Biology 2483A Lecture : Effects of Density
23 Dec 2011
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Document Summary
In many species, year-to-year variation in weather leads to dramatic changes in abundance and hence in population growth rates. Although these factors account for year-to-year fluctuations in the size of a population, they do not tend to increase the size of populations when they are small ad decrease the size of populations hen they are large. In the example of density dependence shown here, population growth rates decrease as population density increases. Depending on the species and the environmental conditions in its populations, lambda may vary more or less than is shown in these 2 curves. Each point represents one population. (black in density independence, population growth rates are not a function of density) (red in density dependence, population growth rates change as population density changes). How many young produced per female food limitation. The number of young per female that survived to independence declined with population density.
