Theories of populations in biological communities / F. B. Christiansen and T. M. Fenchel (original) (raw)
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Population: a central concept for ecology
To search for the best concept is no idle conceit, because the experiments that a scientist may devise and therefore the facts he may discover, as well as the explanations that he offers for them, depend on how he conceives nature.''
Population and community ecology
2012
In this chapter we discuss the best methodological tools for visually and statistically comparing predictions of the metabolic theory of ecology to data. 2 Visualizing empirical data to determine whether it is of roughly the correct general form is accomplished by log-transforming both axes for sizerelated patterns, and log-transforming the y-axis and plotting it against the inverse of temperature for temperature-based patterns. Visualizing these relationships while controlling for the infl uence of other variables can be accomplished by plotting the partial residuals of multiple regressions. 3 Fitting relationships of the same general form as the theory is generally best accomplished using ordinary least-squares-based regression on logtransformed data while accounting for phylogenetic non-independence of species using phylogenetic general linear models. When multiple factors are included this should be done using multiple regression , not by fi tting relationships to residuals. Maximum likelihood methods should be used for fi tting frequency distributions. 4 Fitted parameters can be compared to theoretical predictions using confi dence intervals or likelihoodbased comparisons. 5 Whether or not empirical data are consistent with the general functional form of the model can be assessed using goodness-of-fi t tests and comparisons to the fi t of alternative models with different functional forms. 6 Care should be taken when interpreting statistical analyses of general theories to remember that the goal of science is to develop models of reality that can both capture the general underlying patterns or processes and also incorporate the important biological details. Excessive emphasis on rejecting existing models without providing alternatives is of limited use.
American Zoologist, 1981
SYNOPSIS. The role and function of theoretical ecology are examined. The case is made that theory must be recognized as an activity closely tied to, but separate and independent in objectives and perspective, from field observation and experimentation. Too literal interpretation of models, and rigid insistence on immediate congruence between theory and observation, have led to abuses and distortion of the role of theory. Examples are given to illustrate the partnership between theory and experiment, with emphasis on the partitioning and exploitation of space. The role of theory in guiding understanding and experimentation in the rocky intertidal community of the West Coast (Paine and Levin, 1981) is discussed. Models of individual movement based on random walk assumptions are summarized, with special attention to recent work by Kareiva (1982a, b, c) designed to test the applicability of diffusion models. Such models are shown to provide an excellent foundation for the study of the foraging movements of phytophagous insects: Extensions hold great promise as descriptors of movement for much wider classes of organisms and in the presence of complications such as taxis, grouping behavior, etc. Finally, some brief discussion is given on recent efforts to develop a theory of the evolution of dispersal and dormancy in heterogeneous environments.
The Concepts of Population and Metapopulation in Evolutionary Biology and Ecology
This paper aims to illustrate one of the primary goals of the philosophy of biology⎯namely, the examination of central concepts in biological theory and practice⎯through an analysis of the concepts of population and metapopulation in evolutionary biology and ecology. I will first provide a brief background for my analysis, followed by a characterization of my proposed concepts: the causal interactionist concepts of population and metapopulation. I will then illustrate how the concepts apply to six cases that differ in their population structure; this analysis will also serve to flesh out and defend the concepts a bit more. Finally, I will respond to some possible questions that my analysis may have raised and then conclude briefly.
Species diversity and population regulation: the importance of environmental feedback dimensionality
The pivotal role of evolutionary theory in life sciences derives from its capability to provide causal explanations for phenomena that are highly improbable in the physicochemical sense. Yet, until recently, many facts in biology could not be accounted for in the light of evolution. Just as physicists for a long time ignored the presence of chaos, these phenomena were basically not perceived by biologists. Two examples illustrate this assertion. Although Darwin's publication of "The Origin of Species" sparked off the whole evolutionary revolution, oddly enough, the population genetic framework underlying the modern synthesis holds no clues to speciation events. A second illustration is the more recently appreciated issue of jump increases in biological complexity that result from the aggregation of individuals into mutualistic wholes. These and many more problems possess a common source: the interactions of individuals are bound to change the environments these individuals live in. By closing the feedback loop in the evolutionary explanation, a new mathematical theory of the evolution of complex adaptive systems arises. It is this general theoretical option that lies at the core of the emerging field of adaptive dynamics. In consequence a major promise of adaptive dynamics studies is to elucidate the long-term effects of the interactions between ecological and evolutionary processes. A commitment to interfacing the theory with empirical applications is necessary both for validation and for management problems. For example, empirical evidence indicates that to control pests and diseases or to achieve sustainable harvesting of renewable resources evolutionary deliberation is already crucial on the time scale of two decades. The Adaptive Dynamics Network has as its primary objective the development of mathematical tools for the analysis of adaptive systems inside and outside the biological realm.
Theoretical Ecology, 2007
Ecologists bemoan the dearth of theory in ecology, in particular, the lack of an overarching, general theory. These complaints largely are unjustified. The components of a general theory of ecology have existed for the past half century; ecologists simply have failed to explicitly recognize them. We present a general theory of ecology and show how it relates to ecology's numerous constituent theories and models. The general theory consists of a description of the domain of ecology and a set of fundamental principles. The domain of ecology is the spatial and temporal patterns of the distribution and abundance of organisms, including causes and consequences. Fundamental principles are broad statements about the patterns that exist and the processes that operate within a domain. The seven fundamental principles of the theory of ecology are: the heterogeneous distribution of organisms, interactions of organisms, contingency, environmental heterogeneity, finite and heterogeneous resources, the mortality of organisms, and the evolutionary cause of ecological properties. These principles are the necessary and sufficient elements for a general theory of ecology. The propositions of any constituent theory of ecology can be shown to be a consequence of these fundamental principles along with principles from other science domains. The general theory establishes relationships among constituent theories through shared fundamental principles. The next challenge is to develop and integrate unified, constituent theories and to establish the relationships among them within the framework established by the general theory.
Evolution of theoretical ecology in last decades: why did individual-based modelling emerge
Ecological Questions, 2008
Mathematical models of classical theoretical ecology are state variable models. They use density of population as a state variable. Because such models posses equilibrium states and they are stable around them, classical theoretical ecology has been dominated by considerations about stability of ecological systems. Three factors observed in ecology in last decades had great influence on the gradual decline of the classical theoretical ecology: first one is development of evolutionary ecology and the stress it laid on individuals, the second one nonequlibrium way of thinking about dynamics of ecological systems and the third one various methodological doubts about application of difference and differential equations in ecology. Individual-based modeling has emerged as the result of this discussions. However, individual-based approach to modeling the dynamics of ecological systems has natural tendency to describe particular systems and to produce their detailed models. Much should be done in the future to solve general problems formulated by classical theoretical ecology using method of individual-based approach.
Introduction: Between ecology and evolutionary biology
Journal of the History of Biology, 1986
Ecology emerged as a self-conscious discipline during the last decade of the nineteenth century, growing out of a heterogeneous mix of fi'elds. Indeed, its roots are as different as field natural history and expefimental physiology.' Given that ecology was (and remains) such a heterogeneous enterprise, it is unlikely that any single perspective will suffice to describe its history. Several very different approaches have already proved fruitful. Ronald Tobey has discussed the changing importance of applied versus nonmission-oriented research in the development of ecology. Sharon Kingsland has emphasized the relative merits of theoretical versus empirical research at various points in the history of the discipline. Robert McIntosh has taken the very heterogeneity of the discipline as his perspective on its history.2 The papers that follow approach the history of ecology from yet another standpoint, namely, the changing role of evolutionary theory in the solution of ecological problems. In On the Origin of Species Darwin frequently brought evolu-1. Robert McIntosh, 7The Background of' L coloy (Cambridge: University