White Paper: An Integrated Perspective on the Causes of Hypometric Metabolic Scaling in Animals

作者：Jon F. Harrison, Andrew A. Biewener, Joanna R. Bernhardt, Joseph R. Burger, James H. Brown, Zach N Coto, Meghan Duell, Michael Lynch, Emma R. Moffett, Tommy Norin, Amanda K. Pettersen, Felisa A. Smith, Ummat Somjee, James F. A. Traniello, Terrie M. Williams · 发表于：Integrative and Comparative Biology · 年份：2022 · DOI：10.1093/icb/icac136 · 被引用次数：38 · 研究领域：Physiological and biochemical adaptations、Genetics and Physical Performance、Sports Performance and Training

Larger animals studied during ontogeny, across populations, or across species, usually have lower mass-specific metabolic rates than smaller animals (hypometric scaling). This pattern is usually observed regardless of physiological state (e.g. basal, resting, field, maximally-active). The scaling of metabolism is usually highly correlated with the scaling of many life history traits, behaviors, physiological variables, and cellular/molecular properties, making determination of the causation of this pattern challenging. For across-species comparisons of resting and locomoting animals (but less so for across populations or during ontogeny), the mechanisms at the physiological and cellular level are becoming clear. Lower mass-specific metabolic rates of larger species at rest are due to a) lower contents of expensive tissues (brains, liver, kidneys), and b) slower ion leak across membranes at least partially due to membrane composition, with lower ion pump ATPase activities. Lower mass-specific costs of larger species during locomotion are due to lower costs for lower-frequency muscle activity, with slower myosin and Ca++ ATPase activities, and likely more elastic energy storage. The evolutionary explanation(s) for hypometric scaling remain(s) highly controversial. One subset of evolutionary hypotheses relies on constraints on larger animals due to changes in geometry with size; for example, lower surface-to-volume ratios of exchange surfaces may constrain nutrient or heat excha...