Universal Scaling Laws in Biology: Origins, Applications, and Ramifications

生命是宇宙中最复杂的物理现象，从最大的动物和植物到最小的微生物和亚细胞单位，在巨大的规模上表现出形式和功能的非凡多样性。然而，它的许多最基本和最复杂的现象以一种令人惊讶的简单方式与尺寸成比例。例如，代谢率（维持生命所需的能量）是质量的3/4次方，范围从分子和细胞内水平到最小的单细胞细菌到最大的多细胞生物体，超过27个数量级。类似地，时间尺度（如寿命和生长速率）和大小（如基因组长度和线粒体密度）与指数的比例通常是1/4的简单幂。这些比例关系的普遍性和简单性表明，基本的普遍原则涵盖了许多生物现象的一般结构，功能和组织。 这个项目的前提是，无论大小，几乎所有的生命都是由空间填充的、分形状的层次分支网络（包括真实的和虚拟的）维持的，并最终受到限制，这些网络是由自然选择的力量优化的。以前的工作已经表明，这些原则如何解释普遍的四分之一功率标度，以及它们如何导致许多不同的生物系统的定量理解。 该项目将继续探索和阐述这些普遍原则，将其应用于生物学的其他基本问题，同时将范式扩展到其他类似的科学领域，如公司结构和城市发展。生物学问题将包括衰老和死亡率，哺乳动物的最小和最大尺寸，生态系统中的大小和能量分布，量化进化，包括热力学考虑，以及理解基因组大小的缩放及其与生物体复杂性的关系。

Life is the most complex physical phenomenon in the universe, manifesting an extraordinary diversity of form and function over an enormous scale ranging from the largest animals and plants to the smallest microbes and sub-cellular units. Yet, many of its most fundamental and complex phenomena scale with size in a surprisingly simple fashion. For example, metabolic rate (the power needed to sustain life) scales as the 3/4-power of mass over 27 orders of magnitude ranging from molecular and intra-cellular levels up through the smallest unicellular bacteria to the largest multicellular organisms. Similarly, time-scales (such as lifespan and growth-rate) and sizes (such as genome length and density of mitochondria) scale with exponents that are typically simple powers of 1/4. The universality and simplicity of these scaling relationships suggest that fundamental universal principles underlay much of the generic structure, function and organization of many biological phenomena. The premise of this project is that regardless of size, almost all life is sustained, and ultimately constrained, by space-filling, fractal-like hierarchical branching networks (both real and virtual), which are optimized by the forces of natural selection. Previous work has shown how these principles explain universal quarter-power scaling and how they lead to a quantitative understanding of many diverse biological systems. This project will continue to explore and elaborate on these universal principles by applying them to other fundamental problems in biology while extending the paradigm into other areas of science where their analogs might be applicable, such as corporate structures and urban development. The biological problems will include aging and mortality, minimum and maximum sizes of mammals, size and energy distributions in ecosystems, quantifying evolution including thermodynamic considerations, and understanding the scaling of genome size and its relationship to the complexity of the organism.