By John Torday, Biology (Basel). 2015 Sep; 4(3): 573–590. The abstract:
"Homeostasis is conventionally thought of merely as a synchronic (same
time) servo-mechanism that maintains the status quo for organismal
physiology. However, when seen from the perspective of developmental
physiology, homeostasis is a robust, dynamic, intergenerational,
diachronic (across-time) mechanism for the maintenance, perpetuation and
modification of physiologic structure and function. The integral
relationships generated by cell-cell signaling for the mechanisms of
embryogenesis, physiology and repair provide the needed insight to the
scale-free universality of the homeostatic principle, offering a novel
opportunity for a Systems approach to Biology. Starting with the
inception of life itself, with the advent of reproduction
during meiosis and mitosis, moving forward both ontogenetically and
phylogenetically through the evolutionary steps involved in adaptation
to an ever-changing environment, Biology and Evolution Theory need no
longer default to teleology."
"If in effect life is a continuum that emanates from the unicellular state, then homeostasis functions at all levels of biology as a fractal, independent of scale [4]. So the properties of allostasis are a higher-level expression of the same homeostatic principles expressed at the cellular, tissue and organ levels. The examples used by McEwen and Wingfield [31,32]—blood pressure, metabolism, pH, complex patterns of bird migration—are all derived from homeostatic regulation of the unicellular state, having evolved in support of multicellular organisms. Migratory birds were used by Ernst Mayr [80] to exemplify the difference between proximate and ultimate causation in evolutionary biology, which drove a wedge between those interested in structure-function relationships (proximate) and the process of evolution itself (ultimate), generating volumes of descriptive data, undermining any attempt to understand how and why evolution has occurred based on principles of cell biology [4]."
ReplyDelete