TY - JOUR
T1 - Do Performance–Safety Tradeoffs Cause Hypometric Metabolic Scaling in Animals?
AU - Harrison, Jon
N1 - Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017/9
Y1 - 2017/9
N2 - Hypometric scaling of aerobic metabolism in animals has been widely attributed to constraints on oxygen (O2) supply in larger animals, but recent findings demonstrate that O2 supply balances with need regardless of size. Larger animals also do not exhibit evidence of compensation for O2 supply limitation. Because declining metabolic rates (MRs) are tightly linked to fitness, this provides significant evidence against the hypothesis that constraints on supply drive hypometric scaling. As an alternative, ATP demand might decline in larger animals because of performance–safety tradeoffs. Larger animals, which typically reproduce later, exhibit risk-reducing strategies that lower MR. Conversely, smaller animals are more strongly selected for growth and costly neurolocomotory performance, elevating metabolism. Animal size does not affect limiting O2 levels, based on physiological tests. Larger animals show no evidence of attempting to compensate for O2 supply limits. Smaller animals have more expensive neuromuscular and anabolic systems. Larger animals have characteristics that reduce risk and energy use. Declining mass-specific ATP demand might cause hypometric scaling of MR.
AB - Hypometric scaling of aerobic metabolism in animals has been widely attributed to constraints on oxygen (O2) supply in larger animals, but recent findings demonstrate that O2 supply balances with need regardless of size. Larger animals also do not exhibit evidence of compensation for O2 supply limitation. Because declining metabolic rates (MRs) are tightly linked to fitness, this provides significant evidence against the hypothesis that constraints on supply drive hypometric scaling. As an alternative, ATP demand might decline in larger animals because of performance–safety tradeoffs. Larger animals, which typically reproduce later, exhibit risk-reducing strategies that lower MR. Conversely, smaller animals are more strongly selected for growth and costly neurolocomotory performance, elevating metabolism. Animal size does not affect limiting O2 levels, based on physiological tests. Larger animals show no evidence of attempting to compensate for O2 supply limits. Smaller animals have more expensive neuromuscular and anabolic systems. Larger animals have characteristics that reduce risk and energy use. Declining mass-specific ATP demand might cause hypometric scaling of MR.
KW - allometry
KW - body size
KW - metabolic rate
KW - scaling
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U2 - 10.1016/j.tree.2017.05.008
DO - 10.1016/j.tree.2017.05.008
M3 - Review article
C2 - 28760361
AN - SCOPUS:85026319008
SN - 0169-5347
VL - 32
SP - 653
EP - 664
JO - Trends in Ecology and Evolution
JF - Trends in Ecology and Evolution
IS - 9
ER -