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Full-Text Articles in Life Sciences
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.
A Dimensionless Invariant For Relative Size At Sex Change In Animals: Explanation And Implications, Andy Gardner, David Allsop, Eric Charnov, Stuart West
A Dimensionless Invariant For Relative Size At Sex Change In Animals: Explanation And Implications, Andy Gardner, David Allsop, Eric Charnov, Stuart West
Biology Faculty & Staff Publications
Recent comparative studies across sex-changing animals have found that the relative size and age at sex change are strikingly invariant. In particular, 91%-97% of the variation in size at sex change across species can be explained by the simple rule that individuals change sex when they reach 72% of their maximum body size. However, this degree of invariance is surprising and has proved controversial. In particular, it is not clear why this result should hold, given that there is considerable biological variation across species in factors that can influence the evolutionarily stable timing of sex change. Our overall aim here …
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.
Dimensionless Invariants For The Optimal Size (Age) Of Sex Change, Eric Charnov, Unnur Skúladóttir
Dimensionless Invariants For The Optimal Size (Age) Of Sex Change, Eric Charnov, Unnur Skúladóttir
Biology Faculty & Staff Publications
Optimization models have been widely and successfully used in evolutionary ecology to predict the attributes of organisms; perhaps the greatest quantitative success is in the area of sex allocation (sex ratio, sperm versus eggs for hermaphrodites, time as a male [female] for a sex changer), where the fact of having only one mother and one father makes Darwinian fitness a simple product of gain-via-male times gain-via-female. Previous work on sex change used the maximization of this male—female product to successfully predict the direction and age (size) for sex change, and that age has been shown to imply a breeding sex …
A Trade-Off Invariant Life-History Rule For Optimal Offspring Size, Eric Charnov, Jerry Downhower
A Trade-Off Invariant Life-History Rule For Optimal Offspring Size, Eric Charnov, Jerry Downhower
Biology Faculty & Staff Publications
Optimization models have been widely and successfully used in evolutionary ecology to predict the attributes of organisms. Most such models maximize darwinian fitness (or a component of fitness) in the face of trade-offs and constraints; the numerical results usually depend on the exact form of the trade-offs/constraints. Here we report the first (to our knowledge) numerical optimum for life-history evolution which is independent of the details of the underlying trade-off, for a large array of trade-off forms. The rule is that at small litter sizes, the range in offspring size is inversely proportional to the size of the litter. Details …
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.
Facultative Sex Ratio And Population Dynamics, John Werren, Eric Charnov
Facultative Sex Ratio And Population Dynamics, John Werren, Eric Charnov
Biology Faculty & Staff Publications
No abstract provided.