March 2004 | Van M. Savage, James F. Gillooly, James H. Brown, Geoffrey B. West, Eric L. Charnov
The article by Savage et al. (2004) explores the relationship between body size, temperature, and population growth, providing a theoretical framework that links metabolic rates to population dynamics. The authors derive equations for the metabolic rates of entire populations by summing over individual metabolic rates and combining them with Malthusian growth models. They show that the intrinsic rate of exponential population growth ($r_{max}$) and carrying capacity ($K$) depend on individual metabolic rates and resource supply rates. The theory predicts that $r_{max}$ scales with body mass to the $-1/4$ power and with temperature to the $-3/4$ power, while $K$ scales with body mass to the $-3/4$ power and with temperature to the $-1/4$ power. Empirical data from various organisms, including algae, protists, insects, zooplankton, fishes, and mammals, support these predicted scalings. The authors also argue that body mass and temperature can explain much of the variation in fecundity and mortality rates, and their predictions are supported by field data for marine fishes. The theory links individual metabolic rates and resource use to life-history attributes and population dynamics, providing a broad framework for understanding population growth across different organisms.The article by Savage et al. (2004) explores the relationship between body size, temperature, and population growth, providing a theoretical framework that links metabolic rates to population dynamics. The authors derive equations for the metabolic rates of entire populations by summing over individual metabolic rates and combining them with Malthusian growth models. They show that the intrinsic rate of exponential population growth ($r_{max}$) and carrying capacity ($K$) depend on individual metabolic rates and resource supply rates. The theory predicts that $r_{max}$ scales with body mass to the $-1/4$ power and with temperature to the $-3/4$ power, while $K$ scales with body mass to the $-3/4$ power and with temperature to the $-1/4$ power. Empirical data from various organisms, including algae, protists, insects, zooplankton, fishes, and mammals, support these predicted scalings. The authors also argue that body mass and temperature can explain much of the variation in fecundity and mortality rates, and their predictions are supported by field data for marine fishes. The theory links individual metabolic rates and resource use to life-history attributes and population dynamics, providing a broad framework for understanding population growth across different organisms.