BIO120H1 Lecture Notes - Lecture 19: Corm, Seed Predation, Spasm
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BIO120H1 Full Course Notes
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Document Summary
Typical life history for higher plants and animals. Still considering a single population: but now, fecundity and survivorship vary with age, variation summarized by life tables of age-specific rates. Important implications for: evolution of life histories, conservations of populations, human affairs. Time now measured in age-class intervals: arbitrary units of time chosen to give a reasonable number of age classes for the organism in question. For microbes minutes to hours: most insects weeks, most mammals and birds intervals, humans typically five year intervals, therefore about 20 age classes. Life tables: data that summarize the life events that are statistically expected for the average individual of a specified age in a population, age of death, age and timing reproduction, usually consider females only. Survivorship schedules: age classes denoted by subscript x. Lx = probability of being alive at age x. Survivorship curve = a graph of lx vs. lx. Lx necessarily declines with x always negative.
