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1.  Energetic constraints on an early developmental stage: a comparative view 
Biology Letters  2007;4(1):123-126.
Biologists have long sought a means by which to quantify similarities and differences in embryonic development across species. Here we present a quantitative approach for predicting the timing of developmental events based on principles of allometry and biochemical kinetics. Data from diverse oviparous species support model predictions that most variation in the time required to reach one early developmental stage—the time to first heartbeat—is explained by the body size and temperature dependence of metabolic rate. Furthermore, comparisons of this stage with later developmental stages suggest that, after correcting for size and temperature, the relationship of metabolic rate to the rate of embryogenesis is approximately invariant across taxonomic groups and stages of ontogeny.
PMCID: PMC2412922  PMID: 17999943
scaling; growth; embryology; metabolic theory; energetics
2.  Effects of metabolic rate on protein evolution 
Biology Letters  2007;3(6):655-660.
Since the modern evolutionary synthesis was first proposed early in the twentieth century, attention has focused on assessing the relative contribution of mutation versus natural selection on protein evolution. Here we test a model that yields general quantitative predictions on rates of protein evolution by combining principles of individual energetics with Kimura's neutral theory. The model successfully predicts much of the heterogeneity in rates of protein evolution for diverse eukaryotes (i.e. fishes, amphibians, reptiles, birds, mammals) from different thermal environments. Data also show that the ratio of non-synonymous to synonymous nucleotide substitution is independent of body size, and thus presumably of effective population size. These findings indicate that rates of protein evolution are largely controlled by mutation rates, which in turn are strongly influenced by individual metabolic rate.
PMCID: PMC2391229  PMID: 17911050
metabolic theory; neutral theory; mutation; scaling; molecular evolution
3.  Changes in body temperature influence the scaling of V˙O2max and aerobic scope in mammals 
Biology Letters  2006;3(1):99-102.
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 (V˙O2max) appears to scale more steeply with body size than the basal metabolic rate (BMR). Consequently, metabolic scope, defined as V˙O2max/BMR, systematically increases with body size. These observations have led some to suggest that V˙O2max 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 V˙O2max 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 V˙O2max.
PMCID: PMC2373824  PMID: 17443976
metabolic rate; allometry; metabolic theory

Results 1-3 (3)