7,355 research outputs found
Journal, J.S. Watson, Descriptions of Wild Life Expeditions and Hunting in U.S., 1878
No full textA journal kept by hunter, birder, and amateur naturalist J. S. Watson of Rochester, New York, concerning trips to Florida and Colorado, 1848-1880. The author lists Florida sea and game birds he observed and shot, discusses hunting alligators and fishing, and describes hunting bear and elk in Colorado. 46 pages of the journal are devoted to Watson\u27s trip to Florida\u27s Homosassa River and Cedar Keys with his cousin Charles A. Watson, during which Charles was killed in a boating accident. Watson details the hours he and his companion spent clinging to their capsized boat until Charles, too weak to hold on, slipped off and perished. Watson also describes the difficulties of locating and retrieving Charles\u27s body and his problems with local inhabitants.https://digitalcommons.usf.edu/envir_publications/1001/thumbnail.jp
Correspondence from Odest J. Watson to John Lewis, March 16, 1971
No full textCorrespondence from Odest J. Watson to John Lewis requesting funds to supplement a voter registration endorsed by the Sociolofy Department of Bethune-Cookman College
Evolution of Individual Group Size Preference can Increase Group-level Selection and Cooperation
No full textThe question of how cooperative groups can evolve and be maintained is fundamental to understanding the evolution of social behaviour in general, and the major transitions in particular. Here, we show how selection on an individual trait for group size preference can increase variance in fitness at the group-level, thereby leading to an increase in cooperation through stronger group selection. We are thus able to show conditions under which a population can evolve from an initial state with low cooperation and only weak group selection, to one where group selection is a highly effective force
Moderate contact between sub-populations promotes evolved assortativity enabling group selection
No full textGroup selection is easily observed when spatial group structure is imposed on a population. In fact, spatial structure is just a means of providing assortative interactions such that the benefits of cooperating are delivered to other cooperators more than to selfish individuals. In principle, assortative interactions could be supported by individually adapted traits without physical grouping. But this possibility seems to be ruled-out because any ‘marker’ that cooperators used for this purpose could be adopted by selfish individuals also. However, here we show that stable assortative marking can evolve when sub-populations at different evolutionarily stable strategies (ESSs) are brought into contact. Interestingly, if they are brought into contact too quickly, individual selection causes loss of behavioural diversity before assortative markers have a chance to evolve. But if they are brought into contact slowly, moderate initial mixing between sub-populations produces a pressure to evolve traits that facilitate assortative interactions. Once assortative interactions have become stablished, group competition between the two ESSs is facilitated without any spatial group structure. This process thus illustrates conditions where individual selection canalises groups that are initially spatially defined into stable groups that compete without the need for continued spatial separation
Entrevista con J. Watson
No full textThis interview begins by speaking of the differences between J. Watson�s experiments on
contigency perception in little children and those of the behavioural tradition. The author remains
firm about his initial conceptions on the recognition of a stimulus configuration as �social object� in
the child between 3-4 months of age: he explains that the child has some schema or strategy to
discover members of his own kind and a responses package aplicable to these members that is looking
for stimulus highly contingent with their own behaviour. The article speaks also about the partial
modifications that his model has suffered since its birth, closing with some reflections on the subject
of the production of propioceptive, visual, tactile and auditive stimulus contingent with their own
behaviour.Esta entrevista comienza planteando las diferencias entre los experimentos de J. Watson
sobre percepción de contingencias en niños pequeños y los de la tradición conductista. El autor
afirma seguir manteniendo sus concepciones iniciales acerca del reconocimiento de una
configuración estimular como �objeto social� en niños de tres-cuatro meses: explica que el niño
posee algún esquema o estrategia para descubrir miembros de la propia especie y un paquete de
respuestas aplicable a estos miembros que busca estimulaciones que sean altamente contingentes con
la propia conducta. También aborda las modificaciones parciales que ha sufrido su modelo desde
entonces, finalizando con algunas reflexiones en torno a la producción de estimulaciones
propioceptivas, visuales, táctiles y auditivas contingentes con la propia conduct
How to Measure Group Selection in Real-world Populations
No full textMultilevel selection and the evolution of cooperation are fundamental to the formation of higher-level organisation and the evolution of biocomplexity, but such notions are controversial and poorly understood in natural populations. The theoretic principles of group selection are well developed in idealised models where a population is neatly divided into multiple semi-isolated sub-populations. But since such models can be explained by individual selection given the localised frequency-dependent effects involved, some argue that the group selection concepts offered are, even in the idealised case, redundant and that in natural conditions where groups are not well-defined that a group selection framework is entirely inapplicable. This does not necessarily mean, however, that a natural population is not subject to some interesting localised frequency-dependent effects – but how could we formally quantify this under realistic conditions? Here we focus on the presence of a Simpson’s Paradox where, although the local proportion of cooperators decreases at all locations, the global proportion of cooperators increases. We illustrate this principle in a simple individual-based model of bacterial biofilm growth and discuss various complicating factors in moving from theory to practice of measuring group selection
A Simple Modularity Measure for Search Spaces based on Information Theory
No full textWithin the context of Artificial Life the question about the role of modularity has turned out to be crucial, especially with regard to the problem of evolvability. In order to be able to observe the development of modular structure, appropriate modularity measures are important. We introduce a continuous measure based on information theory which can characterize the coupling among subsystems in a search problem. In order to illustrate the concepts developed, they are applied to a very simple and intuitive set of combinatorial problems similar to scenarios used in the seminal work by Simon (1969). It is shown that this measure is closely related to the classification of search problems in terms of Separability, Non-Decomposability and Modular Interdependency as introduced in (Watson and Pollack, 2005)
The Group Selection Debate and ALife: Weak Altruism, Strong Altruism, and Inclusive Fitness (abstract)
No full textModels of the evolution of social behaviour are often framed in terms of either multi-level selection or inclusive individual fitness theory. Although both of these descriptions correctly predict changes in gene frequency (where group fitness is defined as the average individual fitness of the group members), it is still a hotly contested issue as to which provides a faithful description of the underlying causal processes at work. Furthermore, the type of model analysis used reflects the philosophical bias of the author. It is important for Alife researchers to be aware of this issue when evaluating or presenting models of social evolution, for many authors simply claim as a matter of fact that their model works via multi-level or (inclusive) individual selection, without acknowledging the alternative perspective. In this talk, two particular areas of ongoing contention between multi-level and individual selectionists will be illustrated, using examples from the Alife literature. The first of these concerns the evolution of weakly altruistic traits. These are behaviours that provide a whole-group benefit at some cost to the actor. Crucially, however, the cost to the actor is more than offset by its share of the group benefit, such that the lifetime number of offspring of the actor is increased. In a recent paper West et al. (2007, J. Evol. Biol., 20, p.415) have advocated that the evolution of such traits can be adequately explained in terms of direct fitness benefit, thus avoiding the need to invoke selection at the group level. However, this explanation hides the fact that weak altruists suffer a relative fitness disadvantage within every group. Indeed, the local attractor within any one group is the extinction of weak altruists. Therefore, the behaviour cannot spread unless groups compete and groups with more weak altruists are fitter than those with less. While the individualist methodology correctly predicts if the behaviour will evolve, it obscures the mechanistic explanation. This suggests that models couching the evolution of social behaviour in terms of individual benefit should be analysed to determine whether group structure is playing any causal role in the evolutionary dynamics. The second issue to be addressed by this talk concerns the evolution of strong altruism, i.e., behaviours where there is a reduction in the lifetime number of offspring of the actor. For such behaviours to evolve there must be a correlation in interactions, such that the recipients of an altruist’s help tend to be altruists themselves. This correlation frequently occurs in nature through the limited dispersal of kin, and is usually modelled by inclusive fitness equations that contain no notion of group fitness. However, the underlying mechanism is that kin groups with more altruists outcompete those with less. Once this is realised, it becomes apparent that other assortative group formation mechanisms can in principle produce the same effect. Appealing to kinship is therefore simply invoking one kind of assortative grouping. This talk will further elaborate on these points, including definitions of a group, and consider claims about the strength of group selection
Game theoretic treatments for the differentiation of functional roles in the transition to multicellularity
No full textMulticellular organisms are characterised by role specialisation, brought about by the epigenetic differentiation of their constituent parts. Conventional game theoretic studies of cooperation do not account for this division of labour, nor do they allow for the possibility of the plastic expression of phenotype. We address these issues by extending the notion of cooperative dilemmas to account for such interaction in which heterogeneous roles are advantageous and present an extended dynamical model of selection that allows for the possibility of conditional expression of phenotype. We use these models to investigate systematically when selection will favour an adaptive diversification of roles. We argue that such extensions to models and concepts are necessary to understand the origins of multicellularity and development
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