Background: Evaporation is of significant ecological interest.Evaporation from an animal always results in a decrease in the temperature of the surface from which the evaporation occurs.Therefore,evaporation is a one-...Background: Evaporation is of significant ecological interest.Evaporation from an animal always results in a decrease in the temperature of the surface from which the evaporation occurs.Therefore,evaporation is a one-way transfer which causes heat loss from the organism.Biological evaporation always involves the loss of water which is a vital resource for nearly all biochemical processes.Evaporation is loss of heat via loss of body mass.Methods: The simultaneous determination of energy expenditure and loss of body mass in resting birds allows us to estimate evaporative heat loss.This method includes direct measurements of the energetic equivalent of the loss of body mass as the ratio between heat production,determined by the rate of oxygen consumption and the loss of body mass at various ambient temperatures.Results: The data indicate that evaporation was minimal at lower critical temperature and that the rate of evaporation increased at lower or higher temperatures.Obtained results indicate that passerine and non-passerine species have the ability to change their non-evaporative heat conductance the same number of times(approximately fourfold),and that their abilities in this respect are similar.Conclusions: The novelty of the study resides in the stoichiometric approach to determination of total evaporative water loss.The analysis shows that determinations by stoichiometric approach of total evaporative water loss yielded the values,which fit into the confidence intervals of all equations from literatures.The basal metabolic rate and nonevaporative thermal conductance are fundamental parameters of energetics and determine the level of physiological organization of an endothermic animal.展开更多
The metabolic scaling in the animal has been discussed for over 90 years,but no consensus has been reached.Our analysis of 2126 species of vertebrates reveals a significant allometric exponent heterogeneity.We show tha...The metabolic scaling in the animal has been discussed for over 90 years,but no consensus has been reached.Our analysis of 2126 species of vertebrates reveals a significant allometric exponent heterogeneity.We show that classes of terrestrial vertebrates exhibit the evolution of metabolic scaling.Both the allometric coefficient“a”and the allometric exponent“b”change naturally,but differently depending on the geological time of group forma-tion.The allometric coefficient“a”shows the measure of the evolutionary development of systems that forms resting metabolism in animals.Endothermic classes,such as birds and mammals,have a metabolic rate that is in an order of magnitude higher than that in ectothermic classes,including amphibians and reptiles.In the terrestrial vertebrate phylogeny,wefind that the metabolic scaling is characterized by 3 main allometric exponent values:b=3/4(mammals),b>3/4(ectotherms,such as amphibians and reptiles),and b<3/4(birds).The hetero-geneity of the allometric exponent is a natural phenomenon associated with the general evolution of vertebrates.The scaling factor decreases depending on both the external design and the size(birds vs mammals)of the an-imal.The metabolic rate and uniformity of species within a class increase as the geological start date of for-mation of the class approaches the present time.The higher the mass-specific standard metabolic rate in the class,the slower metabolic rate grows with increasing body size in this class.Our results lay the groundwork for further exploration of the evolutionary and ecological aspects of the development of metabolic scaling in animals.展开更多
基金the Russian Foundation for Basic Research for longterm support of my research (grants # 12-04-01288 and 16-04-00643)
文摘Background: Evaporation is of significant ecological interest.Evaporation from an animal always results in a decrease in the temperature of the surface from which the evaporation occurs.Therefore,evaporation is a one-way transfer which causes heat loss from the organism.Biological evaporation always involves the loss of water which is a vital resource for nearly all biochemical processes.Evaporation is loss of heat via loss of body mass.Methods: The simultaneous determination of energy expenditure and loss of body mass in resting birds allows us to estimate evaporative heat loss.This method includes direct measurements of the energetic equivalent of the loss of body mass as the ratio between heat production,determined by the rate of oxygen consumption and the loss of body mass at various ambient temperatures.Results: The data indicate that evaporation was minimal at lower critical temperature and that the rate of evaporation increased at lower or higher temperatures.Obtained results indicate that passerine and non-passerine species have the ability to change their non-evaporative heat conductance the same number of times(approximately fourfold),and that their abilities in this respect are similar.Conclusions: The novelty of the study resides in the stoichiometric approach to determination of total evaporative water loss.The analysis shows that determinations by stoichiometric approach of total evaporative water loss yielded the values,which fit into the confidence intervals of all equations from literatures.The basal metabolic rate and nonevaporative thermal conductance are fundamental parameters of energetics and determine the level of physiological organization of an endothermic animal.
文摘The metabolic scaling in the animal has been discussed for over 90 years,but no consensus has been reached.Our analysis of 2126 species of vertebrates reveals a significant allometric exponent heterogeneity.We show that classes of terrestrial vertebrates exhibit the evolution of metabolic scaling.Both the allometric coefficient“a”and the allometric exponent“b”change naturally,but differently depending on the geological time of group forma-tion.The allometric coefficient“a”shows the measure of the evolutionary development of systems that forms resting metabolism in animals.Endothermic classes,such as birds and mammals,have a metabolic rate that is in an order of magnitude higher than that in ectothermic classes,including amphibians and reptiles.In the terrestrial vertebrate phylogeny,wefind that the metabolic scaling is characterized by 3 main allometric exponent values:b=3/4(mammals),b>3/4(ectotherms,such as amphibians and reptiles),and b<3/4(birds).The hetero-geneity of the allometric exponent is a natural phenomenon associated with the general evolution of vertebrates.The scaling factor decreases depending on both the external design and the size(birds vs mammals)of the an-imal.The metabolic rate and uniformity of species within a class increase as the geological start date of for-mation of the class approaches the present time.The higher the mass-specific standard metabolic rate in the class,the slower metabolic rate grows with increasing body size in this class.Our results lay the groundwork for further exploration of the evolutionary and ecological aspects of the development of metabolic scaling in animals.
