Such traits include juvenile growth rates, age at sexual maturity, adult body size, age-specific fecundities, total reproduction, generation time, age-specific mortality, mean and maximum lifespan, and the intrinsic rate of natural increase (rm: see [ 3]).
The minimal generation time (or age from egg-laying to sexual maturity) was measured at 15°C, 21°C and 27°C for each C. elegans or C. briggsae strain used in the competition assays.
Subsequent calculations for net reproductive rate (total eggs produced in an average females lifetime; R0 = ∑ lx mx), generation time (average age at which a females lays her eggs; T = ∑ lx mxx/R0), and intrinsic rate of increase (instantaneous population growth rate; r = ln R0/T) [ 37, 38] were performed.
For the date calculations we estimated the species generation time (average age at which the females give birth to offspring; [ 44]) to be around 13 years, using the data from the long-term monitoring of marked individuals [[ 45, 46], authors' unpublished data).
Reproductive output (total eggs produced in an average female's lifetime; R0= ∑ lx mx), generation time (average age at which females produce eggs; T=∑ lx mxx/ R0), and intrinsic rate of increase (instantaneous population growth rate; r = ln R0/T) [ 74, 75] were subsequently calculated.
Corresponding values of u were calculated as u = μkg, where μ is the number of substitutions per site per year, k is the average sequence length under study in base pairs (excluding indels), and g is the generation time in years (i.e., age of first reproduction), which is five years in P. arguta as observed under cultivation [ 15].
Within the salmonids, coho salmon (Oncorhynchus kisutch) provides a simple study subject for studies on the effect of selection because it is strictly anadromous, and has shorter generation time and simpler age structure compared to most other salmonids; this species typically returns from the ocean at three years of age, while some younger-maturing males, "jacks," return at two years [ 15].
We first derive an analytic relation between entropy and the generation time, the mean age at which individuals produce offspring.
As proposed by Martin and Palumbi [ 9], high rates of nucleotide substitutions observed in mitochondrial genes could be related to some physiological variables such as generation time, life span, age at first reproduction, rate of population increase, and metabolic rate.
Generation time, the mean age of mothers at the birth of their offspring, is given by \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$T = \int_\alpha ^\beta {xp(x dx} $$\end{documentt}.
Given a generation time of 6.5 years (based age of first breeding of 2.5 years and annual survival of breeding adults 80% [ 34] this equates roughly to 200,000 generations, where incomplete lineage sorting of autosomal genes should be reduced unless effective population size is very large [ 35].
