“Organicism” often refers to the idea that ecosystems or communities are, or are like, organisms. Often implicit in early twentieth century, it has been theorized by Clements, relying on physiological and developmental concepts. I investigate the fate of this idea in major attempts of a theoretical synthesis of ecology in the first part of the twentieth century. I first consider Bioecology (1939), by Clements and Shelford, which elaborates clementsian organicism as a general framework for plant and animal ecology. Then I investigate the major animal ecology treatise of the Chicago school ecologists C. Allee, T. Park, O. Park, K. Schmidt and A. Emerson, Principles of animal ecology (1949). I show how they shifted organicism from physiology to evolution, synthesizing inspiration from both Clements and Sewall Wright, got their inspiration in evolutionary biology, and built a systematic correspondence between cells, organisms and communities. I claim that the focus on populations allowed them to apply Darwinian insights at the level of communities. Finally I argue that this theoretical synthesis fell apart in the next decade because of the rise of density-dependent accounts of population regulation.

En introduisant les notions de paradigme et de révolutions scientifiques comme « changements de paradigme », l’historien des sciences Thomas Kuhn mit en lumière une certaine incommensurabilité des théories scientifiques à travers le temps. L’opération superficiellement simple de traduire les énoncés d’une théorie ancienne dans la science présente s’avère alors plus difficile qu’une simple extraction des éléments déjà corrects dans la théorie précédente. Après avoir expliqué les conséquences de l’incommensurabilité pour la traduction inter-théorique, cet article examinera l’idée, partagée par d’autres historiens des sciences, de faire porter l’analyse historique sur des unités métathéoriques telles que l’épistémé (Foucault) ou les themata (Holton). Je conclurai que la traductibilité des sciences passées dans notre science dépend de l’unité d’analyse considérée, l’objection kuhnienne ne valant plus lorsqu’on considère des unités de niveau très élevé, ou au contraire infrathéoriques, comme les modèles.

How, when, and why organisms age are fascinating issues that can only be fully addressed by adopting an evolutionary perspective. Consistently, the main evolutionary theories of ageing, namely the Mutation Accumulation theory, the Antagonistic Pleiotropy theory, and the Disposable Soma theory, have formulated stimulating hypotheses that structure current debates on both the proximal and ultimate causes of organismal ageing. However, all these theories leave a common area of biology relatively under-explored. The Mutation Accumulation theory and the Antagonistic Pleiotropy theory were developed under the traditional framework of population genetics, and therefore are logically centred on the ageing of individuals within a population. The Disposable Soma theory, based on principles of optimising physiology, mainly explains ageing within a species. Consequently, current leading evolutionary theories of ageing do not explicitly model the countless interspecific and ecological interactions, such as symbioses and host-microbiomes associations, increasingly recognized to shape organismal evolution across the Web of Life. Moreover, the development of network modelling supporting a deeper understanding on the molecular interactions associated with ageing within and between organisms is also bringing forward new questions regarding how and why molecular pathways associated with ageing evolved. Here, we take an evolutionary perspective to examine the effects of organismal interactions on ageing across different levels of biological organisation, and consider the impact of surrounding and nested systems on organismal ageing. We also apply this perspective to suggest open issues with potential to expand the standard evolutionary theories of ageing.

Eco-evolutionary dynamics, or eco-evolution for short, are often thought to involve rapid demography (ecology) and equally rapid heritable phenotypic changes (evolution) leading to novel, emergent system behaviours. We argue that this focus on contemporary dynamics is too narrow: Eco-evolution should be extended, first, beyond pure demography to include all environmental dimensions and, second, to include slow eco-evolution which unfolds over thousands or millions of years. This extension allows us to conceptualise biological systems as occupying a two-dimensional time space along axes that capture the speed of ecology and evolution. Using Hutchinson's analogy: Time is the 'theatre' in which ecology and evolution are two interacting 'players'. Eco-evolutionary systems are therefore dynamic: We identify modulators of ecological and evolutionary rates, like temperature or sensitivity to mutation, which can change the speed of ecology and evolution, and hence impact eco-evolution. Environmental change may synchronise the speed of ecology and evolution via these rate modulators, increasing the occurrence of eco-evolution and emergent system behaviours. This represents substantial challenges for prediction, especially in the context of global change. Our perspective attempts to integrate ecology and evolution across disciplines, from gene-regulatory networks to geomorphology and across timescales, from today to deep time.

Throughout my university career, and since I began my Ph.D., Jean Gayon was there. Unlike many contributors to this volume, to the early or mid-career researchers who do French philosophy of biology today, I did not know Jean as a dissertation supervisor or a professor, but as a dissertation examiner, as expert witness to the beginning of my career and as indisputable scientific authority. For fifteen years I have been doing philosophy of evolutionary biology with Jean Gayon. In this chapter, I do not offer an analysis of “evolutionary biology according to Gayon” but I aim to pay tribute to a philosopher who was at once a “major contemporary”, a colleague, a friend, and an inspiration.

Insofar as in etiological theory, “the function of X is Z” means that X has been selected for Z, while evolutionary biology often defines adaptation as what results from natural selection, the concepts of adaptation and function overlap. Should we then finally eliminate the selection-related notion of function, replace it with that of adaptation and use “function” only when it is a question of functions sensu the causal-role theory? I examine two limit cases for the etiological theory, in which emerges a tension between the notions of function and adaptation. First, there are cases of superiority of heterozygotes, such as sickle cell anemia. Here, from an etiological point of view, the recessive allele seems to have a function (equal to its adaptive character), whereas it is at the same time dysfunctional. The other problem is the selfish genetic elements (e.g. “selfish DNA”,), which also raise the question of levels of functionality in reference to adaptations. The selfish genetic elements make visible a presupposition of the etiological theory of function, namely a homogeneity or alignment in the levels of selection. In this sense, the acknowledgment of levels of selection motivates a rethinking of the etiological notion of function.