control and HT populations increased 29% and 34%, respectively, relative to the ancestor at their respective thermal regimens, suggestion that the culturing conditions might favor larger cells.

Adaptation, Physiological↗
PubMed1999

Theoretical aspects of the mode of transmission in cultural inheritance.

This study investigates how evolutionary factors interact to determine the relative importance of vertical versus nonvertical mode of transmission in cultural inheritance. Simple mathematical models are provided to study the joint evolution of two cultural characters, one determining the viability and the fertility of individuals, and the other determining the vertical transmission rate of the first trait. Ordinary local stability analyses indicate that intrademic processes should lead to a greater reliance on vertical cultural transmission. On the other hand, when newly arisen variants are adaptive and favored in biased cultural transmission, interdemic processes may lead to a decrease in vertical transmission. This is because biased nonvertical transmission may effectively propagate the adaptive variants, further increasing the average growth rate of the population. These results are verified under several distinct sets of assumptions. It is also inferred that the degree and intensity of transmission bias may be the important determinants of cultural processes.

Cultural Evolution↗
PubMed2005

[Social institutions and tempering of affects as "contraints" of social change. Norbert Elias' theory on the civilization theory in light of the biologic system theory of evolution].

This study is to be regarded as a contribution to interdisciplinary research and represents an attempt to clarify the question of whether and to what extent concepts that have been developed in the field of theoretical biology and which have a high degree of importance here can also be applied to sociological phenomena. In particular it is intended to examine the question of whether the civilizing process can be adequately treated using the evolutionary concept of "Constraints". This term, which has only recently been introduced into the discussion by PERE ALBERCH as an evolutionary factor, comprises all of the internal factors which influence the further course of the evolution of a system by ruling out certain possibilities, thus showing a limiting effect. Although "Constraints" go beyond the scope of Darwinian teachings about selection by the environment, they are increasingly accepted today as evolution factors by well-known exponents of Darwinian theory (cf. MAYNARD-SMITH 1985). The increase in popularity of "constraints" is also an expression of the rediscovery of a phenomenon which was originally expressed by RUPERT RIEDL and was introduced by him into German literature in the seventies. In the clarification of this question, special reference is made to the "theory of the civilizing process" by NORBERT ELIAS, since here a highly respected scholar has presented an important sociological theory. Moreover, there is such good scientific access to ELIAS because this author exemplifies his theses in historical terms and thus to a certain extent makes his explanations verifiable in scientific terms. In the treatment of this topic, the central terms and theses of ELIAS will be presented from the considerable scope of his work, and then illustrated with the help of several selected historical case studies. Furthermore, reference will be made at the relevant points to parallels and analogies which the works of ELIAS have to other, predominantly system-theoretical concepts of evolution and which cause it to appear compatible to the latter.

Civilization↗
PubMed1978

Hydrogen (h(2)) evolution by rhizobia after synergetic culture with soybean cell suspensions.

Rhizobium japonicum cells were grown in liquid suspension cultures and separated from soybean plant cells by two to three bacterial membrane filters. Under these conditions, the plant cells elaborated materials into the medium which aided in the expression of a major rhizobial phenotype, namely, nitrogenase activity (acetylene reduction). The evolution of H(2) was also measured and this activity relative to acetylene reduction, was influenced by: (a) O(2); (b) the quantity of conditioned plant medium; and (c) ammonia. It is concluded that plant substances are of major importance in the H(2) evolution and nitrogenase activities of free-living rhizobia in suspension cultures.

Journal Article↗
PubMed2002

Learning and the evolution of language: the role of cultural variation and learning costs in the Baldwin effect.

The Baldwin effect has been explicitly used by Pinker and Bloom as an explanation of the origins of language and the evolution of a language acquisition device. This article presents new simulations of an artificial life model for the evolution of compositional languages. It specifically addresses the role of cultural variation and of learning costs in the Baldwin effect for the evolution of language. Results show that when a high cost is associated with language learning, agents gradually assimilate in their genome some explicit features (e.g., lexical properties) of the specific language they are exposed to. When the structure of the language is allowed to vary through cultural transmission, Baldwinian processes cause, instead, the assimilation of a predisposition to learn, rather than any structural properties associated with a specific language. The analysis of the mechanisms underlying such a predisposition in terms of categorical perception supports Deacon's hypothesis regarding the Baldwinian inheritance of general underlying cognitive capabilities that serve language acquisition. This is in opposition to the thesis that argues for assimilation of structural properties needed for the specification of a full-blown language acquisition device.

Algorithms↗
PubMed1993

Clonal evolutions during long-term cultures of bone marrow from de novo acute myeloid leukaemia with trilineage myelodysplasia and with myelodysplastic remission marrow.

We previously established a long-term bone marrow culture (LTBMC) system in which novel abnormal karyotypes could emerge in vitro prior to the appearance of the same karyotypes in vivo in patients with myelodysplastic syndrome (MDS). We extended our study to examine whether acute myeloid leukaemia (AML) transformed from MDS (MDS/AML) and de novo AML with trilineage myelodysplasia (AML/TMDS) show clonal evolution in LTBMC similar to that of typical AML or MDS. We also analysed the cytogenetic changes in cultures with bone marrows from AML with myelodysplastic remission marrow (AML/MRM) as well as chronic myeloid leukaemia (CML) to compare them with typical AML with respect to the liability of clonal evolution. Among the 34 AML cases, abnormal karyotypes were newly detected in four of seven MDS/AML, three of six AML/TMDS and three of three AML/MRM. Novel abnormal karyotypes were also observed in nine out of 13 CML cases after culture. In contrast, no other abnormal karyotypes were found after culture in 18 typical AML without myelodysplasia. These findings suggest that AML/TMDS and AML/MRM are different from typical AML and are similar to MDS/AML and CML in view of their potential for disease progression from latent multiple clones. Typical AML may develop from a single abnormal clone without any subclones.

Anemia, Aplastic↗
PubMed1989

A quantitative and dynamic study of endothelial cells and megakaryocytes in human long-term bone marrow cultures.

The quantitative evolution of endothelial cells (ECs) in Dexter-type human long-term bone marrow cultures (HLTBMCs) was investigated. Using monoclonal antibodies directed against von Willebrand factor (vWF) and against membrane antigens (EN-4 and PAL-E), a low percentage--usually less than 1% of stromal cells--of ECs was detected in all confluent cultures established from 11 different bone marrow samples. Generally these cells are not associated directly with the areas of myelopoiesis ("cobblestone areas"). ECs cannot be demonstrated in the adherent layer of most young, non-confluent, and of some old, HLTBMCs. In some instances, morphological features suggestive of dynamic behavior were seen (sprouting, canal formation). In addition, a very low proportion of vWF-positive megakaryocytic cells was found in 4 of 11 cultures, always in direct contact with the stromal fibroblastic cells.

Bone Marrow↗