Demographic Studies, Population Ecology


Definition of a Population
Population Parameters
Assumptions (all individuals average, identical), age class zero
Horizontal versus vertical life tables (cohorts, segments)
Actuaries: average number of deaths at every age in population
(frequency distribution of age at death)
Age-specific death rates, q(x) = force of mortality
Survivorship, l(x), fraction surviving to age x
(probability that a newborn will survive to age x
Three types of survivorship curves (Types I, II, and III)

Age-specific fecundity, m(x)
alpha = age of first reproduction, omega = age of last reproduction
Realized fecundity at age x, l(x) times m(x) = l(x)m(x)
Net reproductive rate, R(0), replacement rate of population
Expectation of further life at age x, E(x)
Reproductive value at age x, v(x)
Residual reproductive value at age x, v*(x)
Generation Time, T
Stable age distribution

Type III survivorship. Heavy juvenile mortality


Xantusia vigilis, Uta stansburiana, Eumeces fasciatus, Sceloporus olivaceus, Sceloporus undulatus, Sceloporus jarrovi, Crotaphytus wislizeni


Coluber, Masticophis, Pituophis


Chrysemys picta

Type III survivorship. Heavy juvenile mortality

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Last updated 4 March 1997 by Eric Pianka