Similar to “parasitism” and “mutualism”, the concept of commensualism defines a kind of biological association, i.e. the neutral interaction between two different species. This paper shows that “commensualism” was initially defined by the Belgian zoologist and parasitologist Pierre-Joseph van Beneden (1809–1894) as referring to biological associations between organic individuals from different species. According to van Beneden, one individual derives biological advantages from this kind of association, whereas the other one remains neutral, i.e. does not receive any biological loss or gain. (...) Tracing the further history of the concept, the paper demonstrates that, while “commensalism” was initially created and used in zoology, it was taken up in other biological disciplines shortly afterward, such as botany and the emerging field of ecology. However, the experimental demonstration of the phenomenon of commensualism remained difficult. This, in turn, contributed to the nomadic existence of this concept in the life sciences of the twentieth century. (shrink)

Similar to “parasitism” and “mutualism”, the concept of commensualism defines a kind of biological association, i.e. the neutral interaction between two different species. This paper shows that “commensualism” was initially defined by the Belgian zoologist and parasitologist Pierre-Joseph van Beneden (1809–1894) as referring to biological associations between organic individuals from different species. According to van Beneden, one individual derives biological advantages from this kind of association, whereas the other one remains neutral, i.e. does not receive any biological loss or gain. (...) Tracing the further history of the concept, the paper demonstrates that, while “commensalism” was initially created and used in zoology, it was taken up in other biological disciplines shortly afterward, such as botany and the emerging field of ecology. However, the experimental demonstration of the phenomenon of commensualism remained difficult. This, in turn, contributed to the nomadic existence of this concept in the life sciences of the twentieth century. (shrink)

Sound definitions of its basic concepts are fundamental to every scientific discipline. In some instances, like in the case of the ecosystem concept, the question arises if we can define such concepts at all. And if we can define them, how should we choose from the multiple definitions available? And what are the preconditions for a scientifically sound and useful definition? On the basis of the ecosystem concept, this paper illustrates a major, often neglected distinction in the definition of ecological (...) concepts, namely that between defining criteria and additional descriptive statements connected to those definitions. As is demonstrated by examples from the literature, mixing up these categories leads to false inferences about the properties of physical objects (e.g. a particular forest) subsumed by the concept (e.g. the ecosystem). As a further consequence, this inference becomes problematic in terms of theory development and/or the application of ecological concepts for management decisions. (shrink)