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Reproductive Allometry And The Size-Number Trade-Off For Lizards, Eric Charnov, Robin Warne
Reproductive Allometry And The Size-Number Trade-Off For Lizards, Eric Charnov, Robin Warne
Biology Faculty & Staff Publications
The yearly reproductive allocation shows a 0.75 allometry with adult size across lizard species.
The Offspring-Size/Clutch-Size Trade-Off In Mammals., Eric Charnov, S.K.M. Ernest
The Offspring-Size/Clutch-Size Trade-Off In Mammals., Eric Charnov, S.K.M. Ernest
Biology Faculty & Staff Publications
The Smith-Fretwell model for optimal offspring size assumes the existence of an inverse proportional relationship (i.e., trade-off) between the number of offspring and the amount of resources invested in an individual offspring; virtually all of the many models derived from theirs make the same trade-off assumption. Over the last 30 years it has become apparent that the predicted proportionality is often not observed when evaluated across species. We develop a general allometric approach to correct for size-related differences in the resources available for reproduction. Using data on mammals, we demonstrate that the predicted inverse proportional relationship between number of offspring …
Reproductive Effort Is Inversely Proportional To Average Adult Life Span., Eric Charnov
Reproductive Effort Is Inversely Proportional To Average Adult Life Span., Eric Charnov
Biology Faculty & Staff Publications
Background: Forty years ago, G.C. Williams predicted that reproductive effort should be inversely related to the average adult life span across species. Aim: Use allometric life-history theory to refine that prediction. Result: Reproductive effort should be inversely proportional to average adult life span, a −1 scaling rule.
Mammal Life-History Evolution With Size-Dependent Mortality, Eric Charnov
Mammal Life-History Evolution With Size-Dependent Mortality, Eric Charnov
Biology Faculty & Staff Publications
Size dependence of mortality over the ontogeny is added to life-history optimization schemes for mammals
Size And Temperature In The Evolution Of Fish Life Histories, Eric Charnov, James Gillooly
Size And Temperature In The Evolution Of Fish Life Histories, Eric Charnov, James Gillooly
Biology Faculty & Staff Publications
Body size and temperature are the two most important variables affecting nearly all biological rates and times, especially individual growth or production rates. By favoring an optimal maturation age and reproductive allocation, natural selection links individual growth to the mortality schedule. A recent model for evolution of life histories for species with indeterminate growth, which includes most fish, successfully predicts the numeric values of two key dimensionless numbers and the allometry of the average reproductive allocation versus maturation size across species. Here we use this new model to predict the relationships of age-at-maturity, adult mortality and reproductive effort to environmental …
The Optimal Balance Between Growth Rate And Survival In Mammals, Eric Charnov
The Optimal Balance Between Growth Rate And Survival In Mammals, Eric Charnov
Biology Faculty & Staff Publications
Evolutionary theory for life-history allometry in mammals is extended to include a trade-off between body-size growth rate and adult lifespan.
Effects Of Size And Temperature On Developmental Time, James Gillooly, Eric Charnov, Geoffrey West, Van Savage, James Brown
Effects Of Size And Temperature On Developmental Time, James Gillooly, Eric Charnov, Geoffrey West, Van Savage, James Brown
Biology Faculty & Staff Publications
Body size and temperature are the two most important variables affecting nearly all biological rates and times. The relationship of size and temperature to development is of particular interest, because during ontogeny size changes and temperature often varies. Here we derive a general model, based on first principles of allometry and biochemical kinetics, that predicts the time of ontogenetic development as a function of body mass and temperature. The model fits embryonic development times spanning a wide range of egg sizes and incubation temperatures for birds and aquatic ectotherms (fish, amphibians, aquatic insects and zooplankton). The model also describes nearly …
Effects Of Size And Temperature On Metabolic Rate, James Gillooly, James Brown, Geoffrey West, Van Savage, Eric Charnov
Effects Of Size And Temperature On Metabolic Rate, James Gillooly, James Brown, Geoffrey West, Van Savage, Eric Charnov
Biology Faculty & Staff Publications
We derive a general model, based on principles of biochemical kinetics and allometry, that characterizes the effects of temperature and body mass on metabolic rate. The model fits metabolic rates of microbes, ectotherms, endotherms (including those in hibernation), and plants in temperatures ranging from 0 to 40C. Mass - and temperature - compensated resting metabolic rates of all organisms are similar: The lowest (for unicellular organisms and plants) is separated from the highest (for endothermic vertebrates) by a factor of about 20. Temperature and body size are primary determinants of biological time and ecological roles.
Evolution Of Mammal Life Histories, Eric Charnov
Evolution Of Mammal Life Histories, Eric Charnov
Biology Faculty & Staff Publications
If we assume that adult life span and age-at-maturity are described correctly by quarter power allometries across (typical) mammal species, we are tempted to look for some fundamental explanation. The explanation must acknowledge that within-species growth is sigmoid and not a power function at all, and that natural selection probably sets the age at maturity in the face of externally imposed mortality, while also allowing some mortality adjustment due to internal factors. This paper develops hypotheses to account for the above scaling rules and it predicts the numeric values of several new dimensionless numbers that interrelate growth, mortality and investment …
Allometric Scaling Of Production And Life-History Variation In Vascular Plants, Brian Enquist, Geoffrey West, Eric Charnov, James Brown
Allometric Scaling Of Production And Life-History Variation In Vascular Plants, Brian Enquist, Geoffrey West, Eric Charnov, James Brown
Biology Faculty & Staff Publications
A prominent feature of comparative life histories is the well documented negative correlation between growth rate and life span. Patterns of resource allocation during growth and reproduction reflect life-history differences between species. This is particularly striking in tropical forests, where tree species can differ greatly in their rates of growth and ages of maturity but still attain similar canopy sizes. Here we provide a theoretical framework for relating life-history variables to rates of production, dM/ dt, where M is above-ground mass and t is time. As metabolic rate limits production as an individual grows, dM=dt ~M3=4. Incorporating interspecific variation in …
Evolution Of Life History Variation Among Female Mammals, Eric Charnov
Evolution Of Life History Variation Among Female Mammals, Eric Charnov
Biology Faculty & Staff Publications
A unified approach is developed for the evolutionary structure of mammalian life histories; it blends together three basic components (individual growth or production rate as a function of body size, natural selection on age of maturity, and stable demography) to predict both the powers and the intercepts of the scaling allometry of life history variables to adult size. The theory also predicts the signs (+, -) of the correlations between life history variables when body size is held constant. Finally, the approach allows us to eliminate body size to predict the dimensionless relationships between the life history variables themselves.