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Physics has several concepts of randomness that build on the idea that the possibilities are pre-given. By contrast, an increasing number of theoretical biologists attempt to introduce new possibilities, that is to say, changes of possibility space – an idea already discussed by Bergson and that was not genuinely pursued scientifically until recently (except, in a sense, in systematics, i.e, the method to classify living beings). <br> Then, randomness operates at the level of possibilities themselves and is the basis of the historicity of biological objects. We emphasize that this concept of randomness is not only relevant when aiming to predict the future. Instead, it shapes biological organizations and ecosystems. As an illustration, we argue that a critical issue of the Anthropocene is the disruption of the biological organizations that natural history has shaped, leading to a collapse of biological possibilities.

Endocrine disruptors alter mammary gland development, impair the ability to nourish offspring, and increase the cancer risk in animal models. Epidemiological studies reveal trends towards early mammary development, nursing problems, and breast cancer in younger women. Morphological changes in mouse postnatal mammary gland development are considered sensitive markers of endocrine disruption. While the mouse mammary gland is easily amenable to morphometric measurements from the fetal stage to full maturity, the rat mammary gland grows more conspicuously into the third dimension, hindering conventional morphometric analysis. However, since rats are more commonly used in international toxicological reproductive studies, it would be beneficial to include mammary gland whole-mount analysis in these studies. Using our quantitative software to perform computer-driven analysis of the rat mammary epithelium we examined the effects of gestational and postnatal exposure to ketoconazole, an antifungal medication that affects steroidogenesis, and to the estrogen diethylstilbestrol in the mammary glands of 6- and 22-day-old females. Both treatments produced effects at both ages; the epithelium was smaller and less complex in exposed animals compared to controls. Global analysis with the permutation test showed that morphological evaluation of the PND22 mammary gland is sensitive to endocrine disruption and possibly non-monotonic. In addition to revealing that ketoconazole altered the mammary gland structure, these results suggest that for future toxicology studies, day 22 (at weaning) is more suitable than day 6 because it showed significant measurements and trends. If the collection of mammary glands is added to existing international test methods, PND22 could be a relevant time point.

Keywords: Ketoconazole, Diethylstilbestrol, endocrine disruptors, perinatal exposure, mammary gland whole mount

Biologists increasingly report anthropogenic disruptions of both organisms and ecosystems, suggesting that these processes are a fundamental, qualitative component of the Anthropocene crisis, seemingly generating disorder. Nonetheless, the notion of disruption has not yet been theorized as such in biology. To progress on this matter, we build on a specific case. Relatively minor temperature changes disrupt plant-pollinator synchrony, tearing apart the web of life. Understanding this phenomenon requires a specific rationale since models describing them use both historical and systemic reasoning. Specifically, history justifies that the system is initially in a narrow part of the possibility space where it is viable, and the disruption randomizes this configuration. Building on this rationale, we develop a formal framework inspired by Boltzmann’s entropy. This framework defines the randomization of the system and leads to analyze its consequences systematically. Notably, maximum randomization does not lead to the complete collapse of the ecosystem. Moreover, pollinators’ robustness mostly increases viability for low randomizations, while resilience enhances viability after high randomizations. Applying this framework to empirical networks, we show historical trends depending on latitude, providing further evidence of climate change’s impact on ecosystems via phenology changes. These results lead to an initial definition of disruption in ecology. When a specific historical outcome contributes to a system’s viability, disruption is the randomization of this outcome, decreasing this viability.

This is a transcribed and translated  a podcast of the interview concerning the 1st chapter of the book Biurquer: Il n’y a pas d’alternative (Bifurcate: There Is No Alternative) on the scientific, technological and political stakes of the notion of entropy. The discussion took place between Bernard Stiegler, Maël Montévil, Marie Chollat-Namy and Victor Chaix, on the 1st of July 2020.