Department of Philosophy, Stellenbosch University, Stellenbosch, South Africa.
Institute of Philosophy, KU Leuven, Leuven, Belgium.
Hist Philos Life Sci. 2023 Jun 8;45(2):23. doi: 10.1007/s40656-023-00581-8.
Organismal death is foundational to the evolution of life, and many biological concepts such as natural selection and life history strategy are so fashioned only because individuals are mortal. Organisms, irrespective of their organization, are composed of basic functional units-cells-and it is our understanding of cell death that lies at the heart of most general explanatory frameworks for organismal mortality. Cell death can be exogenous, arising from transmissible diseases, predation, or other misfortunes, but there are also endogenous forms of death that are sometimes the result of adaptive evolution. These endogenous forms of death-often labeled programmed cell death, PCD-originated in the earliest cells and are maintained across the tree of life. Here, we consider two problematic issues related to PCD (and cell mortality generally). First, we trace the original discoveries of cell death from the nineteenth century and place current conceptions of PCD in their historical context. Revisions of our understanding of PCD demand a reassessment of its origin. Our second aim is thus to structure the proposed origin explanations of PCD into coherent arguments. In our analysis we argue for the evolutionary concept of PCD and the viral defense-immunity hypothesis for the origin of PCD. We suggest that this framework offers a plausible account of PCD early in the history of life, and also provides an epistemic basis for the future development of a general evolutionary account of mortality.
生物体的死亡是生命进化的基础，许多生物学概念，如自然选择和生命史策略，之所以如此形成，仅仅是因为个体是有寿命的。生物体，无论其组织如何，都是由基本的功能单位——细胞组成的，而我们对细胞死亡的理解是大多数生物体死亡率的一般解释框架的核心。细胞死亡可以是外源性的，由传染性疾病、捕食或其他不幸事件引起，但也有内源性的死亡形式，有时是适应进化的结果。这些内源性的死亡形式——通常被标记为程序性细胞死亡（PCD）——起源于最早的细胞，并在生命之树中得以维持。在这里，我们考虑了与 PCD（以及细胞死亡率）相关的两个有问题的问题。首先，我们追溯了 19 世纪细胞死亡的最初发现，并将当前对 PCD 的概念置于其历史背景下。对 PCD 理解的修订要求重新评估其起源。因此，我们的第二个目的是将 PCD 的起源解释构造成连贯的论点。在我们的分析中，我们主张 PCD 的进化概念和 PCD 起源的病毒防御-免疫假说。我们认为，这个框架为生命早期的 PCD 提供了一个合理的解释，也为未来发展死亡率的一般进化解释提供了认识论基础。
