This paper analyses the broad methodological structure of population-biological theorising. In it, I show that the distinction between initial exploratory, hypothesis-generating research and the subsequent process-reconstructing, hypothesis-testing type of research is not being made. Rather, the hypotheses generated in population biology are elaborated in such detail that students confound the initial research phase with the subsequent hypotheses-testing phase of research. In this context, I therefore analyse some testing procedures within the exploration phase and show that, as an extreme form of (...) confusion, statistical null-models are mistakenly given the status of causal population-biological theory. (shrink)

Explaining the persistence of populations is an important quest in ecology, and is a modern manifestation of the balance of nature metaphor. Increasingly, however, ecologists see populations (and ecological systems generally) as not being in equilibrium or balance. The portrayal of ecological systems as “non-equilibrium” is seen as a strong alternative to deterministic or equilibrium ecology, but this approach fails to provide much theoretical or practical guidance, and warrants formalisation at a more fundamental level. This is available in adaptation theory, (...) which allows population persistence to be explained as an epiphenomenon stemming from the maintenance, survival, movement and reproduction of individual organisms. These processes take place within a physicochemical and biotic environment that persists through structured annual cycles, but which is also spatiotemporally dynamic and subject to stochastic variation. The focus is thus shifted from the overproduction of offspring and the consequent density dependent population pressure thought to follow, to the adaptations and ecological circumstances that support those relatively few individuals that do survive. (shrink)

The balance of nature concept is an old idea that manifests itself in anumber of forms in population and community ecology. This paper focuseson population ecology, where controversy surrounding the balance ofnature takes the form of perennial debates over the significance ofdensity dependence, population regulation, and species interactions suchas competition. One of the most striking features of these debates, overthe course of the previous century in ecology, is the tendency to arguethe case on largely conceptual grounds. This paper explores twoquestions. (...) Why this tendency to settle on conceptual grounds what is soobviously an empirical issue? Are there any good conceptual arguments tobe had in this area? (shrink)

Ecology's reputation as a holistic science is partly due to widespread misconceptions of its nature as well as shortcomings in its methodology. This article argues that the pursuit of empirical laws of ecology can foster the emergence of a more unified and predictive science based on complementary modes of explanation. Numerical analyses of population dynamics have a distinguished pedigree, spatial analyses generate predictive laws of macroecology, and physical analyses are typically pursued by the ecosystem paradigm. The most characteristically ecological laws, (...) however, are found in biotic analyses in the functional trait paradigm. Holistic credentials for ecology may thus be restored on two bases: its accommodating complementary modes of analysis and explanation, and its having some laws within the least reductionistic mode consistent with its subject matter. These claims, grounded in the aspectual theory of Herman Dooyeweerd, lead to some suggestions for enhancing the versatility and usefulness of ecology—and other sciences—by balancing different research paradigms under a holistic vision. (shrink)

The effects of natural selection as a process in natural populations differs from ''survival of the fittest'' as it was formulated by Darwin in his ''Origin of Species''. The environment of a population exists of continuous changing conditions, which are heterogeneous in space. During its life each individual successively meets with differing conditions. During these confrontations the individual may appear to be ''unfit'' or ''unlucky'' and may die. If it survives it will meet the following conditions to which it is (...) ''tested'' anew, a.s.o. Hence, many individuals being less fit under certain conditions will survive and reproduce, because they did not meet a deadly moment. Therefore, being ''fit'' only refers to special prevalent conditions. In each generation the individuals thus being ''unfit'' will be eliminated together with the ''unlucky'' ones. All other individuals will survive and reproduce, notwithstanding their properties.Hence, natural selection results in the ''non-survival of the non-fit'' rather than in ''survival of the fittest'', because being ''fit'' simply means ''having survived and reproduced'', whereas being ''unfit'' can be connected with many kinds of properties and environmental conditions, e.g. being killed by a predator. Only after many generations (hundreds or even thousands) the effect of eventually dominating properties of the survivors may result in a set of properties suggesting an overall ''survival of the fittest''. This was what Darwin wanted to explain as he was mainly interested in evolutionary processes. (shrink)

Implications of variance in the time at which sibs become mature are considered, particularly with respect to the fragmentation of a parental genome over time. It is concluded that regardless of the adaptive derivation of various intra-sibship maturation schedules, they each have important genetic consequences.

In the literature the term “natural balance” occurs frequently and is used for highly divergent collections of facts and for results arrived at by different methods. In this paper it is attempted to give a review of the many possible meanings of “balance in nature”, and to evaluate the application of the term in the scientific literature.To achieve this twofold objective it seemed useful to start by giving as objective as possible a description of the “balance situation” in natural communities, (...) in analogy with the original physical concept and according to strict scientific criteria. On the basis of this working standard, part of the ecological literature is discussed with respect to statements and presumptions concerning “balance”. The extensive literature is classified according to several groups, on the one hand on the basis of the nature of the views , on the other hand according to the importance that certain authors attach to the theory of a given author. For each of these groups, an evaluation of the content of the term “balance” is given. It was found that the reasoning is not always sound and that the nature of the data on which the concept is based varies widely, which also holds for the method of reasoning applied in the conclusions drawn. In none of the publications arguments were found supporting the existence of a natural “balance situation” as formulated in the standard description. Consequently, it seemed justified to conclude that it is not correct to apply a concept “natural balance”, defined purely scientifically, to natural situations, either because “balance” in the indicated sense is simply not present or because the situation under consideration is not a natural one . The concept “natural balance” has had only heuristic value for scientific research. In other contexts it has a different value, because there criteria other than scientific or methodological ones hold for the content of a concept. It is therefore not objectionable to use the term “natural balance” in common parlance, especially since this usage makes it possible to convey to the layman a great deal in few words. (shrink)