scholarly journals Analytical methods matter too: Establishing a framework for estimating maximum metabolic rate for fishes

2021 ◽  
Author(s):  
Tanya S. Prinzing ◽  
Yangfan Zhang ◽  
Nicholas C. Wegner ◽  
Nicholas K. Dulvy
Keyword(s):  
Metabolic Rate ◽  
Analytical Methods ◽  
Maximum Metabolic Rate

scholarly journals Changes in body temperature influence the scaling of and aerobic scope in mammals

2006 ◽  
Vol 3 (1) ◽  
pp. 100-103 ◽  
Author(s):  
James F Gillooly ◽  
Andrew P Allen
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Size Dependence ◽  
Maximal Activity ◽  
Scaling Exponent ◽  
Temperature Influence ◽  
Aerobic Scope ◽  
Metabolic Scope ◽  
Single Power ◽  
Maximum Metabolic Rate

Debate on the mechanism(s) responsible for the scaling of metabolic rate with body size in mammals has focused on why the maximum metabolic rate ( ) appears to scale more steeply with body size than the basal metabolic rate (BMR). Consequently, metabolic scope, defined as /BMR, systematically increases with body size. These observations have led some to suggest that and BMR are controlled by fundamentally different processes, and to discount the generality of models that predict a single power-law scaling exponent for the size dependence of the metabolic rate. We present a model that predicts a steeper size dependence for than BMR based on the observation that changes in muscle temperature from rest to maximal activity are greater in larger mammals. Empirical data support the model's prediction. This model thus provides a potential theoretical and mechanistic link between BMR and .

scholarly journals Do method and species lifestyle affect measures of maximum metabolic rate in fishes?

2016 ◽  
Vol 90 (3) ◽  
pp. 1037-1046 ◽  
Author(s):  
S. S. Killen ◽  
T. Norin ◽  
L. G. Halsey
Keyword(s):  
Metabolic Rate ◽  
Maximum Metabolic Rate

scholarly journals Reptile-like physiology in Early Jurassic stem-mammals

2019 ◽  
Author(s):  
Elis Newham ◽  
Pamela G. Gill ◽  
Philippa Brewer ◽  
Michael J. Benton ◽  
Vincent Fernandez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Metabolic Rate ◽  
Early Jurassic ◽  
Metabolic Rates ◽  
Fossil Species ◽  
X Ray Imaging ◽  
Femoral Blood Flow ◽  
Femoral Blood ◽  
Key Aspects ◽  
Maximum Metabolic Rate

AbstractThere is uncertainty regarding the timing and fossil species in which mammalian endothermy arose, with few studies of stem-mammals on key aspects of endothermy such as basal or maximum metabolic rates, or placing them in the context of living vertebrate metabolic ranges. Synchrotron X-ray imaging of incremental tooth cementum shows two Early Jurassic stem-mammals, Morganucodon and Kuehneotherium, had lifespans (a basal metabolic rate proxy) considerably longer than comparably sized living mammals, but similar to reptiles. Morganucodon also had femoral blood flow rates (a maximum metabolic rate proxy) intermediate between living mammals and reptiles. This shows maximum metabolic rates increased evolutionarily before basal rates, and that contrary to previous suggestions of a Triassic origin, Early Jurassic stem-mammals lacked the endothermic metabolism of living mammals.One Sentence SummarySurprisingly long lifespans and low femoral blood flow suggest reptile-like physiology in key Early Jurassic stem-mammals.

scholarly journals High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split

2021 ◽  
Vol 9 ◽  
Author(s):  
Philipp L. Knaus ◽  
Anneke H. van Heteren ◽  
Jacqueline K. Lungmus ◽  
P. Martin Sander
Keyword(s):  
Blood Flow ◽  
Metabolic Rate ◽  
Aerobic Capacity ◽  
Second Step ◽  
Metabolic Rates ◽  
Sectional Area ◽  
Cross Sectional ◽  
Femoral Length ◽  
Plesiomorphic State ◽  
Maximum Metabolic Rate

Varanids are the only non-avian sauropsids that are known to approach the warm-blooded mammals in stamina. Furthermore, a much higher maximum metabolic rate (MMR) gives endotherms (including birds) higher stamina than crocodiles, turtles, and non-varanid lepidosaurs. This has led researchers to hypothesize that mammalian endothermy evolved as a second step after the acquisition of elevated MMR in non-mammalian therapsids from a plesiomorphic state of low metabolic rates. In recent amniotes, MMR correlates with the index of blood flow into the femur (Qi), which is calculated from femoral length and the cross-sectional area of the nutrient foramen. Thus, Qi may serve as an indicator of MMR range in extinct animals. Using the Qi proxy and phylogenetic eigenvector maps, here we show that elevated MMRs evolved near the base of Synapsida. Non-mammalian synapsids, including caseids, edaphosaurids, sphenacodontids, dicynodonts, gorgonopsids, and non-mammalian cynodonts, show Qi values in the range of recent endotherms and varanids, suggesting that raised MMRs either evolved in synapsids shortly after the Synapsida-Sauropsida split in the Mississippian or that the low MMR of lepidosaurs and turtles is apomorphic, as has been postulated for crocodiles.

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