Explores the development of the ideas of evolutionary biology, particularly as affected by the increasing understanding of genetics and of the chemical basis of inheritance.

Provides a philosophical analysis of such biological concepts as natural selection, adaptation, speciation, and evolution.

EMERGENT EVOLUTION- THE GIFFORD LECTURES DELIVERED IN THE UNIVERSITY OF ST.

A classical work on Gestalt psychology from a member of the "Berlin School." Discusses perception in relation to the environment, along with action, learning, memory, and socieity.

Hierarchical expansions of the theory of natural selection exist in two distinct bodies of thought in evolutionary biology, the group selection and the species selection traditions. Both traditions share the point of view that the principles of natural selection apply at levels of biological organization above the level of the individual organism. This leads them both to considermultilevel selection situations, where selection is occurring simultaneously at more than one level. Impeding unification of the theoretical approaches of the multilevel selection traditions (...) are the different goals of investigators in the different subdisciplines and the different types of data potentially available for analysis. We identify two alternative approaches to multilevel situations, which we termmultilevel selection [1] andmultilevel selection [2]. Of interest in the former case are the effects of group membership onindividual fitnesses, and in the latter the tendencies for the groups themselves to go extinct or to found new groups (i.e., group fitnesses). We argue that: neither represents the entire multilevel selection process; both are aspects of any multilevel selection situation; and both are legitimate approaches, suitable for answering different questions. Using this formalism, we show that: multilevel selection [2] does not require emergent group properties in order to provide an explanatory mechanism of evolutionary change; multilevel selection [1] is usually more appropriate for neontological group selection studies; and species selection is most fruitfully considered from the point of view of multilevel selection [2]. Finally we argue that the effect hypothesis of macroevolution, requiring, in selection among species, both the absence of group effects on organismic fitness (multilevel selection [1]), and the direct determination of species fitnesses by those of organisms, is untestable with paleontological data. Furthermore, the conditions for the effect hypothesis to hold are extremely restrictive and unlikely to apply to the vast majority of situations encountered in nature. (shrink)

. Introductory Remarks THEODOSIUS DOBZHANSKY The problems of reduction in biology are currently of considerable theoretical interest and practical ...

The general attributes of ecosystems are examined and a naturally occurring reference ecosystem is established, comparable with the isolated system of classical thermodynamics. Such an autonomous system with a stable, periodic input of energy is shown to assume certain structural characteristics that have an identifiable thermodynamic basis. Individual species tend to assume a state of least dissipation; this is most clearly evident in the dominant species (the species with the best integration of energy acquisition and conservation). It is concluded that (...) ecosystem structure results from the antagonistic interaction of two nearly equal forces. These forces have their origin in the Principle of Most Action (least dissipation or least entropy production) and the universal Principle of Least Action. Most action is contingent on the equipartitioning of the energy available, through uniform interaction of similar individuals. The trend to Least action is contingent on increased dissipation attained through increasing diversity and increasing complexity. These principles exhibit a basic asymmetry. Given the operation of these opposing principles over evolutionary time, it is argued that ecosystems originated in the vicinity of thermodynamic equilibrium through the resonant amplification of reversible fluctuations. On account of the basic asymmetry the system was able to evolve away from thermodynamic equilibrium provided that it remained within the vicinity of ergodynamic equilibrium (equilibrium maintained by internal work, where the opposing forces are equal and opposite).At the highest level of generalization there appear to be three principles operating: i) maximum association of free-energy and materials; ii) energy conservation (deceleration of the energy flow) through symmetric interaction and increased homogeneity; and iii) the principle of least action which induces acceleration of the energy flow through asymmetrical interaction. The opposition and asymmetry of the two forces give rise to natural selection and evolution. (shrink)

A theory in natural science is a comprehensive formula or doctrine which describes and correlates in a unified abstract form of statement the general determining factors of some special group of natural facts. It is at once inclusive, realistic and understandable. If a theoretical statement holds good, the existence and characteristics of many individual events can be inferred deductively from it. It thus gives a logical basis for empirical fact. But it is based on experience of nature, and must conform (...) to the facts of nature; these are primary, and a valid theory, no matter how broad it may be, is to be considered as itself a statement of fact, i.e., a true description of some condition which has a real and stable existence in the natural world. In its scientific usage, the term “fact” refers primarily to some datum of experience having the special character of permanence or regular recurrence; this is why scientific facts are verifiable; in this respect they differ from the passing individual events of history. Any scientific theory presupposes the stability and unequivocality of the natural facts. Hence if a theory is sound, it furnishes a reliable basis for prediction, discovery and invention. Scientific or technological creation then becomes possible; modern engineering and medicine could never have become what they are without a background of theoretical physics and biology. Obviously any natural science must always have at its disposal an ample body of observational and experimental data, but in most cases the work of collecting and verifying these is carried out under the guidance of theory. (shrink)

Diagrams refer to the phenomena overtly represented, to analogous phenomena, and to previous pictures and their graphic conventions. The diagrams of ecologists Clarke, Hutchinson, and H.T. Odum reveal their search for physical analogies, building on the success of World War II science and the promise of cybernetics. H.T. Odum's energy circuit diagrams reveal also his aspirations for a universal and natural means of reducing complexity to guide the management of diverse ecological and social systems. Graphic conventions concerning framing and translation (...) of ecological processes onto the flat printed page facilitate Odum's ability to act as if ecological relations were decomposable into systems and could be managed by analysts external to the system. (shrink)