BISC 313 Lecture Notes - Lecture 5: Survivorship Curve, Exponential Growth, Life Table
1 Nov 2017
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Document Summary
Ecological maxim: no population can increase in size forever. Population change = (births + immigrants) - (deaths + emigrants) Life table data can be used to graphically represent a population"s age structure. Uses life tables to predict the future of populations. Mortality and survivorship: mortality is one of the four key factors influencing populations, mortality curves: the risk of mortality plotted against time. Survivorship curve: plot the number of individuals from a hypothetical cohort that will survive to reach different ages. Humans and other large animals that invest lots of energy into their young. : most individuals survive to old age (humans) Type ii: the chance of surviving remains constant throughout the lifetime (some birds) Type iii: high death rates for young, but chances for adults improve (typical of species that produce many offspring per reproductive episode) Population size can be determined by density-dependent and density-independent factors.
