Overview of Population Ecology - Animal Data
Some terms
Evaluating Logistic growth
Classical data sets
Evaluating population oscillations
Classical data sets
Life Histories
Survivorship and Fecundity examples
Some Terms:
Age-specific death rate - the number of those who die in an age
interval from x to x+dx expressed as a fraction of those still alive at
age x
Demography - science dealing with growth, reproduction and vital
statistics of populations
Fecundity - reproductive potential or capability of a population
Fertility - reproductive performance of a population
Force of mortality - age specific death rate of a population
Life expectancy - mean expectation of life at birth
Life table - schedule of deaths as a function of age in a population
Malthusian parameter - overall rate of increase of a population
obtained by solving the Lotka equation in the case of an age-structured
population
Net reproduction ratio - ratio of live female births in successive
generations
Evaluating Logistic growth
Historical notes:
John Graunt (1620-1674) was originator of demography, analyzed bills of
mortality for London, pointed out that there must be some limits to
population growth since estimated population of London was doubling
every 64 years.
Thomas Malthus (1766-1834) published An Essay on the principle of
popultion in 1798, arguing that humna population has the potential for
geometric increase while the food supply he assumed could only increase
arithmetically.
Pierre-Francois Verhulst (1804-1849) constructed first version of
logistic model, but it was mostly ignored until published again by
Rayhmond Pearl and L. J. Reed in 1920.
Experiments on logistic growth:
McKendrick and Pau (1911) obtained data on E. coli, plotted the data on
logarithmic paper
T. Carlson (1913) took data on yeast growth and did first plot of
sigmoid growth.
R. Pearl (1932) grew D. melanogaster on several different size bottles
and found popultion size reached was dependent upon the volume of space
available.
G. F. Gause (1934) published The Struggle for Existence, a classic text
with many examples of logistic growth in Paramecium
L. B. Slobodkin (1954) found that the equilibrium population size of
Daphnia depended linearly on food supply
F. Ayala (1968) used Drosophila species to analyze genetic basis for
equilibrium population sizes - and that K-selection occurs
Field data on logistic growth:
Species introductions: Pheasant on Protection Island in Washington
clearly show potential logistic form til the birds were all eaten.
Invasion of collared dove in Britain, until bird watchers lost interest
J. Connell (1961) published data on settlement of Balanus on intertidal
rock surfaces showing logistic
Population oscillations:
Lynx data set of pelts traded to Hudson Bay Company
Nicholson(1954) Blowfly
Utida (1957) oscillation in bean weevil coupled to those of a parasitic
wasp.